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Master's thesis: The absolute sustainable building

K
Kathrine Brejnrod

This master's thesis by Kathrine Nykjær Brejnrod examines sustainability in the building sector, proposing a framework for absolute sustainability based on environmental carrying capacity rather than current relative practices. The study analyzes two case studies—a standard Danish house and a state-of-the-art upcycle house—finding both significantly exceed environmental limits for climate change and freshwater eutrophication. Projections for achieving absolute sustainability by 2050 are included, emphasizing necessary drastic reductions in impact and resource use.

Engineering
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THE ABSOLUTE SUSTAINABLE BUILDING DEFINING SUSTAINABILITY BASED ON ENVIRONMENTAL CARRYING CAPACITY J Master’s thesis Kathrine Nykjær Brejnrod Student ID: 20062459 Architectural engineering Aarhus University, Department of Engineering
Master's thesis: The absolute sustainable building
TITLE: THE ABSOLUTE SUSTAINABLE BUILDING DEFINING SUSTAINABILITY BASED ON ENVIRONMENTAL CARRYING CAPACITY PROJECT TYPE: MASTER’S THESIS IN: ARCHITECTURAL ENGINEERING – INTEGRATED ENERGY DESIGN MADE BY: KATHRINE NYKJÆR BREJNROD STUDY NR.: 20062459 CONTACT: KATHRINE_NYKJAER@HOTMAIL.COM +45 20300601 PROJECT PERIOD: JANUARY 26. – JUNE 1. 2015 SUPERVISOR: STEFFEN PETERSEN, AARHUS UNIVERSITY CO-SUPERVISOR: MORTEN BIRKVED, TECHNICAL UNIVERSITY OF DENMARK Date and signature PREFACE: This thesis is the result of 4 months of research, modelling and analysis in fulfilment of the requirements for the MSc. Architectural Engineering – Integrated energy design at Aarhus University (AU). The thesis consists of the current report with an appendix report in direct continuation. I thank Pradip Kalbar at DTU for valuable guidance, SBI for supplying background data on the reference cases used in the study as well as Charlotte Darre for proofreading. Special thanks to Morten Birkved, at Quantitative Sustainability assessment at DTU management, for generous guidance and valuable discussions.
Master's thesis: The absolute sustainable building
ABSTRACT Today the environment is under immense pressure from anthropogenic activities, and the building sector plays an important role in reducing this pressure. The current assessments of building sustainability are based on relative measures related to current practice. The purpose of this study is to present a sustainability assessment for buildings based on the impacts relative to the environmental carrying capacity. The study identifies three methods for identifying a “fair share” of the environmental carrying capacity in 11 impact categories that should be allocated to a dwelling. A normalisation of the buildings impacts compared to this fair share thus formed the basis of the absolute sustainable assessment. The absolute sustainability assessment was carried out on two reference cases, namely a standard house representing the prevalent Danish single-family house in both size and construction type and a building representing state-of-the-art in realtion to reducing environmental impacts from materials. The assessment showed that both buildings were far from absolute sustainability. The carrying capacities were immensely transgressed on climate change and freshwater eutrophication for both buildings. Further more the impact on both water depletion and freshwater ecotoxicity were approaching the limits for both the Standard house and the Upcycle house. Three scenarios for the standard house to reach absolute sustainability in 2050 were projected. The common denominator for the three scenarios were the immense reductions needed, and for instance if the living area were reduced by 40% by 2050, the impacts from use phase energy should be reduced with 93% and the same reduction would be needed for the impacts from materials and construction to reach absolute sustainability
RESUMÉ Miljøet er i dag under stærkt pres på grund af menneskeskabte påvirkninger. I kampen for at reducere dette pres spiller bygge sektoren en vigtig rolle i forhold til at udvikle bæredygtige løsninger, der kan reducere miljøbelastningen fra det byggede miljø. Definitionen af bæredygtigt byggeri er i dag baseret på relative mål defineret ud fra nuværende praksis og ikke relateret til naturens ressourcer og kapacitet. Formålet med dette studie er at udvikle en metode, til vurdering af bygningers absolutte bæredygtighed ud fra en sammenligningen af de miljømæssige påvirkninger sammenholdt med den egentlige miljømæssige bæreevne. Studiet præsenterer tre metoder, der identificerer en ”fair del” af den miljømæssige bæreevne som kan allokeres til bygningen i 11 påvirkningskategorier. Bygningens totale påvirkning i hver kategori normaliseres i forhold til den allokerede miljømæssige bæreevne for at vurdere om bygningen er absolut bæredygtig. Derudover benyttes to casestudier som grundlag for at vurdere om dansk boligbyggeri ligger inden for den miljømæssige bæreevne og derved kan betegnes som absolut bæredygtig. Den ene case er et standard hus, der repræsenterer et gængs dansk parcelhus både i forhold til størrelse og materialevalg, Standard huset, og den anden case er et parcelhus der repræsenterer state-of-the-art i forhold til nedbringelse af miljøaftrykket fra bygningens materialer, Upcycle huset. Analysen viste at begge huse var langt fra målet om absolut bæredygtighed. Både standard huset og Upcycle husets påvirkninger overskred bæreevnen langt for både klima ændring og ferskvands eutrofiering. Derudover nærmede begge huses påvirkninger på både vandmangel og ferskvands-økotoksicitet sig bæreevnen. Studiet viser desuden, hvordan standard huset kan opnå absolut bæredygtighed i 2050 igennem en fremskrivning af påvirkningen fra energiforbrug, materialer og opførsel samt antal bebyggede kvadratmeter per person. Den nødvendige reduktion for at opnå absolut bæredygtighed i 2050 vil for eksempel betyde en reduktion på 93% på påvirkningen per kvadratmeter fra både energiforbrug samt materialer og opførsel.
TABLE OF CONTENTS 1   INTRODUCTION  ..................................................................................................................................................  1   2   LITERATURE  STUDY  .........................................................................................................................................  4   2.1   SUSTAINABILITY  AND  THE  BUILDING  SECTOR  ................................................................................................................  4   2.2   CURRENT  BUILDING  SUSTAINABILITY  ASSESSMENTS  ....................................................................................................  5   2.3   COUPLING  SUSTAINABILITY  AND  CARRYING  CAPACITY  ..............................................................................................  10   2.4   ENVIRONMENTAL  CARRYING  CAPACITY  ........................................................................................................................  12   2.5   HYPOTHESES  TEST  ............................................................................................................................................................  14   3   METHOD  ..............................................................................................................................................................  15   3.1   REFERENCE  BUILDINGS  ....................................................................................................................................................  16   3.2   LCA  METHODOLOGY  .........................................................................................................................................................  17   3.3   VALIDATION  OF  MODEL-­‐BUILD  UP  .................................................................................................................................  20   3.4   ALLOCATION  OF  CARRYING  CAPACITY  ...........................................................................................................................  21   3.5   SENSITIVITY  ANALYSIS  .....................................................................................................................................................  35   4   RESULTS  ..............................................................................................................................................................  37   4.1   CARRYING  CAPACITY  FOR  A  SINGLE-­‐FAMILY  HOUSE  ...................................................................................................  37   4.2   CURRENT  ENVIRONMENTAL  PRESSURE  FROM  DWELLINGS  .......................................................................................  38   4.3   USE  PHASE  ENERGY  ..........................................................................................................................................................  46   4.4   BUILDING  LIFETIME  ..........................................................................................................................................................  48   4.5   VALIDATION  OF  MODEL  BUILD-­‐UP  .................................................................................................................................  49   4.6   SENSITIVITY  ANALYSIS  .....................................................................................................................................................  51   5   DISCUSSION  ........................................................................................................................................................  53   5.1   ALLOCATION  OF  THE  CARRYING  CAPACITY  ..................................................................................................................  53   5.2   ENVIRONMENTAL  PRESSURE  FROM  CURRENT  CONSTRUCTION  METHODS  .............................................................  55   5.3   VALIDATION  OF  MODEL  BUILD-­‐UP  .................................................................................................................................  56   5.4   THE  ABSOLUTE  SUSTAINABLE  BUILDING  ......................................................................................................................  57   5.5   UNCERTAINTIES  AND  FUTURE  WORK  ............................................................................................................................  65   6   CONCLUSION  AND  RECOMENDATIONS  .....................................................................................................  69   7   REFERENCES  ......................................................................................................................................................  71   APPENDIX  REPORT  IN  CONTINUATION  OF  THE  MAIN  REPORT  
Master's thesis: The absolute sustainable building
INTRODUCTION       1/74 1 INTRODUCTION Today our climate and ecosystems are under an immense pressure, and as a result of this we experience increasing temperatures, waste assimilation in oceans, air pollution as well as a stark increase in biodiversity loss just to mention some of the more obvious effects. We need more than 1,5 planet earths to sustain the current way of life, implying that the pressure on earth overshoots the capacity by more than 50% (Global Footprint Network, 2010). Today there is scientific consensus on identifying anthropogenic activities as the main driver behind these changes (DiMento & Doughman, 2007), but easing the pressure on both climate and ecosystems seems a severe challenge opposed by several key factors such a globally increasing population, constantly rising consumption levels, poverty and inequality problems as well as current financial and economic structures. In the attempt to reduce the human impact on both climate and environment the building sector plays a key role. The building sector stands for 40% of the global energy use and around 1/3 of the global green house gas emissions. Further more the building sector has been identified as the sector with the largest potential for significantly reducing green house gas emissions compared to other high-emission sectors. (UNEP, 2009). In 1987 the first general definition of sustainability emerged in the Brundtland report, defined as the level of development meeting the needs of the present without compromising the ability of future generations (UN, 1987). Later on, with the Rio declaration the description evolved into a sustainability definition containing three main pillars; environmental, social and financial sustainability. In the 1990s a rising public awareness on anthropogenic climate changes and the need for change also reached the construction industry, and through out the 90s a number of environmental rating systems for buildings arose. Today the list of terms describing sustainable buildings is long and includes words such as green buildings, zero-carbon buildings and eco-design. Buildings can be certified according to a range of different building assessment schemes today, with most of them leading to a rating on a scale, ie. from bronze to gold. Todays building assessment schemes are basing their sustainability definitions on current practice and many of the environmental parameters evaluated are based on ‘per area’ impacts. The assessment schemes thus does not encounter the current environmental means, the decrease in environmental means due to increasing populations or the quantity of the resulting environmental impact from the construction industry. But can a building’s environmental load be considered sustainable, when it is not related to actual environmental means of our world, but just defines a building as somewhat better than the rest? The project will try to relate the definition of environmental sustainable buildings to a framework based on the environmental carrying capacity of the earth. In this way the project will try to illuminate the actual
  INTRODUCTION   2/74   environmental means that is available for our buildings, and in that way be able to define a more absolute framework for sustainable buildings compared to todays more relative measures. To delineate the project, the focus will be on sustainability of Danish dwellings, and the main hypotheses will be:     1# ‘The environmental impact from Danish dwellings affects the environment to an extent that lies beyond a fair share of the earth’s environmental carrying capacity.’ 2# ‘Based on the environmental carrying capacity an absolute framework for sustainable buildings can be developed.’ The environmental carrying capacity here refers to the maximum pressure that a natural system can sustain without risking irreversible changes. The environment is constantly assimilating waste, cleansing the waters, dissolving and absorbing huge quantities of emissions as well as regenerating natural resources. All of these abilities are crucial for the survival and well being of flora and fauna, including humanity. For all of these regenerative forces apply that the environment only has a limited capacity, and when the pressures exceeds the capacity waste starts accumulating, concentration of air pollutants and green house gasses rises and the amount of natural resources declines. The carrying capacity thus defines the operating space within the environmental capacity assuring that the pressures do not create changes that are irreversible. The absolute framework for sustainable buildings is based on an assessment of the buildings impact in relation to the environmental carrying capacity, in contrast to today’s sustainability definition where an assessment of building sustainability is related to impacts of the current practice. TODAY ABSOLUTE Figure 2 Illustration of the sustainable buildings according to todays relative definition and the absolute definition of sustainable buildings By focusing on defining a framework for absolute environmentally sustainable buildings the project aims at defining a quantitative goal for the current development of environmentally sustainable buildings, and Current practice Environmental capacity Figure 1 Main hypothesis of the study  
INTRODUCTION       3/74 thereby enabling a basis for better and more qualified discussions and enlightened decision making in building design and engineering. A literature study was carried out to examine if other studies had already investigated a similar hypothesis and to give the author an insight into studies related to the hypotheses. The literature study thus investigated whether the hypotheses were relevant to investigate further or if they needed to be trimmed or expanded. When the hypotheses were final, a method for investigating the hypotheses were developed and the analysis were carried out. This general method approach is illustrated in Figure 3.                 Figure 3 General method approach for investigating the hypothesis
  LITERATURE  STUDY   4/74   2 LITERATURE STUDY The following chapter is a literature study carried out to test the hypotheses relevance. If the reader wishes to skip this, a summary of the findings of the literature study can be found in section 2.5 while the project method and findings are described from chapter 3 onwards. 2.1 Sustainability and the building sector With the energy crisis in the 1970s energy savings became an important topic, and energy related building regulations became an important tool in restricting the energy loss from buildings (Weissenberger et al., 2014). Then again in the 1990s a rising public awareness on the anthropogenic climate changes and a focus on environmental policies, led the building sector to recognize the need for changes in the way buildings were designed, built and operated (Haapio & Viitaniemi, 2008). The increased focus on reducing the environmental impact of buildings was followed by the emergence of terms describing buildings with reduced environmental impact, such as; green buildings, zero energy buildings or low-carbon buildings. In line with the increased focus on environmental effects the first building environmental rating system arose in the 90s, allowing an assessment of the environmental impacts of the whole building and offering the stakeholders a certification of their building projects. This focus on reducing the environmental impact from the built environment, has thus until recent years continued to primarily focus on reducing the operational energy. This has mainly been in the form of higher insulation standards as well as increased efficiencies, but in the later years also by adding energy producing installations based on renewable energy sources. In recent years a focus on the whole life cycle perspective of the building has become more prevalent, and studies have identified the embedded energy in building materials as an important factor (Minter, 2014). A life cycle assessment (LCA) allows for an assessment of the use of resources as well as the potential environmental impacts associated with a product or service. The methodology was developed already in the late 1960s and early 1970s under the name REPA (Resource and Environmental Profile Analysis), but was at that time mainly focused at the packaging industry. In the late 90s a series of standards specifying the methodology emerged to standardize the results from the LCA, since variations in data collection, methodology and system boundaries could cause large deviations in the outcome, where the series of standards used today is the ISO 14040 and the ISO 14044. (Weissenberger et al., 2014). The diffusion of the LCA methodology has though seen gaining ground in the building sector only within recent years, even though the methodology has been known in the sector for many years, e.g. in Denmark the Building Environmental Assessment Tool (BEAT) has been available since the 1990s but has been used mainly for research purposes and not widespread in the Danish building sector as a design tool. In 2013 the
LITERATURE  STUDY       5/74 life cycle thinking was introduced in the assessment scheme LEED where an LCA is still optional but improves the overall rating (U.S. GBC, 2015). In the assessment scheme DGNB a full LCA of the building is mandatory, and the performance in the LCA impacts the overall rating (DK-GBC, 2014). The life cycle analysis of a building is complex and challenging, and the accuracy of the results is dependent on the system boundaries but also to a large extent on the available data. Databases like ökobau and Ecoinvent provides general data for the LCA, but also more product specific input are becoming available with the environmental product declarations (EPD) (Weissenberger et al., 2014). The EPD’s are prioritized as LCA data for some of the building environmental assessments (DK-GBC, 2014; U.S. GBC, 2015), but it is still only a minority of the building products on the market that today has a verified EPD (EPD Danamark, 2015). 2.2 Current building sustainability assessments A wide range of building assessment tools offers evaluation and certification of a building’s sustainability. Following is a brief description of some of the assessment tools currently prevalent on the market. LEED. Leadership in Energy & Environmental Design (LEED) was developed in the U.S in 2000 by the U.S. Green Building Council, and is today most prevalent in North America (Giama & Papadopoulos, 2012). It consists of 8 primary credit categories: • Location and transportation • Materials and resources • Water efficiency • Energy and atmosphere • Sustainable site • Indoor environmental quality • Innovation • Regional priority Within each category there is specific prerequisites as well as a number of potential extra points to gain, and based on its performance a project can obtain one out of four levels of certification ranging from certified to platinum. (U.S. GBC, 2015). During a project, the design team members can track their progress in the categories towards a LEED ranging without the need of special LEED consultants (Aysin, 2011). BREEAM. Building Research Establishment Environmental Assessment Method (BREEAM) was established in 1990 in the U.K as the first tool assessing the environmental performance of the whole building (Aysin, 2011; Haapio & Viitaniemi, 2008). Together with LEED it is today the most widespread assessment scheme (Giama & Papadopoulos, 2012), with 425.000 certified buildings worldwide (BREEAM, 2015). BREEAM consists of 9 primary credit categories: • Management • Health and wellbeing • Energy • Transport • Water • Materials • Waste • Land use • Ecology and pollution Based on a projects score in each category it can be certified on a scale from pass to outstanding.
  LITERATURE  STUDY   6/74   DGNB. Deutches Gesellschaft für Nachhaltiges Bauen (DGNB) was developed in 2009 in Germany by the German government and the German Sustainable Building Council. It consists of 6 key areas: • Environmental quality • Economical quality • Sociocultural and functional quality • Technical quality • Process quality • Site quality Based on the score in the categories a project can be certified bronze, silver or gold. It requires though a minimum score in each individual category to obtain the certification, why a high average score is not necessarily sufficient. (DGNB, 2015; Giama & Papadopoulos, 2012) Though the DGNB is becoming more widespread in countries such as Germany and Denmark, only a small fraction of todays building stock in these countries have been certified according the scheme. In Denmark 219 DGNB consultants and 19 auditors have been trained, but only 10 buildings have been certified (DK- GBC, 2015). DGNB certification is still new on the Danish market, but the same tendency is seen on the German market, where DGNB has been available since 2009. In Germany around 400 consultants and 650 auditors have been trained, but the amount of certified buildings is still only around 300 (DGNB, 2015). SBTool. The Sustainable Building Tool (SBTool) was developed in 1996 (then as GBTool) by a correlation of 14 countries. The SBTool is a generic framework that allows local organisations to develop their own rating system, and is designed to allow for designers reflection on different priorities and adapt the scheme to environmental, socio-cultural as well as economic and technological aspects of a specific region. (Aysin, 2011; Matheus & Bragança, 2011). The system scope is flexible and can be modified to include from a few dozen to more than 100 evaluation criteria (iiSBE, 2015). CASBEE. Comprehensive Assessment System for Built Environment Efficiency (CASBEE) was developed in Japan and launched in 2001 by the Japanese Sustainable Building Consortium. It assesses the ratio between the building environmental quality and performance (e.g. energy efficiency) and the building environmental loads (e.g. global warming potential). (Giama & Papadopoulos, 2012). CASBEE covers four main areas; energy efficiency, resource efficiency, local environment and indoor environment, which are then all re-categorized into respectively load and quality parameters (CASBEE, 2015). The tool is very thoroughly and in the study by Siew et al. (2013) comparing different assessment schemes CASBEE has the highest methodology score, but due to its comprehensive nature its extremely difficult to implement and lacks applicability and popularity compared to e.g. LEED and BREEAM (Aysin, 2011). The assessment tools described above are just a selection of some of the many currently available building assessment methods. Most of the assessment tools are commercial, and they tend to focus on economic and financial motivation as a driver for the developers and other stakeholders to obtain the certification (Giama & Papadopoulos, 2012), but the certification of a building could also create a positive signalling effect for the stakeholder to the surrounding society (Beradi, 2012). The economic benefits of a certification in form of lower maintenance and running cost, higher productivity, increased property value etc. though needs to make up for the higher investment cost as well as the considerable cost of the actual certification, if the motivational factor is financial (Giama & Papadopoulos, 2012).
LITERATURE  STUDY       7/74 2.2.1 Criteria and weighting As described previously most of the assessment schemes seem to focus on the same main evaluation criteria; energy efficiency, material and resources, indoor environmental quality, waste and pollution, site selection and water efficiency (Beradi, 2012), and recently aspects such as economic and social value have also been included. An important factor though is how each method chooses to weigh the different criteria according to each other (Giama & Papadopoulos, 2012) as well as how the thresholds in the various criteria are derived. The different criteria are given a certain weight before being summarized into a total score, and the weighting therefor implies the significance and importance of the different criteria. In a study by Beradi (2012) different assessment schemes were compared and evaluated, including BREEAM, LEED, CASBEE and SBTool. The study showed how energy efficiency was considered the most important criteria and therefore given most weight in all of the included schemes. Weighing is thus an important factor in all assessments schemes since it dominates the overall performance score of the building, but is at the same time one of the most theoretically controversial aspects within the sustainable buildings assessments (Sharifi & Murayama, 2013; Kajikawa et al., 2011). The reasons behind the choice of criteria as well as the weighing are often not very transparent (Beradi, 2012), and according to Kajikawa et al. (2011) some choose a consensus-based weighting in the absence of a scientifically based weighting method. For example CASBEE seems to derive its weighing from a survey of building owners, operators and designers, where BREEAM derives it from a combination of consensus-based weightings as well as a ranking by a panel of experts. (Siew et al., 2013). When dealing with the criteria weighing in the building assessment schemes the literature relating to this seems profound both in terms of comparative studies as well as identification of limitations and challenges. In relation to the establishment of the criteria thresholds, on the other hand, the extent of literature seems far less extensive. Concerning the environmental criteria they seem to keep pace with the legislative development together with current best practice (Kajikawa et al., 2011; Giama & Papadopoulos, 2012), and as defined by Kajukawa et al. (2011) the primary role of the environmental assessment is to provide a comprehensive assessment of the environmental characteristics of a building, using a common and verifiable set of criteria and targets for buildings owners and designers to achieve a higher environmental standard. The threshold is thus seen to rely on current best practice, why the values are seen to be more relative than absolute, and the thresholds seem to follow a technological development rather than relying on scientific definitions of sustainable thresholds. Even though it is difficult to define the ideal criteria for sustainability, it seems clear that the different rating systems suggest advisable actions in the development towards sustainability in the building sector (Kajikawa et al., 2011), and at the same time the assessment schemes help to increase the awareness of the need for reducing the environmental impact from buildings. To exemplify the criteria weighing as well as the criteria thresholds, the Danish version of the DGNB assessment scheme is used as a basis. The manual behind the DGNB certification of office buildings in
  LITERATURE  STUDY   8/74   Denmark has recently been released, which enables others than DGNB-auditors to see and assess the actual thresholds as well as the criteria weighing (DK-GBC, 2015). The following is thus a brief review of the most significant elements in relation to criteria weighing and threshold establishing within the environmental criteria in the DGNB Denmark. 2.2.1.1 Criteria weighing in DGNB-DK Environment is one of the five main areas in DGNB, and is granted a weight of 22,5%. The area Environment is divided into a range of criteria, see Table 1 Overview of the criteria of the main area "Environmental quality" in DGNB-DK. The criterion has a total weight of 22,5% in the overall rating. Sub criterion Description Part of total rating LCA – environmental impact Reducing the environmental impact from the building throughout its life cycle. 7,9% Environmental risks related to constructional parts Reducing the use of harmful substances such as heavy metals. 3,4% Environmental impact from the extraction of materials Protection of forests, prohibition of child labour and compliance with social and environmental standards in relation to recovery of natural stone. 1,1% LCA – primary energy Reducing the primary energy demand and increasing the share of renewable energy. 5,6% Drinking water consumption and wastewater discharge Reducing water consumption and wastewater discharge, so the burden on the natural water cycle is reduced to its minimum. 2,3% Efficient land use Reducing the use of new areas for urban purposes, to make sure the land is used efficiently and that the buildings contribute to an environmental improvement of the land area. 2,3% . There are two criteria involving LCA within the main area Environment; LCA-environmental impact and LCA-primary energy. Where the first one is concerning the environmental impact from construction material etc., and the second one the primary energy demand. The environmental impact from the building materials is seen to receive a total weight of 7,9% in the overall rating of the building, and the primary energy demand 5,6%.
LITERATURE  STUDY       9/74 Table 1 Overview of the criteria of the main area "Environmental quality" in DGNB-DK. The criterion has a total weight of 22,5% in the overall rating. (DK-GBC, 2014) Sub criterion Description Part of total rating LCA – environmental impact Reducing the environmental impact from the building throughout its life cycle. 7,9% Environmental risks related to constructional parts Reducing the use of harmful substances such as heavy metals. 3,4% Environmental impact from the extraction of materials Protection of forests, prohibition of child labour and compliance with social and environmental standards in relation to recovery of natural stone. 1,1% LCA – primary energy Reducing the primary energy demand and increasing the share of renewable energy. 5,6% Drinking water consumption and wastewater discharge Reducing water consumption and wastewater discharge, so the burden on the natural water cycle is reduced to its minimum. 2,3% Efficient land use Reducing the use of new areas for urban purposes, to make sure the land is used efficiently and that the buildings contribute to an environmental improvement of the land area. 2,3% In each criterion a number of points is awarded based on a rating of the projects performance, which is then again weighed into a compliance rate. To achieve the lowest certification grade, bronze, the project needs to have an overall compliance rate of 50% though with a minimum of 35% in all five main areas, and to achieve the highest grade, gold, the overall compliance rate should be 80% with a minimum of 65% in all areas. (DK-GBC, 2014) 2.2.1.2 Thresholds in DGNB-DK When the projects performance within each criterion is evaluated it is based on a lower limit value (the minimum threshold), a reference value (good practice) and a target value (best practice) defined by DK-GBC (2014). The definitions of respectively the minimum threshold and the target value for the criterion LCA- environmental is seen for the five evaluated impact categories from Table 2. When looking at climate change (GWP) the minimum threshold for a certification is seen to be 140% of the reference building, and the target value (best practice) is seen to be 70% of the reference.
  LITERATURE  STUDY   10/74   Table 2 Threshold values relative to impact of the DGNB reference in the criterion LCA-Environmental impact Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Photochemical Ozone Creation Potential), Acidification Potential (AP) and Eutrophication Potential (EP). (DK-GBC, 2014) GWP ODP POCP AP EP Minimum 140% 1000% 200% 170% 200% Reference 100% 100% 100% 100% 100% Target 70% 70% 70% 70% 70% When looking at the primary energy demand the same tendencies are seen, see Table 3. For the non- renewable energy the minimum value is defined as 140% of the reference and the target value is defied as 70% of the reference. At the total energy demand the target value though is seen to be defined as 40% of the reference. Table 3 Threshold values relative to the impact of the DGNB reference in the subcriterion LCA-Primary energy (DK-GBC, 2014) Non-renewable energy Total energy demand Minimum 140% 140% Reference 100% 100% Target 70% 40% In the two former sub-criteria, it is thus seen that the maximum point is given for at reduction of respectively 30% and 60% of the established reference building depending on the impact category. As described previously the thresholds for the reference building are set up according to reference values in relation to current practice, but when it concerns the more exact basis on which basis these reference values have been derived no information could be found. The minimum value is seen varying from 100% to 200% of the impact of the reference building depending on the impact category, and depending on the project’s performance in other criteria this could be enough for a DGNB certification. Since the certification is based on an overall assessment of the buildings performance, a building performing equal to or worse than the reference building in the two discussed criteria would be certifiable. 2.3 Coupling sustainability and carrying capacity As identified in the previous section the definition of environmentally sustainable buildings in the assessment schemes seem to rely on thresholds related to current practice, and the development seem to progress with the technological development without a specific target in sight. The environmental load of a
LITERATURE  STUDY       11/74 building is thus related to the load of a reference building and not to a scientific baseline when evaluating if a building is sustainable or not. In a study by Olgay & Herdt (2004) the need for an identification of criteria based on a scientific understanding of environmental capacity instead of the current practice in traditional environmental impact assessment was identified, but to the knowledge of the author, literature identifying methods for this coupling of building impact and environmental capacity is almost non-existing. Though with the exception of one scientific paper by Bendewald and Zhai (2013), where a method of evaluating if a building is sustainable based on the building’s environmental impact together with the environmental carrying capacity of the site associated to the building is presented. The method balances the building’s carbon emissions throughout the building lifetime with the sites carbon balance throughout the same period, and if the building emits more carbon than the net uptake of the site, the building is considered unsustainable. (Bendewald & Zhai, 2013). Linking building sustainability with environmental carrying capacity of the site involves several obviously ambiguities though. For instance a bigger site would automatically result in a more sustainable evaluation of a building, but also the general assumption that the entire globe could be covered by buildings leaving no area for food production etc., but with an evaluation of each building as sustainable as long as the site capacity and the building impact was balanced. Looking somewhat broader than buildings, the term Ecological Footprint was introduced by William E. Rees in 1992 as a way to compare human impact on the earth (or a specific area) with the biocapacity of the same area. The Ecological footprint measures the amount of productive land and water area required to produce all resources consumed by a population (or activity) as well as for absorbing the waste (pollution etc.) generated (Global Footprint Network, 2010). The Ecological Footprint is measured in Globale Hectares (gha), which are hectares with a yield corresponding to the global average yield. When the ecological footprint for a certain area, e.g. the whole world, is found, it is compared to the actual biocapacity of the same area to visualize a potential gab between human impact and nature’s capacity. The overshoot according to the ecological footprint method is currently 1,5 planet earths. The Ecological Footprint is a popular indicator on humanity’s level of sustainability (or unsustainability) and is adopted by institutions such as the World Wild Life Fund as well as a long list of national and local environmental organizations and research institutes. The method has though received criticism in different areas. First of all for the use of the hypothetical land measure gha, which has the possibility of being intepreted as realistic or even actual land areas, and further more for assuming that all important environmental impact from humans can be indicated by land use. The ecological footprint in this way turns land scaricity into a primary concern and neglects impacts that can not directly be related to this, (Van den Bergh & Grazi, 2013). In 2013 Birkved & Goldstein presented a method combining Urban Metabolism (UM) and LCA to assess the susainability of urban systems by including both upstream and downstream effects. This combined UM-LCA
  LITERATURE  STUDY   12/74   they further relate to the environemntal burden boundaries to enable an assessment of the absolute sustainability of the urban system. Birkved & Goldstein (2013) thus relates the environemntal impact with environemental capacity to define absolute sustainability. 2.4 Environmental carrying capacity The following sections looks into studies establishing thresholds on environmental carrying capacity to identify a basis/baseline for the further work. Humanities influence on climate change as well as changes on ecosystems are followed closely by the worlds leading scientist, and assessments from the Intergovernmental Panel of Climate Change (IPCC) as well as the Millennium Ecosystem Assessment (MEA) provides amongst others insight into these changes. For many years scientist around the world have tried to estimate and quantify both humanity’s impact on the environment and the maximum impact the earth can sustain. In 2009 Rockström et al. introduced the concept of “Planetary boundaries”, defined as; the safe operating space for humanity with respect to the earths system and in association with the planet’s biophysical subsystems and processes. These boundaries are defined for certain subsystems of the earth where the reactions are non-linear, and where a transgression of a certain threshold could take the system into a whole new state and generate unacceptable environmental change (Rockström et al., 2009), and the thresholds thus define a safe limit for the systems “tipping point”. Rockström et al. (2009) has identified nine of such systems processes for which they find a planetary boundary is needed; § Rate of biodiversity loss § Climate change § Interference with the nitrogen and phosporus circle § Stratospheric ozone depletion § Ocean acidification § Global freshwater use § Change in land use § Chemical pollution § Atmospheric aerosol loading According to Rockström et al. (2009) three of these boundaries have already been crossed; climate change, rate of biodiversity loss and interference with the nitrogen cycle, see Figure 4. For the global freshwater use, change in land use, ocean acidification and interference with the global phosphorous cycle they find that humanity might be approaching these boundaries soon.
LITERATURE  STUDY       13/74 In a recent scientific paper Bjørn & Hauschild (2015) takes the work on carrying capacity one step further, as they present a framework of carrying capacity based normalisation references for LCA. They present 1 person equivalent (PE) as an impact equivalent to the one persons annual share of the carrying capacity for eleven impact categories. This is in contrast to the traditional normalisation where impacts are compared to society’s background impacts and not to the actual capacity. Bjørn et al. (2015) has in their study defined carrying capacity as the maximum pressure a natural system can sustain without risking irreversible changes, where irreversible changes refer to changes impossible or impractical to reverse within a human timescale. From Table 4 the normalised reference per category per person year is seen, and as the table shows the study includes a normalised reference in a global perspective as well as a European. The variations in the Global and European person equivalent capacity is due to differences in population density as well as differences in the areas total capacity. Table 4 Normalised reference based on carrying capacity of respectively the World and Europe, defined per person year. (Bjørn & Hauschild, 2015) Impact category Global Europe Terrestrial acidification [mole H+ eq] 2,3⋅103 1,4⋅103 Terrestrial eutrophication [mole N eq] 2,8⋅103 1,8⋅103 Water depletion [m3 ] 306 490 Figure 4 The green circle represents the safe operating space for the nine systems, and the red wedges referesents an estimate of the current position for each variable (Rockström et al., 2009)
  LITERATURE  STUDY   14/74   Land use , soil erosion [tons eroded soil] 1,8 1,8 Land use, biodiversity [m2 *year] 1,5⋅104 9,5⋅103 Climate change Temperature increase, 2° [kg CO2 eq] 985 985 Radiative forcing, 1W*m2 [kg CO2 eq] 522 522 Ozone depletion [kg CFC-11 eq] 0,078 0,078 Freshwater eutrophication [kg P eq] 0,85 0,46 Marine eutrophication [kg N eq] 29 31 Photochemical ozone formation [kg NMVOC eq] 73 47 Freshwater ecotoxicity [PAF]*m3 *day 1,9⋅104 1,0⋅104 The definition of the carrying capacity within the impact categories is based on scientific consensus. However, for the category climate change they suggest two boundaries for the carrying capacity; one based on limiting global warming to 2° above pre-industrial levels and one based on reducing the radiative forcing to 1W*m2 as suggested by Rockström et al. (2009). As showing from Table 4 the two differs almost by a factor two, where the boundary based on the radiative forcing is seen to be the most precautionary. The study relates the carrying capacity in each category to the actual impact. In most of the categories the relation between the capacity and the impact is bigger when only Europe is considered compared to a global scale, suggesting that the environmental pressure compared to the size of the carrying capacity of Europe is higher than the average for the rest of the world. When looking at Europe the study found the impact exceeded the capacity in three categories; land use (soil erosion), climate change as well as photochemical ozone formation. (Bjørn & Hauschild, 2015) 2.5 Hypotheses test From the literature study it has been clarified how current building assessment schemes defines sustainable buildings relative to the environmental pressure from current construction methods, and therefor not in relation to actual environmental capacity. Further it showed how the coupling of building sustainability and environmental capacity is almost non-existing in the literature, but though present to a limited extent in other aspects, i.e. Urban systems. The literature study has thus neither confirmed nor ruled out the hypotheses, but the literature study has verified the need for environmental benchmarks within the carrying capacity of the earth, and the hypotheses is therefore found highly relevant for further investigation. Further more the literature study gave an insight into relevant work in relation to establishing the environmental carrying capacity, which will form an important basis for the further work into testing the hypotheses.
METHOD       15/74 3 METHOD A methodological framework is evolved to investigate the hypotheses stated in section 0, with the following three activities forming the basis: 1) Allocation of environmental carrying capacity to a dwelling 2) Estimation of current environmental pressures from a dwelling 3) Analysis investigating possible solutions for reaching absolute sustainable dwellings First an allocation of carrying capacity is carried out in order to identify the share that is available to a dwelling. The carrying capacity identified by Bjørn & Hauschild (2015) defines the capacities available per person. The allocation scenarios look into how large a share of one person’s capacity could be allocated to the construction and running of dwellings. The part allocated to dwellings thus forms the basis of comparison, when evaluating whether or not a dwelling is sustainable. Then to assess how the impact from new dwellings relate to the environmental capacity two reference cases are used; the ‘Standard house’ and the ‘Upcycle house’. The standard house is reflecting today’s prevalent building practice and the Upcycle house reflects today’s best practice when it comes to reducing environmental impact from materials. Through an LCA the environmental impacts of the buildings is identified and then further compared to the identified capacity allocated thereto. If the impact from the building stays within the boundaries of the allocated carrying capacity, the building is considered absolute sustainable. An analysis of the potential for attaining the absolute sustainable building is carried out to form a solution frame. Based on the analysis a range of scenarios is finally developed to identify the required changes if reaching the absolute sustainable building in 2050.
  METHOD   16/74   3.1 Reference buildings The two case-buildings the Standard house and the Upcycle house are described in the following. A fictive location in the town of Hedensted, Denmark is assumed for both houses when performing the LCA. 3.1.1 Standard house The Standard house is a detached single-family house with a gross area of 149m2 (net area of 128m2 ) 1 . The house is one-storey and consists of: living room, kitchen, dinning room, four bedrooms, two bathrooms and a scullery. The house is built on a line foundation of concrete, with a socket of insulated lightweight concrete blocks, and the ground slab is reinforced concrete on EPS, with wooden or tiled flooring. The outer walls consist of an inner leaf of aerated concrete, mineral wool insulation and an outer leaf of masonry. The roof consists of wooden roof trusses with a solid under-roof and roofing tiles, with mineral wool as insulation and a ceiling of surface mounted plasterboards. The inner walls are aerated concrete with plaster and painted glassfelt, and timer aluminium clad windows with triple glazed panes. Facade Floorplan Materials and build up of the house in accordance with SBI (2015), and a full inventory list can be seen from appendix B. 3.1.2 Upcycle house The Upcycle house is a detached single-family house with a gross area of 129m2 (net area of 104m2 ). The house is one-storey and consists of: a living room, a kitchen, four bedrooms, one bathroom, scullery and a pantry. The house also includes a terrace and a greenhouse as an integrated part of the house. The materials used for the house are all recycled of reused products. The house is founded on screw- foundations, and two freight containers forms the bearing structure. The façade is mounted with plates of // 1 The net area is not apparent in the background report, and is therefor assumed based on the gross area Figure 5 Illustration of the standard house layout and façade. (SBI, 2015)
METHOD       17/74 composite material and the roof with aluminium plates. The windows are triple glazed, and the internal walls and floors are covered with OSB plates. All insulation used in the house is paperwool insulation made from recycled paper waste. Facade Floorplan The Upcycle house is one of the five MiniCO2 houses in Nyborg Denmark carried out as part of a project by Realdania. Materials and the build-up of the house are according to SBI (2013), and a full inventory list can be seen from appendix A. 3.1.3 Energy consumption Both houses are built according to the Danish energy class 2015, and when nothing else is stated the energy consumption is set to 37,8 kWh/m2 /yr, and the distribution of the energy consumption is assumed to be 35% electricity and 65% heat according to SBI (2008). When simulations, with an energy consumption according to energy class 2020, are carried out the energy consumption used is 20 kWh/m2 /yr. An increased amount of insulation or additional modifications of the building design is not accounted for, and the relation between heat and electricity is assumed unaltered. For construction an energy consumption of 67,7 kWh/m2 is assumed based on a case study of a detached brick house (Cuéllar-Franca & Azapagic, 2012). The energy for construction is thus not differentiated from the Standard house to the Upcycle house. 3.2 LCA methodology LCA is initially intended for relative performance indications. The current study though is based on the more controversial use of LCA presented in the study by Bjørn & Hauschild (2015), where the results are normalised according to carrying capacity. The LCA in this study is therefore used to estimate an absolute impact from the buildings. All LCA’s are carried out using the software GaBi and based on the methodology described in the following. Figure 6 Illustration of the layout and façade of the Upcycle house (SBI, 2013)
  METHOD   18/74   3.2.1 Functional unit When nothing else is stated the functional unit is the whole building, respectively the Standard house or the Upcycle house. The reference study period is 50 years. 3.2.2 System boundaries The system boundaries are set to include as many relevant impacts as possible through the life cycle of the building, which means they deviate in some areas from prevalent used system boundaries on building LCA. The DGNB boundaries for example leave out the construction phase with reference to an increased uncertainty. LCA of buildings usually serve a comparative purpose, i.e. benchmarking of one building to another, in which situation leaving out areas of uncertainty and eliminating deviations in assumptions can be meaningful. This study though aims to estimate the absolute impact – basically meaning the total impact of the building, and leaving out areas with great uncertainties involved, thereby excludes potentially important contributions to the absolute impact. From Figure 7 the system boundaries of the LCA on both buildings are illustrated. Building life cycle stages Production Extraction √ Transport √ Production √ Constructi on Material spilled √ Energy for cons. √ Transport √ Land conversion – site √ Maintenance − Use Replacements √ Repair √ Modifications − Operational energy √ Water − Land use – site √ End of life Transport √ Demolition (√) Waste treatment √ Recycling √ Landfill √ Figure 7 System boundaries used for the LCA. √ = included, − = not included, (√) = partial included
METHOD       19/74 3.2.3 Background data 3.2.3.1 Building materials For the Life Cycle Inventory (LCI) different data on the building materials are needed, such as; Type of materials used, amounts of building materials used and physical properties of materials (density etc.). The type and amount of the materials in the two buildings are provided by the SBI in accordance with their work on respectively the Standard house (SBI, 2015) and the Upcycle house (SBI, 2013). When needed, physical properties of the materials such as densities and dimensions are estimated together with recycling rates of the materials, see appendix D. In the construction phase a material spill of 1% is assumed. Further more a spill of 5% of recycled material is assumed when accounting for effects from avoided production at the end of life stage. Materials for repair throughout the building lifetime 1% of the initial material amount is assumed, but only for materials exposed to the ambient environment, such as roof tiles, plaster boards etc. Repair of non-exposed materials is therefore assumed non-existent. For a detailed description of material types and amounts see appendix A and B. 3.2.3.2 Transport Two types of datasets with different boundaries are used, one “at plant” and one “at regional storage”. When using “at regional storage” all impact until regional storage are included also transport, which here is assumed identical to the site and therefore no additional transport is added. When using “at plant”, additional transport from plant to site is added since this is not included. The distances is assumed according to the recommendations by Ecoinvent (2007, p.13) when possible, and otherwise by estimates based on available information from product manufactures. Transport is included from site to disposal for all materials based on the distance from site to the nearest recycling depot. 3.2.3.3 LCI Dataset Ecoinvent 2.2 is used as the primary database for materials and processes used in the modelling. Preferably the datasets are country specific to Denmark, but this has only been available with datasets on electricity mix. Otherwise average European datasets or average Swiss datasets have been preferred. For a few more rarely used building materials Ecoinvent provided no useful dataset in which cases EPD-data are used instead. Due to different characterization methods the impacts from the EPD’s are not directly comparable, and the EPD’s are thus only used to provide data on product content, which is then modelled using Ecoinvent datasets. For a detailed description of datasets used see appendix A and B, and for the end of life flows see appendix C.
  METHOD   20/74   3.2.4 Impact categories The following 11 impact categories are assessed in the project: § Terrestrial acidification [mole H+ eq.] § Water depletion [m3 ] § Land use – soil erosion [ton eroded soil] § Land use – biodiversity [m2 *year] § Climate change [kg CO2 eq.] § Ozone depletion [kg R-11 eq.] § Freshwater eutrophication [kg P eq.] § Marine eutrophication [kg N eq.] § Terrestrial eutrophication [mole N eq.] § Photochemical ozone formation [kg NMVOC eq.] § Freshwater ecotoxicity [PAF]*m3 *day For a short introduction to the environmental effects associated with the impact categories see appendix F. 3.2.5 Normalization The resulting impacts of the building(s) are normalised in relation to the carrying capacity allocated to the building in each specific impact category. The normalised impact (IN) for a building (B) in the impact category (i) is thus calculated as: !!,!,! = !!,! !!!",! Where I is the total impact of the building and CC is the carrying capacity allocated to the specific building type (BT). The normalised impact for each category is thus the actual impact divided by the allocated carrying capacity. 3.3 Validation of model-build up The inventory data on the reference house and the Upcycle house are based on two reports by the Danish Building Research Institute (SBI) published in 2015 and 2013 (SBI, 2015; SBI, 2013). The output results from the GaBi models are compared to the results from these two reports to validate the overall model build- up as well as to give an insight into the magnitude of the deviations an LCA with approximately the same prerequisites has. The inventories for the absolute models are in accordance with the SBI models when comes to material amounts and types, but the system boundaries of the absolute models described in 3.2.2 differ from those set by SBI. The two absolute models are therefor altered to align the prerequisites of respectively the SBI model and the absolute model excluding lifecycle stages etc. to allow for a comparison, see Figure 8 for an illustration of the system boundaries of respectively the SBI models and the absolute models.
METHOD       21/74 Production phase Use phase End of life SBI Model Abs. Model SBI Abs. Model SBI Abs. Model Extraction X X Maintenance Demolition (X) Transport X X Repair (X) Transport X Production X X Replacement X X Waste handling X X Construction X Modifications Recycling X X Landconversion X Energy X X Landfill X X Water Land use X Figure 8 Variations in system boundaries of the SBI models and the absolute models Besides the variations in system boundaries, which to the extent possible is adjusted, there are also variations in the database background. The SBI models are based on ESCUO database and the absolute models on the Ecoinvent database. A full description of the differences between the SBI models and the absolute models as well as the alternations made to the absolute model for the validation process can be seen in appendix I. It is though important to notice that the alternations of the two absolute models to fit the SBI prerequisites are only used in the validation process, and does not form the basis for the models in the further process. 3.4 Allocation of carrying capacity The following section will describe the method(s) used to allocate a “fair share” of the environmental carrying capacity to the dwelling. There is though no unequivocal solution to this issue, why the definition of this “fair share” might vary depending on the eyes seeing, and the methods presented here just represent some of the ways this allocation could be carried out. The methods used here all take their basis in the person equivalent carrying capacity identified by Bjørn & Hauschild (2015), see section 2.4. This person equivalent carrying capacity is based on an equal distribution of the world’s capacity, implying that all people in the world have an equal share of the environmental capacity to their disposal.
  METHOD   22/74   To identify the person equivalent carrying capacity, Bjørn & Hauschild (2015) divided the total environmental carrying capacity of the world by the total number of people. When assessing one person’s impact related to the person equivalent carrying capacity both direct and indirect impacts should therefore be included. A person affects the environment in a number of different ways - daily-life products and services ranging from food and transportation to the construction and running of their dwelling. Apart from these more direct and obvious impacts, a person also impacts the environment more indirectly by public activities or consumption, and the total impact from one person thus includes both the direct impacts and a share of the world’s public impacts that is not directly linked to individual household consumption. When allocating a share of the world’s carrying capacity, the total capacity is first allocated equally to the entire population, then from one person’s capacity a share can be allocated to household, then again from the household a share can be allocated to housing and then finally only a share of the housing category is actually related to the dwelling. This general approach is the allocation methods used in this study illustrated by Figure 9. Figure 9 General allocation method used to allocate a share of the World’s capacity to the dwelling When the share of one person’s carrying capacity allocated to the dwelling is identified, the carrying capacity for an entire dwelling is found by multiplying this share by the average number of residents in a dwelling. The annual carrying capacity for a dwelling (CCdwe) for a specific impact category (i) is thus calculated as: CCdwe,i = CCPE,i * AHH,i * AHDW,i * Rave Where CCPE is the total person equivalent carrying capacity according to Bjørn et al. (2015), AHH is the share of the person equivalent allocated to the household, AHDW is the share of the household allocated to the dwelling and Rave is the average number of residents per dwelling. The first step in the allocation, from the world’s total carrying capacity to the equivalent carrying capacity of one person, is based on equality, i.e. an equal sized share to each person. The further allocation of the person equivalent to the dwelling could though be based on different approaches. In this study two methods for the allocation of the person equivalent is used; allocation based on economic value and allocation based on “Direct”“Indirect” Public
METHOD       23/74 current environmental burden. The allocation by economic value uses the current share that the specific activity or product represents of the GDP as allocation key, where the allocation by environmental pressure uses the current share of the total environmental impacts that the specific activity or product represents. For a discussion of the advantages and disadvantage of the two methods see section 5.1. For the economic allocation the Eurostat statistical bank was used as basis for the inventory data on household consumption. Inventories on the environmental pressures from household consumption are though far more ambiguous, and two main reports have been identified as sufficiently comprehensive to form the basis for the environmental allocation; one from the European Environmental Agency (EEA) and one from the European commission. The output of the reports vary, and the environmental allocation is therefor carried out first based on one and then the other, to identify the influence of definition of environmental pressure. The allocation is thus carried out with three different approaches: A. Economic value based on Eurostat statistics ( (BREEAM, 2015)2015) B. Environmental pressure based on a study by EEA (2013) C. Environmental pressure based on a study European commission (2006) All three base their definition of household categories on the COICOP categories defined by the United Nations Statistics Division (2015). The COICOP definitions will likewise form the basis for the allocation method and is described in Figure 10. The allocation is to the extent possible based on the boundary system described in section 3.2.2 to keep consistency between the allocated carrying capacity and the identified building impacts. Classification of individual consumption by purpose (COICOP) COICOP is a reference classification system developed by United Nations Statistics Division (United Nations, 2015). COICOP divides individual consumption expenditures according to their purpose incurred by households, non-profit institutions serving households and general government. The following 12 categories are relevant to household consumption: CP01 – Food and non-alcoholic beverages CP07 – Transport CP02 – Alcoholic beverages and tobacco CP08 – Communications CP03 – Clothing and footwear CP09 – Recreation and culture CP04 – Housing, water, gas, electricity and other fuels CP10 – Education CP05 – Furnishings, equipment and routine maintenance CP11 – Restaurants and hotels CP06 – Health CP12 – Miscellaneous goods and services Figure 10 Classification of indicidual consumption accordin to United Nations Statistics Division (United Nations, 2015)
  METHOD   24/74   3.4.1 A. Economic value When allocating according to economic value the allocation key will be identical for all environmental impact categories. To allocate the carrying capacity to the dwelling, the household consumption’s share of Gross Domestic Product (GDP) is firstly identified, then the distribution of household expenses within the COICOP categories is identified, see Table 5. Table 5 Household expenditure for Europe (Eurostat, 2015) Category Europe (EU-28) Household share of GDP2 57,1% Distribution of household expenses3 CP01 Food and non-alcoholic beverage 13% CP02 Alcoholic beverages, tobacco and narcotics 3,6% CP03 Clothing and footwear 5,2% CP04 Housing, water, electricity, gas and other fuels 24,1% CP05 Furnishing, equipment and routine maintenance 5,6% CP06 Health 3,7% CP07 Transport 13% CP08 Communications 2,6% CP09 Recreation and culture 8,7% CP10 Education 1,1% CP11 Restaurants and hotels 8,5% CP12 Miscellaneous goods and services 10,8% The two categories CP04 and CP05 represent all expenses related to the dwelling, however the categories also include non-related consumption such as electricity to appliances (TV, refrigerators etc.) as well as furnishing etc. See Table 6 for the subcategories of CP04 and CP05, which are related to the dwelling, the table also shows how large the share of a specific subcategory is allocated to the dwelling. Three subcategories need further allocation to deduct the non-relevant expenses namely 04.5.1, 05.1.2 and 05.3.1. All other subcategories listed in Table 6 are assumed to solely represent expenses directly related to life cycle expenses of the building. The repair and maintenance of the building are represented in the // 2 In 2013 3 In 2012
METHOD       25/74 subcategories 04.1.1 and 04.2.1 indirectly through the direct and imputed rentals. For an overview of the distribution in all sub-categories see appendix J. Table 6 Subcategories of CP04 and CP05 relevant to the dwelling Category Comments % of category To dwelling CP04 – Housing, water, electricity, gas and other fuels 04.1.1 – Actual rentals paid by tenants For main residence 19,3% 100% 04.2.1 – Imputed rentals of owned occupiers For main residence 51,1% 100% 04.5.1 – Electricity All electricity used 7,1% 29%4 04.5.2 – Gas All gas used 3,9% 100% 04.5.3 – Liquid fuels Domestic heating and lighting oils 1,9% 100% 04.5.4 – Solid fuels Coal, coke, firewood and the like 0,6% 100% 04.5.5 – Heat energy District heating, incl. hire of meters etc. 1,4% 100% Total of category to dwelling 80,1% CP05 – Furnishings, household equipment and routine household maintenance 05.1.2 – Carpets and other floor coverings Loose carpets, fitted carpets, linoleum and the like. 5,4% 40%5 05.3.1 – Major household appliances Air conditioners, space- and water heaters, refrigerators, freezers etc. 10,1% 40%6 Total of category to dwelling 6,2% Based on the economic allocation the share of the person equvivalent capacity in all impact categories allocated to the dwelling is thus: Aeco = 57% * (24,1%*80,1% + 5,6%*6,2%) = 11,2% // 4 Share of a household’s electricity consumption related to building operation (SBI, 2008) 5 Share from appliances related to building operation (e.g. space- and water heater) is assumed to be 40% 6 Share related to solid flooring (e.g. wood flooring) is assumued to be 40%
  METHOD   26/74   Table 7 Allocation of carrying capacity to respectively the entire household and to the building. For all impact categories. Europe (EU-28) To household [% of total] 57,1% To dwelling [% of household] 19,7% To dwelling [% of total] 11,2% 3.4.2 Allocation by current environmental pressure (B+C) The following section will try to identify the share of carrying capacity that can be allocated to the dwelling, if the allocation is based on the dwelling’s current environmental impacts. The allocated share in an impact category will thus corresponds to the dwelling’s percentage wise current impact in that category. For instance if assumed the dwelling represents 20% of the total climate change impact from the household, then 20% of the climate change capacity is allocated to the dwelling. To allocate according to the environmental pressure from a building in relation to other products and services is more comprehensive than to identify and allocate according to the economic value it represents. The current section is based on two primary studies in this field, namely the report Environmental pressure from European consumption and production from the EEA (2013) and Environmental Impacts of products (EIPRO) and associated appendices by the European Commission Joint research centre (2006), see Figure 11 for further description. The approach in the studies varies, and the environmental pressures found for different categories are not identical. To identify if one study over the other would be more applicable in the current allocation scenario would require a comprehensive knowledge and insight into the two studies. The following allocation is carried out twice first based on the one method and then the other. According to a Swiss study by the Federal Office for the Environment (FOEN, 2011) the direct emissions in CO2 equivalents from Swiss households covers 39% of the total CO2 equivalents emitted by Switzerland. In the current study this relation between household emissions and total emissions is assumed identical when indirect emissions are accounted for. Further more Switzerland is assumed representative for the European relation between household and total emissions, why 39% of the person equivalent carrying capacity allocates to the private household. This allocation to household will be applied to all impact categories for both the allocation according to the EEA report as well as the EIPRO report.
METHOD       27/74 B. European Environmental Agency (EEA) C. European Comission (EIPRO) Title: Environmental pressure from European consumption and production Published: 2013 Title: Environmental impact of produts (EIPRO) Published: 2006 Description: The study identifies the hotspots and leverage points in European consumption and production. The study uses an environmentally extended input- out put analysis, and in the consumption perspective this includes all environmental pressures caused directly or indirectly by national consumption. The study focuses on environmental pressure caused by air emissions and material flows, based on data from Eurostat. The environmental impacts are identified as: • Emissions of GHG • Acidifying emissions • Emissions of Tropospheric ozone forming precursors • Material flow Description: The study identifies the products having the greatest environmental impact throughout the life cycle. For this purpose a new input-output model was developed, covering the environmental impact of all products consumed in EU-25 (produced and imported), including the life cycle stages of extraction, transport, production, use and waste management. The environmental impacts are identified as: • Abiotic depletion • Acidification • Ecotoxicity • Global warming • Eutrophication • Human toxicity • Ozone layer depletion • Photochemical oxidation Figure 11 Description of the two environmental studies forming the basis for the two allocation scenarios according to environmental pressure (EEA, 2013; European Commission, 2006) 3.4.3 Allocation based on EEA (B) The study from the EEA (2010) identified the environmental pressure from the average European (EU-28) household consumption based on the COICOP categories, see Figure 10 for description of the COICOP categories. The environmental pressure has been identified in four impact categories; Greenhouse gas emissions, acidifying emissions, tropospheric ozone precursors and material use. Based on these four categories a category averaging the four has been created, which will be applied to the impact categories of Bjørn et al. (2015) that is not covered by the initial four, see Table 8 for the distribution in all five categories.
  METHOD   28/74   Table 8 Relative impact of the COICOP main categories in the five impact categories (EEA, 2013) GHG emissions Acidifying emissions Trophosperic ozone precursor Material use Average The environmental pressure from the different COICOP categories is seen to vary from impact category to impact category, see Table 8. The impact from CP04 Housing, water, electricity, gas and other fuels is for example seen to vary from 14% of household impact from acidifying emissions to 36% from greenhouse gas emissions. 17%   36%   11%   24%   4%   43%   14%   9%   22%   6%   17%   25%   11%   38%   3%   34%   27%   14%   12%   6%   28%   26%  11%   24%   5%  
METHOD       29/74 Table 9 Application of impact categories from EEA (2013) to impact categories from Bjørn & Hauschild (2015). The “Average” category is an average of the four EEA cateogires, and applied when no EEA cateogry is defined. Application of impact categories from EEA (2013) to those from Bjørn & Hauschild (2015) EEA category Bjørn & Hauschild category Acidification è Terrestrial acidification Average è Terrestrial eutrophication Material use è Water depletion Material use è Land use, soil erosion Material use è Land use, biodiversity Global warming è Climate change Average è Ozone depletion Average è Freshwater eutrophication Average è Marine eutrophication Tropospheric ozone precursors è Photochemical ozone formation Average è Freshwater ecotoxicity As previous the categories CP04 and CP05 are further allocated, since not all impacts included is related to the dwelling (i.e. furnishing, household equipment etc.). Due to lack of information on the distribution of environmental pressure of the subcategories in the report, the allocation from the COICOP main categories (CP04 and CP05) to the subcategories (CP04.1.1, CP04.2.1 etc) is based on the economic distribution identified in the previous section, see Table 6 and not on environmental pressure. The study from Bjørn & Hauschild (2015) identifies the carrying capacity in 11 impact categories but the study from EEA (2013) only identifies the distribution of environmental burden in five categories (including the average). The allocation of the carrying capacity is carried out according to the EEA impact category found the most appropriate, see Table 9, i.e. Terrestrial eutrophication is allocated according to the environmental impact from the Average category and Water depletion according to material use. The final allocation of carrying capacity to the building in the 11 impact categories is seen to vary from 4,6% in Terrestrial acidification to 11,5% in Climate change, see Table 10.
  METHOD   30/74   Table 10 Allocation of carrying capacity based on current environmental pressure. Where environmental pressure is defined according to European Environmental Agency (2013) Europe (EU-28) Household [% of total] 39% Dwelling [% of total] Terrestrial acidification 4,6% Terrestrial eutrophication 8,2% Water depletion 8,8% Land use, soil erosion 8,8% Land use, biodiversity 8,8% Climate change 11,5% Ozone depletion 8,2% Freshwater eutrophication 8,2% Marine eutrophication 8,2% Photochemical ozone formation 8,1% Freshwater ecotoxicity 8,2% 3.4.4 Allocation based on EIPRO (C) The EIPRO study from the European commission (2006) is a bit older than the EEA study (2013), but it’s a comprehensive study including a comparative analysis of method and findings in other relevant studies. The EIPRO study identifies the environmental pressure in eight impact categories, from which seven of them are relevant in the current study. The EIPRO study takes its basis in the general COICOP definitions as the EEA study, but in contrast to the EEA study, EIPRO actively consider the content of the categories and moves impact from one category to another. For instance the household electricity is in the COICOP definitions all gathered in the subcategory CP04.05 Electricity, gas and fuels (in CP04), but the EIPRO study couples the electricity consumption with relevant activity, so i.e. electricity for cooking is accounted for in the Food category.
METHOD       31/74 Table 11 Relative impact of the COICOP main categories in the seven impact categories (European Commission, 2006) Global warming Acidification Photochemical oxidation Abiotic depletion Eutrophication Ecotoxicity Ozone layer depletion 31%   24%   18%   6%   9%   5%   31%   2%   26%   14%   7%   10%   6%   27%   3%   22%   20%   7%   9%   7%   22%   35%   20%   5%   7%   5%   60%   4%   10%   6%   3%   13%   34%   6%   20%   15%   7%   9%   6%   25%   3%   21%   4%   14%   11%   9%   10%  
  METHOD   32/74   The environmental pressure from the joint category CP04-05 Housing, furniture etc. is seen to vary from 35% of the total household impact from acidification to only 10% from eutrophication. The allocation key in the different categories is applied to the 11 categories from Bjørn & Hauschild (2015) according to Figure 12. In the EIPRO study the content of the subcategories is defined for only four of the seven impact categories; Acidification, Eutrophication, Global warming and Photochemical oxidation. An average category is therefore created, and the application of the subcategories to the main categories is also seen from Figure 12. Application of impact categories from the European Commission (2006) to those from Bjørn & Hauschild (2015) Bjørn & Hauschild EIPRO Main category Subcategory Terrestrial acidification è Acidification è Acidification Terrestrial eutrophication è Eutrophication è Eutrophication Water depletion è Abiotic depletion è Average Land use, soil erosion è Abiotic depletion è Average Land use, biodiversity è Abiotic depletion è Average Climate change è Global warming è Global warming Ozone depletion è Ozone layer depletion è Average Freshwater eutrophication è Eutrophication è Eutrophication Marine eutrophication è Eutrophication è Eutrophication Photochemical ozone formation è Photochemical oxidation è Photochemical oxidation Freshwater ecotoxicity è Ecotoxicity è Average Figure 12 Application of impact categories from the European Comission (2006) to impact categories from Bjørn & Hauschild (2015). The “average” category is an average of the four subcategories and is applied to the main cateogires when no subcategory distribution were stated in EIPRO. As previously described the EIPRO study has not strictly kept to the definitions of the subcategories. From Table 12 the subcategories relevant to the building in the impact category Global warming is shown together with information on their share of the category. For all sub-cateogires and the distribution of environmental pressure in the four impact categories see appendix K.
METHOD       33/74 Table 12 Distribution of subcategories for Global waming CP04 +CP05 Housing etc. % of category Alloc. To building A257 (Heating with) heating equipment, except electric and warm air 19,9% 100% A31 New residential 1unit structure, nonfarm 13,6% 100% A33 New additions and alterations, nonfarm, construction 7,6% 100% A42 Maintenance and repair of farm and nonfarm residential structure 3,0% 100% A149 Partitions and fixtures, except wood 1,3% 100% A334 (use of) electric housewares and fans 0,8% 100% A25 Crude petroleum and natural gas 0,8% 100% Total of category to dwelling 47% Based on the allocation of the environmental impact to the main categories of housing, and then again to the subcategories relevant to the dwelling the final share of the carrying capacity in the 11 impact categories is identified, see Table 13. The allocation share is seen to vary from only 1,3% in Eutrophication (marine, freshwater and terrestrial) to 5,6% abiotic depletions such as water and land use. Table 13 Allocation of carrying capacity in the 11 impact categories from Bjørn & Hauschild (2015) based on the EIPRO study (European Commission, 2006) Europe (EU-28) Household [% of total] 39% Dwelling [% of total] Terrestrial acidification 3,4% Terrestrial eutrophication 1,3% Water depletion 5,6% Land use, soil erosion 5,6% Land use, biodiversity 5,6% Climate change 4,3% Ozone depletion 3,3%
  METHOD   34/74   Freshwater eutrophication 1,3% Marine eutrophication 1,3% Photochemical ozone formation 4,3% Freshwater ecotoxicity 3,3% 3.4.5 Resume of findings The three allocation scenarios have led to three suggestions for the share of the person equivalent carrying capacity that could be allocated to the dwelling, see Table 14. The allocation according to economic value (A) is in all impact categories except GWP seen to allocate a greater share of the carrying capacity to the dwelling than the other two scenarios (B+C). In general it is seen that scenario C allocates least of the carrying capacity to the dwelling in all impact categories. Table 14 Allocation of the total carrying capacity to the dwelling based on three approaches A, B and C. CC = carrying capacity. All figures of carrying capacity are in person equivalent. A. Economic B. Emission EEA C. Emission EIPRO Terrestrial acidification 11,2% 4,6% 3,4% Terrestrial eutrophication 11,2% 8,2% 1,3% Water depletion 11,2% 8,8% 5,6% Land use, soil erosion 11,2% 8,8% 5,6% Land use, biodiversity 11,2% 8,8% 5,6% Climate change 11,2% 11,5% 4,3% Ozone depletion 11,2% 8,2% 3,3% Freshwater eutrophication 11,2% 8,2% 1,3% Marine eutrophication 11,2% 8,2% 1,3% Photochemical ozone formation 11,2% 8,1% 4,3% Freshwater exotoxicity 11,2% 8,2% 3,3% The economic allocation method (A) is chosen to form the basis of the following analyses. None of the methods is though more correct than the others, the economic allocation is used solemnly due to it being the more generally accepted and used allocation method.
METHOD       35/74 3.5 Sensitivity analysis The determination of the environmental carrying capacity as well as the determination of the total environmental impacts from the building is subjects to uncertainties. A sensitivity analysis is carried out in order to identify the effects of deviations in both the carrying capacity and the building impacts determination. The sensitivity analysis is carried out on the Standard house based on the three scenarios illustrated in Table 15, and where scenario 1 is based on the current calculations of both carrying capacity and building impacts. Table 15 Specification of the scenarios deviation from the impacts and capacity asumptions used as analyses basis Carrying capacity Building impacts Scenario 1 - - Scenario 2 -15% +15% Scenario 3 +15% -15%
  METHOD   36/74  
RESULTS       37/74 4 RESULTS In the following section the results from the analyses is displayed and shortly described. In the analyses it was found that the impact on Land use – erosion was immensely transgressed in all cases. For the standard house for instance the impact in this category was seen to exploit 9.989.527% of the carrying capacity. The land use characterization factors contain great assumptions, and great variations in the results were expected. However due to the immense variations, the impact category have been excluded from the result display and further analyses, since the methodology is assumed in the need of further improvement before applied in the absolute sustainability assessment. 4.1 Carrying capacity for a single-family house The average number of residents per single-family houses in Denmark is 2,6 persons (Statistic Denmark, 2015). Based on this number the carrying capacity of a single-familty house is shown in Table 16. Table 16 Carrying capactiy (allocated according to economic value) per dwelling when the average number of residents is 2,6. Annual carrying capacity per single-family house – 2,6 person per dwelling Terrestrial acidification (AP) 670 mole H+ eq. Water depletion 89 m3 Land Use Erosion 0,52 ton eroded soil Biodiversity 4369 m2 *year Climate change (GWP) (Temperature) 287 kg CO2 eq. (Radiative forcing) 152 kg CO2 eq. Ozone depletion (ODP) 0,02 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,13 kg P eq. Marine 9 kg N eq. Terrestrial 815 mole N eq. Photochemical oxidant formation (POCP) 14 kg NMVOC Freshwater ecotoxicity 2912 PAF*m3 *day
  RESULTS   38/74   4.2 Current environmental pressure from dwellings In the following the impacts from current building practice related to the carrying capacity are presented based on the two reference buildings, namely the Standard house representing current prevalent construction methods and the Upcycle house representing one of the extremes when come to reducing environmental impact from material use. 4.2.1 Standard house (128m2 ) From Table 17 the resulting impact per year from the standard house is shown both including and excluding the impact from the operational energy in the buildings use phase. Table 17 Standard house (128m2 ) annual impacts including (incl) or excluding (excl) use phase energy. Building lifetime 50 years Annual impacts, Standard house – 128m2 , building lifetime 50 year Incl. Excl. Terrestrial acidification (AP) 178 83 mole H+ eq. Water depletion 66 23 m3 Land Use Erosion 52370 920 ton eroded soil Biodiversity 1055 357 m2 *year Climate change (GWP) 2376 1047 kg CO2 eq. Ozone depletion (ODP) 0,0002 0,0001 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,70 0,22 kg P eq. Marine 0,58 1 kg N eq. Terrestrial 90 41 mole N eq. Photochemical oxidant formation (POCP) 8 3 kg NMVOC Freshwater ecotoxicity 2723 1206 PAF*m3 *day The resulting impacts from the standard house shown in Table 17 are then related to the carrying capacity derived in section 4.1 to illustrate the percentage of the carrying capacity depleted by the house, which is here referred to as an absolute sustainability assessment, see Figure 13.
RESULTS       39/74 Absolut sustainability assessment - Standard house (Incl. use phase energy) - IN,B Acidification, terrestrial 27% Water depletion 74% Land use Erosion - Biodiv. 24% Climate change Temp. 828% Rad. Forc. 1563% Ozone depletion 0,7% Eutrophication Freshwater 524% Marine 6% Terrestrial 11% Ozone formation 57% Freshwater ecotoxicity 94% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area. LEK2015 Figure 13 Absolute sustainability assessment of the standard house including use phase energy From the absolute sustainability assessment illustrated in Figure 13 it seems evident how impacts from the standard house exceeds the carrying capacity with immense lengths in terms of both freshwater eutrophication and climate change. The freshwater eutrophication on 0,7 kg P eq. exceeds the capacity by more than a factor 4 demanding a reduction of more than 80% to stay within the carrying capacity. The climate change impact amounting to 2376 kg CO2 eq. is exceeding the capacity by a factor of 15. The reduction on climate change impact is thus seen call for a reduction up to 94%. In addition to the two impact categories were the capacity has already been transgressed additional two categories are seen near to the boundaries. The freshwater exotoxicity of 2723 PAF*m3 *day is seen to exploit 94% of the capacity together with the water depletion of 66m3 which is exploit 74% of the capacity. If the impacts are grouped according to life cycle stages, the use phase is seen to represent more than 50% in all impact categories except for the two land use categories, see Figure 14. When it comes to climate change the use phase is seen to represent almost 60%, and from which the 56% comes from energy consumption for operating the building and the rest from replacements and repair.
  RESULTS   40/74   This indicates that nearly 44% of the impact is derived from material use and construction of the building. From Figure 15 it shows how the roof, the outer walls and the ground slab contributes significantly to the resulting impact, but also Doors and windows are seen to contribute considerably. Important to notice is also the impact from energy used for constructing the building, which is not insignificantly. On i.e. GWP it contributes with more than 10% of the impact. -­‐20%   0%   20%   40%   60%   80%   100%   Production   Construction   Use  phase   EoL   Site   Figure 14 GWP contribution from life cycle stages (incl. site occupation and transformation) for the Standard house. Over a 50year period. 0%   10%   20%   30%   40%   50%   60%   70%   80%   90%   100%   Doors  and  windows   Floors  and  surfaces   Foundation   Ground  slab   Inner  walls     Installations   Outer  walls   Roof   Const.  Energy   Figure 15 GWP impact distribution from the standard house over a 50 year period excluding use phase energy and impacts related to the site.
RESULTS       41/74 4.2.2 Upcycle house The heated area of the Upcycle house is not as big as the area of the standard house. The size of a building is naturally of great importance to the resulting environmental impacts, and the more square meters the bigger resulting impact. Therefore the environmental impact of the Upcycle house is presented both in its original size (104m2 ) but also in a size corresponding to the size of the standard house (128m2 ). Both houses are expected to house an equal size family, and the fewer square meters of the Upcycle house is therefor considered to be a result of an improved functionality of the house. The better utilization of the built area is credited when presenting the resulting impact according to the original size, where the presentation of the impact when the size is equal to the standard house allows for a direct comparison of the upcycled building style vs. the more common. 4.2.2.1 Original building area (104m2 ) From Table 18 the resulting impacts per year from the Upcycle house with the original size of 104m2 are shown both including and excluding the impact from the operational energy in the buildings use phase. Table 18 Upcycle house (104m2 ) impact per year including (incl) or excluding (excl) use phase energy . Building lifetime 50years Annual impact from the Upcycle house – 104m2 , building lifetime 50 year Incl. Excl. Terrestrial acidification (AP) 124 48 mole H+ eq. Water depletion 44 9 m3 Land Use Erosion 42113 311 ton eroded soil Biodiversity 743 175 m2 *year Climate change (GWP) 1373 293 kg CO2 eq. Ozone depletion (ODP) 0,0001 0,00003 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,5 0,1 kg P eq. Marine 0,4 0,1 kg N eq. Terrestrial 60 21 mole N eq. Photochemical oxidant formation (POCP) 5 2 kg NMVOC Freshwater ecotoxicity 2053 821 PAF*m3 *day As in the previous case the absolute sustainability assessment is also applied to the impacts from the Upcycle house, which appears in Figure 16.
  RESULTS   42/74   Absolute sustainability assessment - Upcycle house (including use phase energy) - IN,B Acidification, terrestrial 19% Water depletion 50% Land use Erosion - Biodiv. 17% Climate change Temp. 479% Rad. Forc. 903% Ozone depletion 0,4 Eutrophication Freshwater 369% Marine 4% Terrestrial 7% Ozone formation 38% Freshwater ecotoxicity 70% Comments: All impacts included. Building lifetime, 50 years. 104m2 heated area. LEK2015 Figure 16 Absolute sustainability asessment of the upcycle house (104m2 ) including usephase energy From Figure 16 it shows how the impacts from the Upcycle house also transgress the boundaries of the carrying capacity with immense lengths both for freshwater eutrophication and climate change. The yearly impact on freshwater eutrophication on 0,5 kg P eq. exceeds the carrying capacity by nearly a factor 3, requiring a further reduction on 74%. Climate change on the other hand is impacted yearly with 1373 kg CO2 eq. from the Upcycle house, which exceeds the carrying capacity by a factor. The need for reduction would then correspondingly be 89%. Apart from the transgression of Climate change and freshwater eutrophication only freshwater ecotoxicity is seen approaching the boundary with an impact corresponding to 70% of the carrying capacity. The resulting impacts are reduced from the Upcycle house because of the use of upcycled materials leading the constant use phase energy to represent a larger share of the summarised impacts, see Figure 17.
RESULTS       43/74 When it comes to the use phase energy, the impact on GWP is 1080 kg CO2 eq. per year out of the total GWP impact of 1373 kg CO2 eq.. The use phase energy is thus seen representing 79% of the total impact, where on the Standard house the use phase energy only represented 56% of the total impact. -­‐20%   0%   20%   40%   60%   80%   100%   Production   Construction   Use  phase   EoL   Site   Figure 17 GWP contribution from life cycle stages (including site occupation and transformation) for the Upcycle house. Over a 50 year period. -­‐20%   0%   20%   40%   60%   80%   100%   Doors  and  windows   Floors  and  surfaces   Foundation   Ground  slab   Inner  walls     Installations   Outer  walls   Roof   Terrace  and  greenhouse   Const.  Energy   Figure 18 Impact distribution from the Upcycle house over a 50 year period excluding use phase energy and impacts related to the site.
  RESULTS   44/74   From Figure 18 it shows how impact from energy for construction of the house plays a more significant role in the Upcycle house than what was the case with the Standard house. The construction energy alone is seen to represent around 35% of the total impact on climate change as well as water depletion, and around 25% of the total when it comes to freshwater eutrophication. The impacts from installations are seen to increase compared to the standard house, which is due the general decrease in the impact from material and construction on the Upcycle house. 4.2.2.2 Building area equal to the standard house If the size of the Upcycle house instead is increased to 128m2 equal to that of the Standard house, allowing for a more direct comparison of the advances of the upcycled materials, the resulting annual impact of the building are illustrated in Table 19. Table 19 Upcycle house (128m2 ) impact per year including (incl) or excluding (excl) use phase energy . Building lifetime 50years Annual impact from the Upcycle house – 128m2 , building lifetime 50 year Incl. Excl. Terrestrial acidification (AP) 153 59 mole H+ eq. Water depletion 54 11 m3 Land Use Erosion 51831 382 ton eroded soil Biodiversity 914 216 m2 *year Climate change (GWP) 1690 361 kg CO2 eq. Ozone depletion (ODP) 0,0001 0,00003 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,6 0,1 kg P eq. Marine 0,5 0,1 kg N eq. Terrestrial 74 25 mole N eq. Photochemical oxidant formation (POCP) 6,4 2 kg NMVOC Freshwater ecotoxicity 2527 1010 PAF*m3 *day
RESULTS       45/74 Absolute sustainability assessment - Upcycle house (all) - IN,B Acidification, terrestrial 23% Water depletion 61% Land use Erosion - Biodiv. 21% Climate change Temp. 589% Rad. Forc. 1111% Ozone depletion 0,5 Eutrophication Freshwater 454% Marine 5% Terrestrial 9% Ozone formation 47% Freshwater ecotoxicity 87% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area Figure 19 Absolute sustainability asessment of the Upcycle house (128m2 ) including use phase energy The additional 24m2 added to the Upcycle house to make it comparable to the Standard house are seen to contribute with an additional 317 kg CO2 eq. per year as well as an extra 0,1 kg P. eq. when considering the two categories already exceeding the carrying capacity. This gives a total transgression of the climate change category by a factor 5 to 10 requiring a reduction of 83% to 91% depending on the capacity definition. On the freshwater eutrophication the transgressions is seen to be around a factor 4 requiring a decrease of an extra 78% to reach below the capacity. The impacts from the Upcycle house correspond to a decrease of 29% on GWP when compared to the impact from the standard house. When it comes to the freshwater eutrophication the impact corresponds to a 14% reduction. The reduction in GWP and freshwater eutrophication are seen to not just contribute to an increased impact in the remaining categories, implying that the reductions are not at the expense of a burden shift.
  RESULTS   46/74   4.3 Use phase energy In the following the effects of decreased energy consumption in the use phase is illustrated. 4.3.1 Standard house When the energy consumption is decreased from LEK2015 to BK 2020 the transgression of the climate change boundary is seen reduced with around 25% and the transgression of the freshwater eutrophication with around 30%. The transgression is though still seen to be 1052% for climate change and 354% for freshwater eutrophication. Even if the use phase energy is zero, implying that the building has no energy consumption throughout the lifetime, the transgression is still immense 589% on climate change and 63% on freshwater eutrophication. The use phase energy is seen to contribute with 56% of the total climate change impact when energy class LEK2015 is used, and around 40% when using energy class BK2020. Absolute sustainability assessment - Standard house (various energy consumption) - IN,B Br 2015 Br 2020 None Terrestrial acidifiation 27% 20% 12% Water depletion 74% 51% 26% Land use Erosion - - - Biodiv. 24% 24% 8% Climate change Temp. 828% 610% 365% Rad. for. 1563 % 1152 % 689% Ozone depletion 0,7% 0,6% 0,4% Eutrophi- cation Freshwat. 524% 354% 163% Marine 6% 4% 11% Terrest. 11% 8% 5% Ozone formation 57% 42% 24% Freshwater ecotoxicity 94% 69% 41% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area LEK2015 BK2020 No Use phase energy Figure 20 Absolute sustainability asessment of the Standard house (128m2 ) with various energy consumption
RESULTS       47/74 4.3.2 Upcycle house For the Upcycle house the change from energy class LEK2015 to BK2020 is seen to reduce the climate change impact with 37%, though still with a transgression of the carrying capacity of 271-601%. On the freshwater eutrophication the reduction is also 37%, but with a transgression of 184% when the energy consumption is reduced to BK2020. When the use phase energy is assumed non-existent the impact on climate change is still seen to exceed the carrying capacity, but now with only 26-137%, and freshwater eutrophication is seen to stay just within the carrying capacity. The use phase energy is seen to constitute with 79% of the climate change impact when the energy class is LEK2015, but 66% when the energy class is BK2020. Absolute sustainability assessment - Upcycle house (various energy consumption) - IN,B Br 2015 Br 2020 None Terrestrial acidifiation 23% 16% 12% Water depletion 61% 38% 13% Land use Erosion - - - Biodiv. 21% 20% 5% Climate change Temp. 589% 371% 126% Rad. for. 1111 % 701% 237% Ozone depletion 0,5% 0,3% 0,1% Eutrophi- cation Freshwat. 454% 284% 93% Marine 5% 3% 1% Terrest. 9% 6% 3% Ozone formation 47% 31% 14% Freshwater ecotoxicity 87% 62% 35% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated a Energy consumption according to the Danish building regulations class 2015 and 2020, and excluding use phase energy. LEK2015 BK2020 No use phase energy Figure 21 Absolute sustainability asessment of the Upcycle house (128m2 ) with various energy consumption
  RESULTS   48/74   4.4 Building lifetime To identify the effect of an increased lifetime the LCA on both Standard house and Upcycle house have been carried out with a building lifetime of respectively 50 years and 120 years. With the increased lifetime of 120 years any potential modifications of the buildings have not been accounted for. The prolonged lifetime will only affect the impact from materials, and use phase energy is therefore not included in the following. For the following parametric variations, only key findings are summarized. For a full result display see appendix G. 4.4.1 Standard house When looking at the impact from materials and construction Table 20 shows how the prolonged lifetime from 50 to 120 years decreases the yearly impact on climate change by 43%. When looking at freshwater eutrophication the yearly decrease is seen to be 33%. Table 20 Yearly mpact from material and construction in the Standard house normalised according to carrying capacity, with a building lifetime of 50 or 120 years. 50 year lifetime 120 year lifetime Climate change Temperature 365% 207% Radiative forcing 690% 391% Freshwater eutrophication 163% 109% Se appendix G for a full result display. 4.4.2 Upcycle house When looking at the Upcycle house the prolonged lifetime is seen to affect the yearly impact on climate change by a reduction of 40%. For the freshwater eutrophication the decrease is seen to be around 30%. Table 21 Yearly mpact from material and construction in the Upcycle house normalised according to carrying capacity, with a building lifetime of 50 or 120 years. 50 year lifetime 120 year lifetime Climate change Temperature 126% 76% Radiative forcing 237% 143% Freshwater eutrophication 93% 67% Se appendix G for a full result display.
RESULTS       49/74 4.5 Validation of model build-up It is important to note that the resulting impacts from the project models displayed in this section are not representative for the absolute impact of the buildings used in the project, since the project models for this section have been alternate to represent the same methodological approach as used by the SBI to create a basis of comparison. 4.5.1 Standard house From Table 22 the resulting impacts in the five categories; global warming potential (GWP), ozone depletion (ODP), photochemical ozone creation (POCP), acidification (AP) and eutrophication (EP) are shown. The deviation regarding the GWP is +15%, but when it comes to the remaining four impact categories, the deviations are seen to be remarkable higher. The deviations in the remaining four impact categories are ranging between +75% for AP up to +388% for EP. Table 22 Resulting impacts for a 120 year period of the Reference house according to SBI and the current project model, when prerequisites are approximately the same SBI Model Deviation GWP [kg CO2eq] 55.200 63.492 +15% ODP [kg R-11eq] 0,002 0,0058 +190% POCP [kg Ethene eq.] 20,8 41,7 +100% AP [kg SO2eq] 236 409 +74% EP [kg PO4eq] 26,1 101 +388% From Figure 22 the relative impact in the different categories is illustrated for the SBI model, and in Figure 23 for the current project model.
  RESULTS   50/74   Reference house – SBI 120 year period Reference house – Model 120 year period k From Figure 22 and Figure 23 the impact distribution between the building parts in the two models is seen fairly alike. There are though some differences, which is partly due to differences in the grouping of construction parts. The category “Floors and surfaces” in the altered absolute project model does not exist in the SBI-model, but assumed mainly to be included in the “Inner walls “category in the SBI model. Further more there are deviations when it comes to windows and doors, which in the absolute model is group in one category, but in the SBI model the category only includes windows, and doors would thus be included in an other category in the SBi model, ie. “inner walls” or “outer walls”. There are though some variations seen in ie. Groundslabs impact in POCP as well as the installations impact in AP and EP. 4.5.2 Upcycle house Since only the GWP is quantified in the SBI report (SBI, 2013) dealing with the Upcycle house this is the only impact category the Upcycle house will be validated according to. From Table 23 shows how the resulting GWP of the model is 100% higher than the impact from the SBI analyses. Table 23 Resulting GWP over a 50 year period for the Upcycle house according to SBI and the current model, based on equal prerequisites SBI Model Deviation GWP total [kgCO2eq/m2 /yr] 0,7 1,4 +100% To create a clearer picture of the reason for the large deviation the resulting GWP is identified for the individual construction parts, see Figure 22 Contribution of the construction parts of the SBI model (SBI, 2015) Figure 23 Contribution of construction parts of the project model Installations Windows Inner walls Roof Outer walls Ground slab Columns and beams Foundations
RESULTS       51/74 Graph 1. The figure shows, how the greatest relative deviations is seen on the Inner surfaces, the roof and the inner walls. Common for these three construction parts is that they are all primarily constituted by timber based products such as OSB, paperwool and structural timber. For the inner surfaces timber based products constitutes 60% of the mass, for the inner walls it is 54% of the mass and for the roof it constitutes a total of 73%. Graph 1 GWP displayed on construction parts for respectively the project model and the SBI model 4.6 Sensitivity analysis From Figure 24 the effects of a deviation on +/- 15% on the carrying capacity combined with a deviation of +/- 15% on the building impacts is illustrated. Scenario 2 increases the climate change pressure from a factor 15 transgression of the capacity to a factor 20, as well as the freshwater eutrophication from a transgression of the capacity of a factor 4 to a transgression of a factor 6. Further more water depletion and freshwater ecotoxicity is pushed over the line and scenario 3 thus causes an exploitation of 100% of the water capacity and a 27% transgression of the freshwater ecotoxicity capacity. From scenario 3 the transgression on the climate change capacity is seen decreasing from a factor 15 to a factor 10, and the transgression of freshwater eutrophication is seen decreased from a factor 4 to a factor 3. The water depletion is seen decreasing from an exploitation of 74% of the capacity to 55% of the capacity, and the pressure on freshwater ecotoxicity is seen decreasing from an exploitation of 94% of the capacity to 69%. -­‐4000   -­‐2000   0   2000   4000   6000   8000   10000   [kgCO2]   GWP  of  120-­‐year  period   Model   SBI  
  RESULTS   52/74   Absolute sustainability assessment - Sensitivity analysis, Standard house - I/C Sc.1 Sc2 Sc3 Terrestrial acidifiation 27% 36% 20% Water depletion 74% 100% 55% Land use Erosion - - - Biodiv. 24% 33% 18% Climate change Temp. 828% 1120 % 612% Rad. for. 1563 % 2114 % 1155 % Ozone depletion 0,7% 0,9% 0,5% Eutrophi- cation Freshwat. 524% 710% 388% Marine 6% 9% 5% Terrest. 11% 15% 8% Ozone formation 57% 77% 42% Freshwater ecotoxicity 94% 127% 69% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area I/C = Impact relative to carrying capacity Scenario 1: Carrying capacity and building impacts identical to the general analysis Scenario 2: -15 carrying capacity and +15% building impacts Scenario 3: +15% carrying capacity and -15% building impacts Scenario 2 Scenario 1 (basis) Scenario 3 Figure 24 Sensitivity analsysis illustrating the effects of a +/- 15% change in carrying capcity calculation and +/- 15% in building impact assessment
DISCUSSION       53/74 5 DISCUSSION 5.1 Allocation of the carrying capacity The definition of the share that should be allocated from the total carrying capacity to the building would probably differ depending on the eyes seeing. People engaged in the construction industry would most likely find it bigger than people engaged in other industries, and again policymakers, financiers, sociologist and so on might have different views on what this “fair share” looks like. A clear and definite answer to the definition of this “fair share” allocated to the building might therefor be non-existent, and the approaches used in this study are just some of many possible. Three approaches to the allocation of the carrying capacity were used in the study, with all three initially based on the person equivalent carrying capacity identified for the World by Bjørn & Hauschild (2015). One approach allocated the person equivalent carrying capacity by economic value and two allocated it by current environmental pressure. The allocation by economic value assigned an equal share of all impact categories to the building based on its economic share of a person’s household economy, where the allocation based on environmental impact varied from impact category to impact category. The economic allocation is somewhat more straightforward than the allocation based on environmental pressure. The inventories on household economy are comprehensive and available in national or international statistical databanks such as Eurostat or Statistic Denmark. An identification of the buildings economic part of the household economy is therefor relatively forthright. The economic allocation though assigns an equal share of the carrying capacity to all impact categories, regardless of the fact that some products and services would have a natural diversity in environmental pressure from impact category to impact category. Agriculture would for instance tend to have a relatively larger impact on the nitrogen- and phosphors cycles than what would be expected from the building industries. It could therefore be wise to assign a larger share of the carrying capacity to the agricultural industry than to the building industry even if assumed representing the same economic value. When on the other hand allocating according to the current environmental pressure the process of identifying the buildings share of the household’s impact is more complex. The environmental pressures from the ng household consumption is not as unequivocal identified as for the economic value, and for that reason the allocation method have been carried out based on two scientific reports with diverse output results. When
  DISCUSSION   54/74   dealing with environmental pressures the boundaries becomes more blurred and one study might include indirect effects that another study ignores, and identifying if one background report is more accurate than the other requires a comprehensive knowledge an insight into the studies. Another downside to the allocation based on current pressures is the fact that the allocation method can tend to punish industries, services etc. that have already reduced their impact immense. These industries or services will have a smaller share of the capacity allocated than for industries or services with a currently high environmental pressure. When looking at the carrying capacity allocated to the building in the impact category climate change the three allocation methods resulted in an allocation of 11,2% when using the economic allocation and an allocation of 11,5% respectively 4,3% when using the current environmental pressure based on EEA and EIPRO. The impact category where the variation in allocated share differs the most, when comparing allocation method, is the eutrophication categories. The share is seen varying from 1,3% when allocating according to environmental pressure based on EIPRO reaching 11,2% when based on the economic allocation. All three methods used are though based on the person equivalent carrying capacity implying that an equal share of the world’s capacity is initially allocated to each citizen of the world implying a fundamental equal distribution of the world’s resources. One could argue that a fully economic or environmental allocation would be more accurate, implying that for example a fully economic allocation of the world’s capacity is based on an initial allocation of the capacity to each country based on GDP. Countries with a low GDP per citizen would then have a smaller share of the carrying capacity per citizen and the countries with a higher GDP per citizen would have a larger share. Seen isolated on the building sector this would imply that a building with the same environmental impact in i.e. Europe and Africa could be evaluated respectively sustainable and non-sustainable due to the difference in allocated capacity. This approach is though found too contradictory to the sustainability term as it favours some human beings over others, and is therefore omitted from the study. There are thus many challenges and ambiguities associated with the allocation of the carrying capacity, and the “fair share” allocated to the building may vary with perspective. The economic allocation method based on the person equivalent capacity was chosen to form the basis for the result normalization in the subsequent analysis in the study, resulting in an allocation of 11,2% of the person equivalent carrying capacity in all impact categories. This is however not tantamount to defining this method as the most fair or proper method, but based on the fact, that the economic allocation method is more widely accepted as allocation method. The economic allocation method chosen as the analysis basis is the one, out of the three methods, allocating the largest share of the carrying capacity in all impact categories, except for the climate change category. Depending on the allocation method, the carrying capacity allocated to the dwelling would therefor most likely be even smaller than the one used as the analysis basis, with an even larger transgression of the boundaries as a result.
DISCUSSION       55/74 5.2 Environmental pressure from current construction methods Besides the model used in the validation process, the LCA models are based on a wider boundary system than normally used in building LCA’s, see a detailed description in section 3.2. The system boundaries of the LCA are widened out based on the assumption, that this will increase the probability of the buildings resulting impacts, estimated through the LCA, being closer to the dwelling’s absolute impacts. In the prevalent approach to building LCA certain areas, such as the construction phase, is left out due to uncertainties and variations which complicates benchmarking of buildings. The validation process of the model build-up, where the prerequisites in form of system boundaries, materials etc. were sought identical to those of the SBI studies, showed large deviations on the output results. From the Standard house the deviation from the SBI results were +15% and for the Upcycle house it was +100%. The identified resulting impacts from the building are thus seen dependent on presumptions made along the LCA as well as the background data used. This underlines the “non-absoluteness” of the identified resulting impacts from the buildings. 5.2.1 Standard house The Single-family house is the most prevalent housing type in Denmark representing 43% (Statistic Denmark, 2015) of all housing units, and the Standard house used in the project represents prevalent Danish construction design and material choices. The resulting environmental impact from the Standard house is therefore assumed representative for a typical new built Danish single-family house built according to LEK2015. When the impact from the LCA was normalised according to the carrying capacity allocated to the building using the allocation method based on economic value, the Standard house was seen to exceed the capacity immensely within two categories; climate change and freshwater eutrophication. The climate change boundary was seen transgressed with up to a factor 15 depending on the capacity definition, and the freshwater eutrophication with a factor 4. Further more the impact from the Standard house was seen to approach the boundaries of additionally two categories; freshwater ecotoxicity and water depletion. It thus clearly shows how the Standard house impacts the environment in a way that is far from sustainable. Based on the analysis a development into an absolute sustainable state is seen to require a cutback of more than 90% on current climate change impact from the dwelling, and more than 80% cutbacks on freshwater eutrophication impacts.
  DISCUSSION   56/74   5.2.2 Upcycle house The Upcycle house represent state-of-the-art in Denmark within reducing the environmental impact from the building materials, and the analysis shows that the impact on climate change is reduced by 30% compared to the Standard house if all impacts are included. If only looking at material and construction the decrease in impact on climate change is seen to be 65% compared to the standard house. Although the impacts from material and construction are remarkably reduced from the Standard house to the Upcycle house, the impacts from the Upcycle house is still far from absolute sustainable. The impact on climate change is seen to transgress the capacity with up to a factor 10 and the freshwater with a factor 3,5. The pressure on water depletion is seen decreased from an impact corresponding to 74% of the capacity from the Standard house to 61% for the Upcycle house. For the freshwater ecotoxicity the pressure is seen reduced from an impact corresponding to 94% of the capacity to 87% of the capacity for the Upcycle house. The general picture is still clear though, when it comes to the impact on climate change and freshwater eutrophication, the Upcycle is far from absolute sustainability. 5.2.3 Sensitivity analysis From the sensitivity analysis the determination of the carrying capacity as well as the building impacts is seen to be important. The Standard house is however still seen far from absolute sustainable even if the calculated carrying capacity is assumed underestimated by 15% as well as the building impacts is assumed overestimated by 15% (scenario 3). In that case the climate change capacity is still transgressed by a factor 10 and the freshwater eutrophication with a factor 3. The sensitivity analysis thus underlines that both the standard house and the Upcycle house is far from absolute sustainability, but it also underlines the importance of estimating both carrying capacity as well as building impact as correct and close to reality as possible. 5.3 Validation of model build-up The validation process provided a foundation for a critically examination of the model build-up as well as an identification of the possible result deviations on LCA’s carried out with a wide range of identical prerequisites. The deviation of the resulting GWP impact is though seen +15% on the reference house model and +100% on the Upcycle house model, even though many of the basic prerequisites were identical to the ones used by SBI. When it comes to the remaining four impact categories, the deviations were seen to be remarkable higher than for the GWP, ranging between +75% for AP up to +388% for EP. Even though the prerequisites are strived to be alike, there are though many parameters such as database type, conversion factors etc. that have influence on the output and can vary from LCA to LCA, and with no clear right or wrong answer. From the validation process it thus clearly shows how the resulting impacts may
DISCUSSION       57/74 contain large deviations due to assumptions made in the LCA, even though the initial inventory basis is the same. This validation process thus contributes to an important insight into the absoluteness or non-absoluteness of the determination of buildings environmental impact, and how this can deviate notable from one analysis to another, even when based on the same methodological approach and the same basic inventory data. If the inventory data were also individually collected one could only imagine what this would result in deviations between models. 5.4 The absolute sustainable building As described above both the Standard house and the Upcycle house are far from absolute sustainability. The following section will thus discuss the potential of reducing the impacts and obtaining an absolute sustainable building. To reduce the impacts from the Standard house four key parameters were identified: • Use phase energy (heat and electricity), impacts per m2 • Materials and construction, impacts per m2 • Living area per person (building size) • Projection of the carrying capacity In the following the potential of each parameter is identified followed by a development of three scenarios leading to the absolute sustainable building in 2050. 5.4.1 Use phase energy From the results described in section 4.3 the use phase energy is seen to contribute significantly to the buildings environmental impacts. For the Standard house the use phase energy constitute 56% of the climate change impact when built according to LEK2015, and 40% when according to BK2020. The size of the impacts from use phase energy per square meter building is dependent on two primary parameters; the magnitude of the energy consumption as well as the energy supply mix. From section 4.3.1 the effect of a decrease in energy consumption from LEK2015 to BK2020 on the Standard house is illustrated. The exploitation of the climate change capacity is seen reduced by 25% from 1563% to 1152%. The transgressions are though still immense, and even if the energy consumption during the use phase is zero the impacts from the building’s transgression of the capacity is still significant. The same tendencies are seen for the Upcycle house. The projection of the energy supply mix is an important factor for the future impact of the buildings since the ratio of respectively fossil- and renewable fuels is of great importance when the impact per kWh is
  DISCUSSION   58/74   determined. The Danish energy policy is aiming at a fossil free energy mix in 2050, which will cause the environmental impacts per kWh to decrease. 5.4.2 Materials and construction The impacts from materials and construction is representing 44% of the climate change impact when the Standard house is built according to LEK2015, and 60% when built according to BK2020, and is thus seen as an important factor when reducing the buildings total impact. From the total impact from materials and construction the impact from construction energy represent around 12% for the Standard house but 35% for the Upcycle house. Reducing the impact from materials is thus seen as an important factor in reducing the total impact from the building, but also reducing the energy for constructing the building is relevant and the importance of the construction energy is seen to increase the more the impact from materials is reduced. For materials and construction to constitute 44% of the climate change impact is somewhat higher than identified in other similar studies (SBI, 2015; SBI, 2013), and this divergence is presumed rooted in two things; lifetime assumptions and system boundaries. This analysis is based on a building lifetime of 50years, and if an increased lifetime is assumed, naturally the impact from materials and construction is distributed over a longer period of time and thus decreasing the yearly impact. Secondly the current analysis is based on wider boundaries than commonly used in building LCA’s to obtain more absolute impacts. Some of the bigger variations in boundaries concern inclusion of the construction phase as well as additional transport processes, which both contribute to an increased weight of material and construction. Besides reducing the impact from materials through reducing the quantity of material used as well as using low-impact materials, the lifetime of the building also plays an important role. As the lifetime influence on the yearly impact from materials and construction is distributed over a longer period of time when the lifetime is increased. The building lifetime used in the LCA is 50 years, corresponding to the lifetime used by DGNB. The influence of an increased lifetime from 50 to 120years was therefore identified, see section 4.4. Additional replacements of building elements was included in the analysis, but normally when a building lifetime exceeds 40-50 years it needs profound modernizations to be contemporary and this additional use of material was not included in the analysis. When the lifetime of the Standard house was increased to 120 years, the yearly impact solemnly from materials and construction where seen to decrease by 40% on the climate change impact and by 30% on freshwater eutrophication. With the Upcycle house the decreases where seen slightly higher with 43% on climate change impact and 33% on freshwater eutrophication. Increasing the building lifetime without adding the need for additional modification, implying a contemplated design and material selection in the building design phase, is thus seen to reduce the impact from materials remarkably.
DISCUSSION       59/74 5.4.3 Living area per person An effective way to decrease the total impact from the building would be to decrease the living area per person, this both influence on the amounts of materials as well as the use phase energy. To visualize the effect of a decreased living area, the impacts relative to the carrying capacity are illustrated according to the size of the living area in Graph 2. Graph 2 Influence of living area per person on the impact relative to the carrying capacity. Based on the Upcycle house with energy consumption according to LEK2015. If built according to the Upcycle house and with energy consumption according to LEK2015 the area per person only amounts to around 5m2 if the environmental impact is to stay within the carrying capacity. Currently the living area per person is seen to be 40m2 for the Upcycle house in its original size (104 m2 ), 49 m2 for the Standard house and 53m2 for the average Danish dwelling. If the energy consumption is decreased to comply with BK2020, Graph 3 shows how the area per persons rises slightly from 5m2 to around 7 m2 if staying within the carrying capacity. 0   200   400   600   800   0   5   10   15   20   25   30   35   40   45   50   55   Impact  relative  to  carrying  capacity  [%]   Living  area  [m2/person]   Relation  between  living  area  and  relative  impact   -­‐  Upcycle  house  Br2015  -­‐   Terrestrial  acidiXication   Water  depletion   Landuse,  biodiversity   Climate  change,  temp   Climate  change,  rad.  Forc   Ozone  depletion   Freshwater  eutrophication   Marine  eutrophication   Terrestrial  eutrophication   Ozone  formation   Freshwater  ecotoxicity   Carrying  capacity   Upcycle  house   Standard  house   DK  Average   Freshwater  eutrophication  
  DISCUSSION   60/74   Graph 3 Influence of living area per person on the impact relative to the carrying capacity. Based on the Upcycle house with energy consumption according to BK2020. The correlation between the relative impact and the living area is assumed linear, and is based on the impact per square meter found in the LCA based on the house in its full size. This is though a simplification, since the impact per square meter supposedly would increase des smaller the house. Some of the building impacts are not dependent on the area but would be similar no matter the total area, i.e. hot water tank etc., but with a smaller living area the impact from these non-area dependent impacts would be distributed over fewer square meters leading to an increased impact per square meter. The societal trend though is not decreasing but increasing living areas, and from 1981 to 2014 the average living area per person in Denmark rose with 21% from 42,9m2 in 1981 to 52,1m2 in 2014, see Graph 4. The average unit size though only rose around 5% in the same period, and the increase in living area per person is therefor presumably due to a decreased number of people per unit and not solemnly due to an increased building size. 0   200   400   600   800   0   5   10   15   20   25   30   35   40   45   50   55   Impact  relative  to  carrying  capacity  [%]   Living  area  [m2/person]   Relation  between  living  area  and  relative  impact   -­‐  Upcycle  house  Br2020  -­‐   Terrestrial  acidiXication   Water  depletion   Landuse,  biodiversity   Climate  change,  temp   Climate  change,  rad.  Forc   Ozone  depletion   Freshwater  eutrophication   Marine  eutrophication   Terrestrial  eutrophication   Ozone  formation   Freshwater  ecotoxicity   Carrying  capacity   Climate  change,  temp.   Freshwater  eutrophication   Upcycle  house   Standard  house   DK  average  
DISCUSSION       61/74 Graph 4 Average living area per person in Denmark from 1981-2014 (Statistic Denmark, 2015) 5.4.4 Projection of the carrying capacity The carrying capacity is throughout the analysis stated as a person equivalent and threated as a static figure. However, this is a simplification in several aspects. Ecosystems as well as our climate are complex systems, which are interrelated in a comprehensive net of feedback-mechanisms and the carrying capacity of these systems would most likely differ over time as well as with a changing pressure. In the following the worlds total environmental carrying capacity is assumed constant, and a decline in carrying capacity ie. when the pressures over a period of time exceeds the capacity is thus not considered. A more straightforward projection of the person equivalent carrying capacity is though based on population growth. If the total carrying capacity were assumed stable, a growth in population would most naturally lead to a decline in carrying capacity per person. To identify the influence of population growth on the person equivalent carrying capacity a projection is carried out based on population prospects from UN (2013). The person equivalent is initially estimated on a population of 6,92 billion people globally in 2010 (Bjørn & Hauschild, 2015), and from population projections from the UN the population in 2050 would have increased to around 9,55 billion people and in 2100 to around 10,9 billion (UN, 2013). 0   50   100   150   0   20   40   60   1980   1985   1990   1995   2000   2005   2010   2015   Unit  size  [m2/unit]   Living  area  per     [m2/person]   Average  living  area  per  person,  DK   Living  area   Unit  size  
  DISCUSSION   62/74   Graph 5 Projection of the decline in person equvivalent carrying capacity allocated to the building due to population growth. Here illustrated on the global warmning potential. Population project according to UN (2013) From Graph 5 it shows how the carrying capacity per person will decline due to an increased global population. From 2010-2050 the carrying capacity per person will decline by 28% alone due to population growth and again from 2050-2100 a decline of additionally 12% is seen. This corresponds to a total decline in carrying capacity from 2010 to 2100 of 37% due to global population growth alone. 5.4.5 Scenarios 2050: The absolute sustainable building The Standard house represents the prevalent single-family housing type today, and the development of three scenarios for the absolute sustainable building in 2050 therefore takes its basis in the Standard house. To obtain the needed changes for the Standard house to become absolute sustainable four key parameters have been identified; use phase energy, materials and construction, living area per person and the projection of the carrying capacity. First the potential of each of the four parameters is assessed and then followed by the three scenarios identifying a range of parameter changes leading to absolute sustainability in 2050. The projection of the carrying capacity is maintained as illustrated in Graph 5 for all scenarios and only the three remaining parameters are modified. 5.4.5.1 Scenario 1 Scenario 1 is based on a modification of all three free parameters. From Figure 25 it shows how a reduction of 93% on respectively the impact per square meter from both use phase energy and materials are required together with a reduction of the living area on 39% if the building is to be absolute sustainable in 2050. The reduction of 93% on use phase energy corresponds to a climate change impact of 0,78 kgCO2eq/m2 in 2050. The climate change impact in 2015 is 10,4kgCO2/m2 , and if built according to BK2020 and with the current energy supply mix the climate change impact would be 5,5kgCO2eq/m2 . If the Standard house were built according to BK2020 the absolute sustainability would thus still require an additional 86% reduction. 0,00   5,00   10,00   15,00   0   50   100   150   2010   2020   2030   2040   2050   2060   2070   2080   2090   2100   Population    [billions]   Capacity    [kgCo2/person/yr]   Carrying  capacity,  GWP   Allocated  to  the  building,  based  on  exonomic  allocaion   Capacity,  GWP   Population  
DISCUSSION       63/74 When it comes to the impact from material and construction the 93% reduction corresponds to an impact of 0,62kgCO2eq/m2 in 2050. If put into perspective, the impact from the Upcycle house is 2,82kgCO2eq/m2 , and the reduction required from the Standard house is thus an additional 78% from the Upcycle house impact. If the lifetime of the Upcycle house were prolonged to 120years the climate change impact would decrease to 1,7kgCO2eq/m2 , which is still almost a factor 3 more than the required 0,62kgCO2eq/m2 . When it comes to the living area, the reduction of 39% corresponds to a living area per person of 30m2 in 2050, and with an average of 2,6 person per building this corresponds to a single-family house of 78m2 . Scenario 1: The absolute sustainable building 2050 Use phase energy [kgCO2eq/m2 /yr] Material and construction [kgCO2eq/m2 /yr] Living area per person [m2 ] Carrying capacity [kgCO2eq/building/yr] Use phase energy [kgCO2eq/m2 /yr] Material and const. [kgCO2eq/m2 /yr] Living area [m2 /person] Carrying capacity [kgCO2eq/build/yr] 2015 10,4 8,2 49 152 2050 0,78 0,62 30 109 2050/2015 ratio 0,075 0,075 0,612 0,717 Figure 25 Requiered changes for the Standard house to reach absolute sustainability in 2050, Scenario 1 The reductions needed in order to reach absolute sustainability in 2050 are immense. Even if the living area is reduced by 40% the impact from use phase energy per square meter needs to reach a level corresponding to an 86% reduction compared to BK2020 and the impact from materials per square meter needs to reach a level corresponding to an 78% reduction of the impact from Upcycle house. 0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   20   40   60   2015   2020   2025   2030   2035   2040   2045   2050   0   100   200   2015   2020   2025   2030   2035   2040   2045   2050  
  DISCUSSION   64/74   5.4.5.2 Scenario 2 In scenario 2 the living area person is kept constant at an area of 49m2 , equal to the current living area per person of the Standard house, and only the impact from use phase energy and material and construction are altered. From Figure 26 the required changes for the scenario is illustrated, and it shows how the reduction of the impacts from use phase energy and material and construction is required to be 96% when the living area is kept constant. Scenario 2: The absolute sustainable building 2050 Use phase energy [kgCO2eq/m2 /yr] Material and construction [kgCO2eq/m2 /yr] Living area per person [m2 ] Carrying capacity [kgCO2eq/building/yr] Use phase energy [kgCO2eq/m2 /yr] Material and const. [kgCO2eq/m2 /yr] Living area [m2 /person] Carrying capacity [kgCO2eq/build/yr] 2015 10,4 8,2 49 152 2050 0,47 0,37 49 109 2050/2015 ratio 0,045 0,045 1 0,717 Figure 26 Requiered changes for the Standard house to reach absolute sustainability in 2050, Scenario 2 5.4.5.3 Scenario 3 In scenario 3 the impact from materials and construction is kept constant, indicating a continuous use of current building materials and the remaining two parameters, impact from use phase energy and living area are altered, see Figure 27. Continuous use of current building materials and construction methods thus require a 90% reduction on the impact from use phase energy per square meter as well as a 90% reduction of the actual living area. 0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   20   40   60   2015   2020   2025   2030   2035   2040   2045   2050   0   100   200   2015   2020   2025   2030   2035   2040   2045   2050  
DISCUSSION       65/74 Scenario 3: The absolute sustainable building 2050 Use phase energy [kgCO2eq/m2 /yr] Material and construction [kgCO2eq/m2 /yr] Living area per person [m2 ] Carrying capacity [kgCO2eq/building/yr] Use phase energy [kgCO2eq/m2 /yr] Material and const. [kgCO2eq/m2 /yr] Living area [m2 /person] Carrying capacity [kgCO2eq/build/yr] 2015 10,4 8,2 49 152 2050 1,04 8,2 4,9 109 2050/2015 ratio 0,1 1 0,1 0,717 Figure 27 Requiered changes for the Standard house to reach absolute sustainability in 2050, Scenario 3 5.5 Uncertainties and future work As identified in the literature study there is virtually no preceding work on coupling building environmental impacts to carrying capacity. The work in this master’s thesis is thus only in the preliminary stages of identifying an absolute sustainability assessment for buildings, and refinement of the method in many aspects is required. 5.5.1 Carrying capacity For the identification of the carrying capacity allocated to the dwelling there is two main uncertainties; the capacity estimations and the following allocation of a share to the dwelling. 0,0   5,0   10,0   15,0   2015   2020   2025   2030   2035   2040   2045   2050   0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   20   40   60   2015   2020   2025   2030   2035   2040   2045   2050   0   100   200   2015   2020   2025   2030   2035   2040   2045   2050  
  DISCUSSION   66/74   According to Bjørn & Hauschild (2015) there are several important uncertainties related to the estimation of carrying capacity. For instance the estimates are based on models simplifying reality, but also the definition of carrying capacity involves ambiguities and is by Bjørn & Hauschild (2015) based on scientific consensus. In this study the carrying capacity was only allocated to dwellings, but an allocation to the remaining building types such as offices and schools is also relevant to carry out. Allocation to the remaining building types will though most likely be more complicated than to the dwelling, since the inventories on for instance the economic values they represent might not be as clear and distinctly identified as for the dwellings, since the dwellings could be identified via the household budget. The allocation was carried out using respectively one method based on economic value and two based on current environmental pressure. As mentioned earlier there are pros and cons in both the economic and the environmental allocation approach, and additional work on a possible merging of the two methods so both economic value and environmental pressure were accounted for could be interesting. The work on allocating the carrying capacity is though more a political issue than an engineering issue, and the future work ought to involve social scientist for instance. 5.5.2 Quantification of absolute impacts An LCA is initially indented for a relative performance indication. Evaluating the absolute sustainability though implies that the identified impacts from the building reflect the absolute (or total) impacts. Identifying the absolute impacts through an LCA therefore needs a refinement of the methodology. The characterisation method for the impact characterisation also includes uncertainties and would require additional work, in the study the characterisation of land erosion especially stood out. For the impact estimations made in this study to approach the absolute impacts even more, the estimation of the energy consumption of the building would need additional work. The energy consumption used in the study was related to the Danish energy frame, and the actual energy consumption is known to differ from this. Besides the fact that only the building regulated energy consumption was included, leaving out electricity for appliances, lighting etc., energy consumption is also seen to vary from residents to residents. Apart from the energy consumption there are ambiguities in defining what impacts should be included in the absolute impacts from the building. A building has a lot of derived effects, and for instance a specific building design could promote an energy saving behaviour, as well as a building close to public transportation could reduce the residents impacts from transportation. Further more the quantification of environmental impacts were only carried out for a single-family house, but identifying it for the remaining housing types such as apartments and townhouses would also be interesting. Also the impact of the remaining building types such as offices and schools are interesting. Further more a study of the impacts from the existing building mass could be an important step, since a great deal of the environmental impacts from buildings is bound within the existing building mass.
DISCUSSION       67/74 When developing scenarios that are reaching absolute sustainable buildings in the future the energy supply mix is an important factor when determining the impacts from the use phase energy. A projection of the energy mix is not included in this study, and including this is an important step in the future works on the scenario development. Additionally a study of the influence of energy producing facilities such as solar- or earth heat related to the building would be interesting.
  DISCUSSION   68/74  
CONCLUSION  AND  RECOMENDATIONS       69/74 6 CONCLUSION AND RECOMENDATIONS The developed normalisation method allows for an absolute sustainability assessment of a building, where the building impacts are compared to the share of environmental carrying capacity that by a fair distribution are allocated to the building. As a basis for the normalisation, different allocation scenarios were carried out to identify the “fair share” of the environmental carrying capacity that should be allocated to the building. An allocation of 11,2% of the person equivalent carrying capacity in all impact categories were used as a basis for the further analysis, but the allocation process provided an important insight into the complexity of the allocation, and the share used as analysis basis should not be considered definite. An absolute sustainability assessment were carried out on two reference buildings, a standard house representing the prevalent Danish single-family house in both size and construction type and a building representing state-of-the-art when comes to reducing environmental impacts from materials. The assessment showed that both buildings were far from absolute sustainability. The carrying capacities were immensely transgressed on climate change and freshwater eutrophication for both buildings. Further more the impact on both water depletion and freshwater ecotoxicity were approaching the limits for both the Standard house and the Upcycle house. Due to a rising population the carrying capacity was found to decline by 28% from 2010 to 2050. This decline was combined with a projection of three scenarios leading to absolute sustainable buildings in 2050. The common denominator for the three scenarios were the immense reductions needed, and for instance if the living area were reduced by 40% by 2050, the impacts from use phase energy should be reduced with 93% and the same reduction would be needed for the impacts from materials and construction to reach absolute sustainability.
  CONCLUSION  AND  RECOMENDATIONS   70/74  
REFERENCES       71/74 7 REFERENCES Aysin, S., 2011. A comparative analysis of building environmental assessment tools and suggestions for regional adaptations. Civil Engineering and Environmental Systems, September. pp.231-45. Bendewald, M. & Zhai, Z.., 2013. Using carrying capacity as a baseline for building sustainability assessment. Habitat International, pp.22-32. Beradi, U., 2012. Sustainability Assessment in the Construction Sector: Rating Systems and Rated Buildings. Sustainable Development, pp.411-24. Birkved, M. & Goldstein, B., n.d. Environmental sustainability assessment of urban systems applying coupled urban metabolism and life cycle assessment. In Höfler, K., Maydl, P. & Passer, A., eds. Proceedings of the sustainable buildings - Construction products and Technologies: Collection of full papers. Graz Verlag der Technischen Universität Graz. Bjørn, A., Diamond, M.L., Birkved, M. & Hauschild, M.Z., 2014. A chemical footprint method for improved communication of freshwater ecotoxicity impacts in the context of ecological limits. Environmental Science & Technology, 27. October. Bjørn, A. & Hauschild, M.Z., 2015. Introducing carrying capacity based normalisation in LCA: framework and development of midtpoint level references. The International Journal of Life Cycle Assessment. The article is currently in for review, 21.january 2015. BREEAM, 2015. Building Research Establishment Environmental Assessment Method. [Online] Available at: www.breeam.org [Accessed 27 January 2015]. For amount of certified building see: http://www.breeam.org/about.jsp?id=66. CASBEE, 2015. Comprehensive Assessment System for Built Environment Efficiency. [Online] Available at: www.ibec.or.jp [Accessed 27 Janyary 2015]. For method see: http://www.ibec.or.jp/CASBEE/english/methodE.htm. Cuéllar-Franca, M.R. & Azapagic, A., 2012. Environmental impacts of the UK residential sector: Life cycle assessment of houses. Building and Environment, pp.86-99. DGNB, 2015. Deutche Gesellschaft für Nachhaltiges Bauen. [Online] Available at: www.dgnb-system.de [Accessed 23 January 2015]. For number of consultants and auditors see: http://www.dgnb-
  REFERENCES   72/74   system.de/en/certification/dgnb-auditors-consultants/ For number of certified buildings see: http://www.dgnb-system.de/en/projects/. DiMento, J.F.C. & Doughman, P., 2007. Climate change: What it means for us, our children and our grandcihldren. Cambridge: MIT Press. DK-GBC, 2014. DGNB system Denmark manual for kontorbygninger 2014 1.1. Denmark: DK-GBC Green building council Denmark. DK-GBC, 2015. Green Building Council Denmark. [Online] Available at: www.dk-gbc.dk [Accessed 23 January 2015]. Ecoinvent, 2007. Overview and methodology - Data v2.0 (2007). Ecoinvent report no.1. Dübendorf: Swiss centre for life cycle inventories. EEA, 2013. No 2/2013 Environmental pressures from European consumptrion and production. Technical report. Copenhagen: European Environmental Agency European Environment Agency. ISSN 1725-2237, doi:10.2800/70634. EPD Danamark, 2015. EPD Danmark. [Online] Available at: www.epddanmark.dk [Accessed 11 Feburary 2015]. European Commission, 2006. Environmental Impact of Products (EIPRO) - Analysis of the life cycle environmental impacts related to the final consumption of the EU-25. Technical Report EUR 22284 EN. Spain: European Comission. Eurostat, 2015. European comission. [Online] Available at: http://ec.europa.eu/eurostat [Accessed March 2015]. FOEN, 2011. Environmental Impacts of Swiss Consumption and Production - A combination of input-output anlysis with life cycle assessment. Bern: FOEN Foderal Department of Environment, Transport, Energy and Communication (DETEC). Giama, E. & Papadopoulos, A.M., 2012. Sustainable building management: Overview of certification schemes and standards. Advances in Building Energy Research, October. pp.242-58. Global Footprint Network, 2010. Ecological Footprint Atlas. Oakland: Global Footprint Network. Haapio, A. & Viitaniemi, P., 2008. A critical review of building environmental assessment tools. Environmental Impact Assessment Review, pp.469-82. iiSBE, 2015. International Initiative for a Sustainable Built Environment. [Online] Available at: www.iisbe.org [Accessed 27 January 2015]. For scope and method see: http://iisbe.org/sbmethod.
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Appendices - The absolute sustainable building – TABLE OF CONTENT APPENDIX  A:  INVENTORY  LIST  UPCYCLE  HOUSE  ...........................................................................................  1   APPENDIX  B:  INVENTORY  LIST  STANDARD  HOUSE  .......................................................................................  4   APPENDIX  C:  END  OF  LIFE  FLOWS  .......................................................................................................................  6   APPENDIX  D:  MATERIAL  PROPERTIES  ..............................................................................................................  8   APPENDIX  F:  ENVIRONMENTAL  IMPACTS  ........................................................................................................  9   APPENDIX  G:  PROLONGED  LIFETIME  ...............................................................................................................  10   STANDARD  HOUSE  (EXCLUDING  USE  PHASE  ENERGY)  ...........................................................................................................  10   UPCYCLE  HOUSE  ............................................................................................................................................................................  11   APPENDIX  H:  SENSITIVITY  -­‐  SUB  CATEGORIES  .............................................................................................  12   APPENDIX  I:  MODEL  VALIDATION  .....................................................................................................................  13   1.1.1   Alternation  of  models  ..............................................................................................................................................  13   1.1.2   Sources  of  errors  ........................................................................................................................................................  14   APPENDIX  J:  SUB-­‐CAT.  EXPENSES  CP04-­‐05  ....................................................................................................  16   APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)  .............................................................................  18  
Master's thesis: The absolute sustainable building
APPENDIX  A:  INVENTORY  LIST  UPCYCLE   HOUSE       1/22 APPENDIX A: INVENTORY LIST UPCYCLE HOUSE Mass [kg/m2] Service life [yr] Upcycle factor Ecoinvent dataset EoL flow Foundations Screwfoundation 14 120 0,12 RER: Steel, low alloyed, at plant 3 Concrete (plates) 28 120 0,12 CH: Concrete, normal, at plant 1 Gravel 249 120 CH: Gravel, crushed, at mine 4 Ground slab0,12 Container 16 120 RER: Steel, low-alloyed, at plant 3 Plast foil 0,4 120 RER: Polyethylene, LDPE, granulate, at plant 5 EPS 4,7 120 0,35 RER: Polystyren foam slab, at plant 2 Wood laths 2,2 120 0,12 RER: Sawn timber, softwood, planned, air, at plant 8 Paperwool insulation 10 120 See datasets in table below 14 Outer walls Richlite composite 8,3 60 0,37 x RER: phenolic resin, at plant + 0,63 x RER: waste paper, sorted, for further treatment 18 Paperwool insulation 22 60 See datasets in table below 14 Plaster (wind) 14 60 0,35 CH: gypsum plaster board, at plant 7 Container 22 120 0,12 RER: steel, low-alloyed, at plant 3 Plast foil 0,3 60 RER:polyethylene, LDPE, granulate, at plant 5 Trapezodial sheets (alu) 0,7 40 0,67 RER: aluminium alloy, AlMg3, at plant 11 Plaster board 29 40 0,35 CH: gypsum plaster board, at plant 7 Structural timber 0,5 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Inner walls Container 22 120 0,12 RER_ steel, low-alloyed, at plant 3 OSB-plates 24 25 RER: oriented strand board, at plant 8 Paperwool insulation 4,0 60 See datasets in table below 14 Structural timber 1,6 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Poli brick 0,9 60 0,5 RER: polyethylene terephthalate, granulate, bottle grade, at plant 15 Roof Plaster board 8,7 40 0,35 CH: gypsum plaster board, at plant 7
  APPENDIX  A:  INVENTORY  LIST  UPCYCLE  HOUSE   2/22   Structural timber 15 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Container 1,9 120 0,12 RER_ steel, low-alloyed, at plant 3 Paperwool insulation 23 40 See datasets in table below 14 Trapezodial sheets (alu) 3,2 40 0,67 RER: aluminium alloy, AlMg3, at plant 11 Doors and windows Windows (3-layer, thermo) 18 25 0,12 RER: glazing, triple (3-IV), U<0,5W/m2K, at plant 10 Window frame 0,6 50 0,67 RER: window frame, aluminium, U=1,6W/m2K, at plant 11 Silicone sealants 0,1 50 RER: polysulphide, sealing compound, at plant 16 Wooden door 4,5 60 0,35 RER: door, inner, wood, at plant 8 Floors and surfaces Structural timber 7,4 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 OSB-plates 14 40 0,6 RER: oriented strand board, at plant 8 Tiles, non-glazed 2,2 60 CH: ceramic tiles, at regional storage 4 Paint, water based 0,1 10 0,5 RER: alkyd paint, white, 60% in H2O, at plant 12 Installations Water pipes 0,1 60 RER: steel, low-alloyed, at plant 3 Sanitary ceramics 0,3 40 CH: sanitary ceramics, at regional storage 4 Hot water tank 0,4 30 CH: hot water tank 600l, at plant 3 Heaters 1,8 30 0,3 RER:steel, low-alloyed, at plant 3 Circulation pump 0,05 20 CH: pump, 40W, at plant 3 Ventilation unit 1,3 25 CH: ventilation system, decentralized, 6x120m3/h, steel ducts, without GHE 3 Terrace and greenhouse UPM composite 9,4 60 0,35 0,31*RER: polyethylene, LDPE, granulate, at plant + 0,69* CH: cellulose fibre, inclusive blowing in, at plant 14 Brick wall (old bricks) 41 120 0,5 RER: brick, at plant 4 Mortar (wall) 8,5 120 CH: cement mortar, at plant 6 Brick floor (old bricks) 45 120 0,5 RER: brick, at plant 4 Mortar (floor) 9,4 120 CH: cement mortar, at plant 6 Window panes 2,5 80 0,12 RER: flat glass, uncoated, at plant 17
APPENDIX  A:  INVENTORY  LIST  UPCYCLE   HOUSE       3/22 Glassshaum granulate (insulation) 10 120 RER: foam glass, at plant 4 Paperwool Share of mass Dataset 0,02 RER: tap water, at user 0,05 RER: boric acid, anhydrous, powder, at plant 0,01 RER: borax, anhydrous, powder, at plant 0,07 RER: aluminium hydroxide, at plant 0,85 RER: waste paper, sorted, for further treatment
  APPENDIX  B:  INVENTORY  LIST  STANDARD  HOUSE   4/22   APPENDIX B: INVENTORY LIST STANDARD HOUSE Mass [kg/m2] Service life [yr] Ecoinvent dataset EoL flow Foundations Concrete 227 120 CH: concrete, normal, at plant 1 Light weight concrete 25 120 CH: lightweight concrete block, expanded perlite, at plant 1 EPS 1,5 120 RER: polystyren foam, at plant 2 Ground slab Concrete 232 120 CH: concrete, normal, at plant 1 Reinforcement steel 14 120 RER: reinforcing steel, at plant 3 EPS 5,5 120 RER: polystyren foam, at plant 2 Gravel 320 120 CH: gravel, crushed, at mine 4 Plast foil 0,1 120 RER: polyethylene, LDPE, granulate, at plant 5 Outer walls Aerated concrete 41 120 CH: autoclaved aerated concrete block, at plant 1 Mineral wool 10 120 CH: glass wool mat, at plant 4 Brick 137 120 RER: brick, at plant 4 Mortar 29 120 CH: cement mortar, at plant 6 Inner walls Aerated concrete 35 100 CH: autoclaved aerated concrete block, at plant 1 Plaster (filler) 3,4 40 CH: gypsum plaster board, at plant 7 Glass fibre fabric 0,1 120 RER: glass fibre, at plant 4 Roof Structural timber 10 120 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Bitumen membrane 7,6 60 RER: bitumen sealing, V60, at plant 9 Plast foil 0,2 60 RER: polyethylene, LDPE, granulate, at plant 5 Mineral wool 14 120 CH: glass wool mat, at plant 4 OSB plates 14 60 RER: oriented strand board, at plant 8 Tiles 69 60 RER: roof tile, at plant 4 Plaster 6,5 40 CH: gypsum plaster board, at plant 7 Doors and windows Glazing, thermo (3- layer) 5,5 25 RER: glazing, triple (3-IV), U<0.5W/m2K, at plant 10 Window frame, alu 0,9 50 RER: window frame, aluminium, U=1.6W/m2K, at plant 11 Window sill, wood 1,4 50 RER: window frame, wood, U=1.5W/m2K, at 8
APPENDIX  B:  INVENTORY  LIST   STANDARD  HOUSE       5/22 plant Wooden doors 3,7 60 RER: door, inner, wood, at plant 8 Floors and surfaces Paint, waterbased 0,3 10 RER: alkyd paint, white, 60% in H2O, at plant 12 Rug 0,7 30 GLO: textile, woven cotten, at plant 13 Tiles, glazed 0,8 60 CH: ceramic tils, at regional storage 4 Wodden floors 1,3 60 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Tile adhesive 2,2 30 CH: adhesive mortar, at plant 18 Tiles, non-glazed 5,0 60 CH: ceramic tiles, at regional storage 4 Installations Sanitary ceramics 0,5 40 CH: sanitary ceramics, at regional storage 4 Hot water tank 0,3 30 CH: hot water tank 600l, at plant 3 Circulation pump 0,04 20 CH: pump 40W, at plant 3 Ventilation unit 0,8 25 CH: ventilation system, decentralized, 6 x 120 m3/h, steel ducts, without GHE 3 Water pipes 0,1 60 RER: steel, low-alloyed, at plant 3 Heaters 1,8 30 RER: steel, low-alloyed, at plant 3
  APPENDIX  C:  END  OF  LIFE  FLOWS   6/22   APPENDIX C: END OF LIFE FLOWS EoL flow EoL dataset(s) Next product system – Avoided processShare of mass Dataset 1 100% CH: Disposal, concrete, 5% water, to inert material landfill 2 100% CH: disposal, expanded polystyrene, 5% water, to municipal incineration CH: heat, biowaste, at waste incineration plant, allocation price 3 CH: disposal, building, reinforcement steel, to recycling RER: steel, low-alloyed, at plant CH: disposal, steel, 0% water, to inert material landfill 4 100% Disposal inert material, 0% water, to inert material landfill 5 100% CH: disposal polyethylene, 0,4% water, to municipal incineration CH: heat, biowaste, at waste incineration plant, allocation price 6 100% CH: disposal, cement, hydrated, 0% water, to residual material landfill 7 CH: disposal, building, plaster-cardboard sandwich, to sorting plant CH: disposal, building, plaster-cardboard, sandwich, to recycling CH: Base plaster, at plant CH: disposal, inert material, 5% water, to inert material landfill 8 100% CH: disposal, wood untreated, 20% water, to municipal incineration CH: heat, biowaste, at waste incineration plant, allocation price 9 100% CH: disposal, building, bitumen sheet, to final disposal 10 CH: disposal, building, glazing, 3-IV, U<0,5W/m2K, to final disposal RER: flat glass, uncoated, at plant 11 CH: disposal, building, reinforcement steel, to recycling RER: aluminium alloy, AlMg3, at plant CH: disposal, aluminium 0% water, to sanitary landfill 12 100% CH: disposal, building, paint on wood, to final disposal 13 CH: disposal, textiles, soiled, 25% water, to CH: heat, biowaste, at waste
APPENDIX  C:  END  OF  LIFE  FLOWS       7/22 municipal incineration incineration plant, allocation price 14 CH: heat, biowaste, at waste incineration plant, allocation price 15 RER: polyetyhylene terephthalate, granulate, bottle grade, at plant 16 CH: disposal, PE sealing sheet, 4% water, to municipal incineration 17 CH: disposal, building, glass sheet, to final disposal RER: flat glass, uncoated, at plant 18 No EoL flow
  APPENDIX  D:  MATERIAL  PROPERTIES   8/22   APPENDIX D: MATERIAL PROPERTIES Recycling rates (Denmark) Material Recycling rate Reference Plastic (foil) 34,7% www.epro-plasticsrecycling.org Plaster 80% www.ecoinnovation.dk Steel 97,5% www.recycle-steel.org Aluminium 90% www.alueurope.eu Building glazing 10% Most building glazing is landfilled according to: www.glassforeurope.com . Here 90% is assumed as “most”. Material properties, Density Material Density [kg/m3 ] Concrete, normal 2200 Concrete, aerated 1000 Structural timber 450 OSB plates 680 Rug 42 Richlite composite 1213
APPENDIX  F:  ENVIRONMENTAL   IMPACTS       9/22 APPENDIX F: ENVIRONMENTAL IMPACTS Climate change Ozone depletion The greenhouse gasses are allows the short waved radiation from the sun to enter the atmosphere but keeps the long waved radiation from the earth from leaving. In that way they create a green house effect by trapping the heat in the atmosphere. The GWP varies with the greenhouse gasses, and it is therefore expressed relative to the GWP of carbon dioxide in CO2 equivalent but also within a specific time horizon since the lifetime of the gases in the atmosphere also differs. The ozone layer plays an important role for life on earth shielding it from UV-A and UV-B radiations, and thereby preventing an overheating of the earth’s surfaces as well as protects flora and fauna. A number of free radical catalysts such as nitric oxide, chlorine and atomic bromine causes a depletion of the ozone layer with consequences such as increase in tumour formations in human and animals as wells as disturbances in the photosynthesis. Human activities increase the concentrations of these free radicals by releasing man-made compounds such as CFC’s and bromofluorocarbons. Eutrophication Terrestrial acidification Eutrophication can be aquatic or terrestrial and refers to an enrichment of nutrients in a specific area. Aquatic eutrophication can cause accelerated algae growth, which over time can lead to fish dying as well as anaerobic decomposition, having severe negative impact on eco-systems. A contribution to eutrophication comes from agricultural fertilizers, air pollutants as well as wastewater. When air pollutants such as sulfur and nitrogen compounds reacts with water, sulfuric and nitric acids are created, and when the acid reaches ground level it causes damaging effects to flora and fauna. Acidic soil for instance dissolves nutrients faster causing an increased leaching of nutrients. Acidification is regarded as a regional effect, and can also have degrading effect on buildings. Photochemical ozone formation When ozone is created near ground level of the earth it is often referred to as summer-smog. It can cause negative health effects especially related to the respiratory system but can also have a negative impact on flora and fauna. Human activities affect the creation of ground level ozone mainly through incomplete combustions of fossil fuels.
  APPENDIX  G:  PROLONGED  LIFETIME   10/22   APPENDIX G: PROLONGED LIFETIME Standard house (excluding use phase energy) Annual impacts, Standard house – 128m2 , building lifetime (varies), excl. use phase energy 50yr 120yr Terrestrial acidification (AP) 83 56 mole H+ eq. Water depletion 23 13 m3 Land Use Erosion - - ton eroded soil Biodiversity 357 220 m2 *year Climate change (GWP) 1048 595 kg CO2 eq. Ozone depletion (ODP) 0,0001 0,0001 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,2 0,1 kg P eq. Marine 0,2 0,1 kg N eq. Terrestrial 41 26 mole N eq. Photochemical oxidant formation (POCP) 3 2 kg NMVOC Freshwater ecotoxicity 1206 741 PAF*m3 *day IN,B 50yr 120yr Terrestrial acidifiation 12% 8% Water depletion 26% 15% Land use Erosion - - Biodiv. 8% 5% Climate change Temp. 365% 207% Rad. for. 690% 391% Ozone depletion 0,4% 0,2% Eutrophi- cation Freshwat. 163% 109% Marine 2% 2% Terrest. 5% 3% Ozone formation 24% 14% Freshwater ecotoxicity 41% 25% Comments: Only impact from materials and construction is included. 128m2 heated area. Br2015 50 year lifetime 120 year lifetime
APPENDIX  G:  PROLONGED  LIFETIME       11/22 Upcycle house Annual impacts, Upcycle house – 128m2 , building lifetime (varies), excl. use phase energy 50yr 120yr Terrestrial acidification (AP) 59 48 mole H+ eq. Water depletion 11 7 m3 Land Use Erosion - - ton eroded soil Biodiversity 216 172 m2 *year Climate change (GWP) 361 218 kg CO2 eq. Ozone depletion (ODP) 0,0000 3 0,0000 2 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,12 0,09 kg P eq. Marine 0,11 0,08 kg N eq. Terrestrial 25 21 mole N eq. Photochemical oxidant formation (POCP) 3 59 4 8 kg NMVOC Freshwater ecotoxicity 11 7 PAF*m3 *day I/C 50yr 120yr Terrestrial acidifiation 9% 7% Water depletion 13% 8% Land use Erosion - - Biodiv. 5% 4% Climate change Temp. 126% 76% Rad. for. 237% 143% Ozone depletion 0,1% 0,1% Eutrophi- cation Freshwat. 93% 67% Marine 1,2% 0,9% Terrest. 3% 3% Ozone formation 14% 10% Freshwater ecotoxicity 35% 24% Comments: Onlys impact from materials and construction is included. 128m2 heated area. Br2015 50 year lifetime 120 year lifetime
  APPENDIX  H:  SENSITIVITY  -­‐  SUB  CATEGORIES   12/22   APPENDIX H: SENSITIVITY - SUB CATEGORIES In the allocation scenarios a range of assumptions are made when allocating the subcategories to the dwelling, i.e 30% of household electricity is used for operation of the dwelling when allocating according to economic value. Therefor a sensitivity analysis of influence of these assumptions on the final result was carried out. Many subcategories were assumed 100% allocated to the dwelling, i.e 100% of rentals is allocated to the dwelling, and these are not included in the sensitivity analysis, only assumptions where less than 100% of a subcategory is allocated are. In allocation scenario C, the EIPRO study, all relevant subcategories are allocated 100% to the dwelling, due to the background studies initial allocation work as earlier described. The final results showed only little sensitivity towards the assumptions made in the allocation of subcategories. For the global warming potential this meant a deviation of +/- 1% on the final result when deviating the allocation of subcategories with +/- 20%. Allocation scenario -20% in sub.cat - +20% in sub.cat Economic value A. Eurostat 110 111 112 Environmental pressure B. EEA 112 113 115 C. EC - 43 -
APPENDIX  I:  MODEL  VALIDATION       13/22 APPENDIX I: MODEL VALIDATION 1.1.1 Alternation of models To validate the models, a number of lifecycle stages need to be excluded, since they are not included in the method used by SBI. SBI divides the buildings life cycle into three main stages, production phase, use phase and end of life. From Table 1 similarities and differences between the analysis carried out by SBI and the current build-up in Gabi can be seen. In order to compare the results and validate the model, the processes involving construction phase (energy, spill and transport from gate to site), land use and conversion, repair in use phase, demolition of the building and transport from site to disposal has to be excluded from the model. Table 1 Processes involved in the building lifecycle in respectively the SBI analysis and the current project Production phase Use phase End of life SBI Own Model SBI Own Model SBI Own Model Extraction X X Maintenance Demolition (X) Transport X X Repair (X) Transport X Production X X Replacement X X Waste handling X X Construction X Modifications Recycling X X Landconversion X Energy X X Landfill X X Water Land use X A few exceptions are made regarding repair and demolition, which is not fully excluded from the models. In the model the materials used for repair are assumed to 1% of the initial mass of individual selected exposed materials (such as mortar, brick and rooftiles). The impacts from repair will therefore be insignificant, and
  APPENDIX  I:  MODEL  VALIDATION   14/22   since the repair part is not parameterized in the model it will not be excluded in the validation process. When it comes to demolition this is included in the EoL processes in the Ecoinvent database that directly refers to the building, ie. “Disposal, building, reinforcing steel”. In all other processes where a dataset refereeing directly to the building have not been available, the demolition is not added separately. The impacts from demolition are therefor not possible to exclude from the model, but are in line with the impact from repair expected to have negligible influence on the end results. When it comes to the end of life flows for the different materials differences are also seen between the SBI method and the current model. As opposed to the current model the SBI assessment does not include recycling potential of plaster and reinforcement steel, so recycling rates are set to 0% in these flows causing 100% of the EoL flow to landfill. Further more there are some materials where the SBI assessment does not include an EoL flow, and the EoL flow in the model is therefore set to 0. This concerns materials as the bitumen membrane in the roof of the Reference house, all glazing used as well as paint. The GaBi model of the Reference house is adjusted to include only the processes included in the SBI analysis as described in 1.1.1. For the project model this includes, inter alia, deactivation of surtain EoL flows such as the bitumen membrane in the roof as well as building glazing. Further more the building lifetime is adjusted to 120 years instead of the initial 50 years, since the SBI report involving the reference house states the resulting global warming impact based on a 120-year period. 1.1.2 Sources of errors The inventory lists are obtained from SBI, and the inventory basis is therefore identical when comes to mass and material types, but although the indata for the models are based on the same amount and material types as the SBI models, there still remain a number of assumptions, which can all lead to variations in the resulting impacts. Some of the datasets used demands conversion from mass to area or quantity, and densities used for this are based on general assumptions. Further more assumptions on recycling rates are made aiming at a recycling rate representative for the specific material in the Danish construction sector when possible. When it comes to the Upcycle house, the upcycle factors applied are in accordance with the inventory lists of SBI. Though with exception of the upcycle factor of old bricks, which do not appear in the report, but is assumed to be 0,5. The primary data source for the current project is the Ecoinvent database 2.2 where the SBI assessment is primarily based on the ESUCO database. Due to differences between the databases, this will lead to natural
APPENDIX  I:  MODEL  VALIDATION       15/22 deviations in the output results. Furthermore there are differences in the specific processes in the databases, why assumptions have been made regarding which Ecoinvent processes comes closest to the ESUCO process used in the SBI model. EPD’s have also been used as data source for some materials. In the current model the EPD’s have only been used to identify the material composition and not the resulting impacts. This can off course also lead to deviations, but was assumed to create the most accurate output result since the evaluation method of the EPD’s varies.
  APPENDIX  J:  SUB-­‐CAT.  EXPENSES  CP04-­‐05   16/22   APPENDIX J: SUB-CAT. EXPENSES CP04-05 Distribution of expenses in the sub-categories of CP04-05. Green marks categories allocated to the dwelling. Share  of  Category  [%] %  allocated  to   dwelling CP04 CP041  -­‐  Actual  rentals  for  housing CP0411  -­‐  Actual  rentals  paid  by  tenants 19,3 1,0 CP0412  -­‐  Other  actual  rentals 0,5 CP042  -­‐  Impited  rentals  for  housing CP0421  -­‐  Impted  rentals  of  owner-­‐ occupiers 51,1 1,0 CP0422  -­‐  Other  imputed  rentals 2,5 CP043  -­‐  Maintenance  and  epair  of  the   dwelling CP0431  -­‐  Materials  for  the  maintainance 3,1 CP0432  -­‐  Services  for  the  maintenance   3,2 CP044  -­‐  Water  supply  and  miscellaneous CP0441  Water  supplu 2,4 CP0442  -­‐  Refuse  collection 1,4 CP0443  -­‐  Sewerage  collection 0,1 CP0444  ther  services  relating  to  the   dwelling 1,7 CP045  -­‐  Electricity,  gas  and  other  fuels CP0451  -­‐  Electricity 7,1 0,3 CP0452  -­‐  Gas 3,9 1,0 CP0453  -­‐  Liquid  fuels 1,9 1,0 CP0454  -­‐  Solid  fuels 0,6 1,0 CP0455  -­‐  Heat  energy 1,4 1,0 Total  allocation  of  CP04 80,1 CP05 CP051  -­‐  Furniture  and  furnishings,  carpets
APPENDIX  J:  SUB-­‐CAT.  EXPENSES  CP04-­‐ 05       17/22 CP0511  -­‐  Furniture  and  furnishings 36,5 CP0512  -­‐  Carpets  and  other  floor  coverings 5,4 0,4 CP0513  -­‐  Repair  of  furniture,  furnishings   and  floor 0,9 CP052  -­‐  Household  textiles CP053  -­‐  Household  appliances CP0531  -­‐  Major  household  appliances 10,1 0,4 CP0532  -­‐  Small  electric  household   appliances 1,4 CP053  -­‐  Repair  of  household  appliances 2,0 CP054  Glassware,  tableware  and  utensils 6,1 CP055  -­‐  Tools  and  equipment  for  house,   garden 7,0 CP0551  -­‐  Major  tools  and  equipment 1,5 CP0552  -­‐  Small  tools  and  miscellaneous  acc. 5,5 CP056  -­‐  Goods  and  services  for  routine 22,9 CP0561  Non-­‐durable  household  goods 14,7 CP0562  -­‐  Domestic  services  and  household   ser. 8,2 Total  allocation  of  CP05 6,2
  APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)   18/22   APPENDIX K: SUB-CAT. EMISSSIONS CP04-05 (EIPRO) Distribution of environmental pressure in the sub-categories of CP04-05 in four impact categories. Green marks categories allocated to the dwelling. Global  warmning  potential   CP04-­‐05  -­‐  Housing  etc.   CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 4,7 19,9 A31 New  residential  1unit  structure,  nonfarm 3,2 13,6 A333 (washing  with)  household  laundry  equipment 2,4 10,2 A33 New  additions  &  alterations,  nonfarm,  construction 1,8 7,6 A332 (Use  of)  household  refriferators  and  freezers 1,8 7,6 A337 (use  of)  electric  lamp  bulbs  and  tubes 1,2 5,1 A331 (use  of  )  household  cooking  equipment 1 4,2 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,7 3,0 A413 Water  supply  and  seweage  systems 0,7 3,0 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,7 3,0 A393 Non-­‐durable  household  goods 0,5 2,1 A106 Carpets  and  rugs 0,3 1,3 A139 Wod  household  furniture,  except  upholstered 0,3 1,3 A149 Parittions  and  fixtures,  except  wood 0,3 1,3 A201 Miscellaneous  plastic  products,  n.e.c 0,3 1,3 A437 Miscellaneous  equipment  rental  and  leasing 0,2 0,8 A117 Housefurnishings,  n.e.c 0,2 0,8 A439 Other  buisness  services 0,2 0,8 A335 (use  of)  household  vacuum  cleaners 0,2 0,8 A142 Upholsteres  household  furniture 0,2 0,8 A334 (use  of)  electric  housewares  and  fans 0,2 0,8 A17 Forestry  proudcts 0,2 0,8 A25 Crude  petreoleum  and  natural  gas 0,2 0,8 A429 Electrical  repair  shops 0,1 0,4
APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS   CP04-­‐05    (EIPRO)       19/22 A144 Mattresses  and  bedsprings 0,1 0,4 A430 Watch,  clock,  jewlry  and  furniture  repair 0,1 0,4 A123 Fabricated  textile  products,  n.e.c 0,1 0,4 A148 Woodd    partitions  and  fixtures 0,1 0,4 A121 Automotive  and  apparel  trimmings 0,1 0,4 63 Other  categories,  total 1,5 6,4 SUM  of  allocation  to  building 10,9 47,0 Photochemical  oxidation CP04-­‐05  -­‐  Housing  etc. CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 3,8 17,3 A31 New  residential  1unit  structure,  nonfarm 3,8 17,3 A333 (washing  with)  household  laundry  equipment 1,1 5,0 A33 New  additions  &  alterations,  nonfarm,  construction 2,1 9,5 A332 (Use  of)  household  refriferators  and  freezers 0,8 3,6 A337 (use  of)  electric  lamp  bulbs  and  tubes 0,4 1,8 A331 (use  of  )  household  cooking  equipment 0,6 2,7 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,9 4,1 A413 Water  supply  and  seweage  systems 0,6 2,7 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,7 3,2 A393 Non-­‐durable  household  goods 0,8 3,6 A106 Carpets  and  rugs 0,6 2,7 A139 Wod  household  furniture,  except  upholstered 0,4 1,8 A149 Parittions  and  fixtures,  except  wood 0,3 1,4 A201 Miscellaneous  plastic  products,  n.e.c 0,5 2,3 A437 Miscellaneous  equipment  rental  and  leasing 0,3 1,4 A117 Housefurnishings,  n.e.c 0,4 1,8 A439 Other  buisness  services 0,3 1,4 A335 (use  of)  household  vacuum  cleaners 0,2 0,9 A142 Upholsteres  household  furniture 0,3 1,4 A334 (use  of)  electric  housewares  and  fans 0,1 0,5
  APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)   20/22   A17 Forestry  proudcts 0,2 0,9 A25 Crude  petreoleum  and  natural  gas -­‐ -­‐ A429 Electrical  repair  shops 0,2 0,9 A144 Mattresses  and  bedsprings 0,2 0,9 A430 Watch,  clock,  jewlry  and  furniture  repair 0,2 0,9 A123 Fabricated  textile  products,  n.e.c 0,2 0,9 A148 Woodd    partitions  and  fixtures 0,1 0,5 A121 Automotive  and  apparel  trimmings 0,2 0,9 A116 Curtains  and  drapiers 0,1 0,5 A143 Matal  household  furniture 0,1 0,5 A145 Wood  office  furniture 0,1 0,5 A32 New  residential  2-­‐4unit  structures,  nonfarm 0,1 0,5 A151 Furniture  and  fixtures,  nec 0,1 0,5 59 Other  categories,  total 1,2 5,5 SUM  of  allocation  to  building 11 50 Eutrophication       CP04-­‐05  -­‐  Housing  etc.       CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 1 10,1 A31 New  residential  1unit  structure,  nonfarm 1,2 12,1 A333 (washing  with)  household  laundry  equipment 0,6 6,1 A33 New  additions  &  alterations,  nonfarm,  construction 0,7 7,1 A332 (Use  of)  household  refriferators  and  freezers 0,4 4,0 A337 (use  of)  electric  lamp  bulbs  and  tubes 0,3 3,0 A331 (use  of  )  household  cooking  equipment 0,2 2,0 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,3 3,0 A413 Water  supply  and  seweage  systems 0,2 2,0 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,2 2,0 A393 Non-­‐durable  household  goods 0,8 8,1 A106 Carpets  and  rugs 0,7 7,1 A139 Wod  household  furniture,  except  upholstered 0,1 1,0
APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS   CP04-­‐05    (EIPRO)       21/22 A149 Parittions  and  fixtures,  except  wood 0,1 1,0 A201 Miscellaneous  plastic  products,  n.e.c 0,1 1,0 A437 Miscellaneous  equipment  rental  and  leasing 0,1 1,0 A117 Housefurnishings,  n.e.c 0,7 7,1 A439 Other  buisness  services 0,1 1,0 A335 (use  of)  household  vacuum  cleaners 0,1 1,0 A142 Upholsteres  household  furniture 0,3 3,0 A334 (use  of)  electric  housewares  and  fans 0,1 1,0 A17 Forestry  proudcts 0,2 2,0 A25 Crude  petreoleum  and  natural  gas -­‐ -­‐ A429 Electrical  repair  shops -­‐ -­‐ A144 Mattresses  and  bedsprings 0,1 1,0 A430 Watch,  clock,  jewlry  and  furniture  repair 0,1 1,0 A123 Fabricated  textile  products,  n.e.c 0,2 2,0 A148 Woodd    partitions  and  fixtures -­‐ -­‐ A121 Automotive  and  apparel  trimmings 0,2 2,0 A116 Curtains  and  drapiers 0,2 2,0 A182 Chemicals  and  chemical  preparations,  n.e.c 0,1 1,0 A120 Pleating  and  stiching 0,1 1,0 63 Other  categories,  total 0,4 4,0 SUM  of  allocation  to  building 3,4 34,3 Acidification CP04-­‐05  -­‐  Housing  etc. CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 2,7 10,5 A31 New  residential  1unit  structure,  nonfarm 3 11,7 A333 (washing  with)  household  laundry  equipment 4 15,6 A33 New  additions  &  alterations,  nonfarm,  construction 1,8 7,0 A332 (Use  of)  household  refriferators  and  freezers 3 11,7 A337 (use  of)  electric  lamp  bulbs  and  tubes 2,2 8,6 A331 (use  of  )  household  cooking  equipment 1,5 5,8 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,7 2,7
  APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)   22/22   A413 Water  supply  and  seweage  systems 0,6 2,3 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,7 2,7 A393 Non-­‐durable  household  goods 0,5 1,9 A106 Carpets  and  rugs 0,3 1,2 A139 Wod  household  furniture,  except  upholstered 0,3 1,2 A149 Parittions  and  fixtures,  except  wood 0,3 1,2 A201 Miscellaneous  plastic  products,  n.e.c 0,2 0,8 A437 Miscellaneous  equipment  rental  and  leasing 0,2 0,8 A117 Housefurnishings,  n.e.c 0,2 0,8 A439 Other  buisness  services 0,2 0,8 A335 (use  of)  household  vacuum  cleaners 0,3 1,2 A142 Upholsteres  household  furniture 0,2 0,8 A334 (use  of)  electric  housewares  and  fans 0,3 1,2 A17 Forestry  proudcts 0,2 0,8 A25 Crude  petreoleum  and  natural  gas -­‐ -­‐ A429 Electrical  repair  shops 0,1 0,4 A144 Mattresses  and  bedsprings 0,1 0,4 A430 Watch,  clock,  jewlry  and  furniture  repair 0,1 0,4 A123 Fabricated  textile  products,  n.e.c -­‐ -­‐ A148 Woodd    partitions  and  fixtures 0,1 0,4 A121 Automotive  and  apparel  trimmings 0,1 0,4 Fabricated  textile  proudcts 0,1 0,4 65 Other  categories,  total 1,7 6,6 SUM  of  allocation  to  building 8,8 34,2   Average  of  previous  four  categories   SUM  of  allocation  to  building 8,5 41,4

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Master's thesis: The absolute sustainable building

  • 1. THE ABSOLUTE SUSTAINABLE BUILDING DEFINING SUSTAINABILITY BASED ON ENVIRONMENTAL CARRYING CAPACITY J Master’s thesis Kathrine Nykjær Brejnrod Student ID: 20062459 Architectural engineering Aarhus University, Department of Engineering
  • 3. TITLE: THE ABSOLUTE SUSTAINABLE BUILDING DEFINING SUSTAINABILITY BASED ON ENVIRONMENTAL CARRYING CAPACITY PROJECT TYPE: MASTER’S THESIS IN: ARCHITECTURAL ENGINEERING – INTEGRATED ENERGY DESIGN MADE BY: KATHRINE NYKJÆR BREJNROD STUDY NR.: 20062459 CONTACT: [email protected] +45 20300601 PROJECT PERIOD: JANUARY 26. – JUNE 1. 2015 SUPERVISOR: STEFFEN PETERSEN, AARHUS UNIVERSITY CO-SUPERVISOR: MORTEN BIRKVED, TECHNICAL UNIVERSITY OF DENMARK Date and signature PREFACE: This thesis is the result of 4 months of research, modelling and analysis in fulfilment of the requirements for the MSc. Architectural Engineering – Integrated energy design at Aarhus University (AU). The thesis consists of the current report with an appendix report in direct continuation. I thank Pradip Kalbar at DTU for valuable guidance, SBI for supplying background data on the reference cases used in the study as well as Charlotte Darre for proofreading. Special thanks to Morten Birkved, at Quantitative Sustainability assessment at DTU management, for generous guidance and valuable discussions.
  • 5. ABSTRACT Today the environment is under immense pressure from anthropogenic activities, and the building sector plays an important role in reducing this pressure. The current assessments of building sustainability are based on relative measures related to current practice. The purpose of this study is to present a sustainability assessment for buildings based on the impacts relative to the environmental carrying capacity. The study identifies three methods for identifying a “fair share” of the environmental carrying capacity in 11 impact categories that should be allocated to a dwelling. A normalisation of the buildings impacts compared to this fair share thus formed the basis of the absolute sustainable assessment. The absolute sustainability assessment was carried out on two reference cases, namely a standard house representing the prevalent Danish single-family house in both size and construction type and a building representing state-of-the-art in realtion to reducing environmental impacts from materials. The assessment showed that both buildings were far from absolute sustainability. The carrying capacities were immensely transgressed on climate change and freshwater eutrophication for both buildings. Further more the impact on both water depletion and freshwater ecotoxicity were approaching the limits for both the Standard house and the Upcycle house. Three scenarios for the standard house to reach absolute sustainability in 2050 were projected. The common denominator for the three scenarios were the immense reductions needed, and for instance if the living area were reduced by 40% by 2050, the impacts from use phase energy should be reduced with 93% and the same reduction would be needed for the impacts from materials and construction to reach absolute sustainability
  • 6. RESUMÉ Miljøet er i dag under stærkt pres på grund af menneskeskabte påvirkninger. I kampen for at reducere dette pres spiller bygge sektoren en vigtig rolle i forhold til at udvikle bæredygtige løsninger, der kan reducere miljøbelastningen fra det byggede miljø. Definitionen af bæredygtigt byggeri er i dag baseret på relative mål defineret ud fra nuværende praksis og ikke relateret til naturens ressourcer og kapacitet. Formålet med dette studie er at udvikle en metode, til vurdering af bygningers absolutte bæredygtighed ud fra en sammenligningen af de miljømæssige påvirkninger sammenholdt med den egentlige miljømæssige bæreevne. Studiet præsenterer tre metoder, der identificerer en ”fair del” af den miljømæssige bæreevne som kan allokeres til bygningen i 11 påvirkningskategorier. Bygningens totale påvirkning i hver kategori normaliseres i forhold til den allokerede miljømæssige bæreevne for at vurdere om bygningen er absolut bæredygtig. Derudover benyttes to casestudier som grundlag for at vurdere om dansk boligbyggeri ligger inden for den miljømæssige bæreevne og derved kan betegnes som absolut bæredygtig. Den ene case er et standard hus, der repræsenterer et gængs dansk parcelhus både i forhold til størrelse og materialevalg, Standard huset, og den anden case er et parcelhus der repræsenterer state-of-the-art i forhold til nedbringelse af miljøaftrykket fra bygningens materialer, Upcycle huset. Analysen viste at begge huse var langt fra målet om absolut bæredygtighed. Både standard huset og Upcycle husets påvirkninger overskred bæreevnen langt for både klima ændring og ferskvands eutrofiering. Derudover nærmede begge huses påvirkninger på både vandmangel og ferskvands-økotoksicitet sig bæreevnen. Studiet viser desuden, hvordan standard huset kan opnå absolut bæredygtighed i 2050 igennem en fremskrivning af påvirkningen fra energiforbrug, materialer og opførsel samt antal bebyggede kvadratmeter per person. Den nødvendige reduktion for at opnå absolut bæredygtighed i 2050 vil for eksempel betyde en reduktion på 93% på påvirkningen per kvadratmeter fra både energiforbrug samt materialer og opførsel.
  • 7. TABLE OF CONTENTS 1   INTRODUCTION  ..................................................................................................................................................  1   2   LITERATURE  STUDY  .........................................................................................................................................  4   2.1   SUSTAINABILITY  AND  THE  BUILDING  SECTOR  ................................................................................................................  4   2.2   CURRENT  BUILDING  SUSTAINABILITY  ASSESSMENTS  ....................................................................................................  5   2.3   COUPLING  SUSTAINABILITY  AND  CARRYING  CAPACITY  ..............................................................................................  10   2.4   ENVIRONMENTAL  CARRYING  CAPACITY  ........................................................................................................................  12   2.5   HYPOTHESES  TEST  ............................................................................................................................................................  14   3   METHOD  ..............................................................................................................................................................  15   3.1   REFERENCE  BUILDINGS  ....................................................................................................................................................  16   3.2   LCA  METHODOLOGY  .........................................................................................................................................................  17   3.3   VALIDATION  OF  MODEL-­‐BUILD  UP  .................................................................................................................................  20   3.4   ALLOCATION  OF  CARRYING  CAPACITY  ...........................................................................................................................  21   3.5   SENSITIVITY  ANALYSIS  .....................................................................................................................................................  35   4   RESULTS  ..............................................................................................................................................................  37   4.1   CARRYING  CAPACITY  FOR  A  SINGLE-­‐FAMILY  HOUSE  ...................................................................................................  37   4.2   CURRENT  ENVIRONMENTAL  PRESSURE  FROM  DWELLINGS  .......................................................................................  38   4.3   USE  PHASE  ENERGY  ..........................................................................................................................................................  46   4.4   BUILDING  LIFETIME  ..........................................................................................................................................................  48   4.5   VALIDATION  OF  MODEL  BUILD-­‐UP  .................................................................................................................................  49   4.6   SENSITIVITY  ANALYSIS  .....................................................................................................................................................  51   5   DISCUSSION  ........................................................................................................................................................  53   5.1   ALLOCATION  OF  THE  CARRYING  CAPACITY  ..................................................................................................................  53   5.2   ENVIRONMENTAL  PRESSURE  FROM  CURRENT  CONSTRUCTION  METHODS  .............................................................  55   5.3   VALIDATION  OF  MODEL  BUILD-­‐UP  .................................................................................................................................  56   5.4   THE  ABSOLUTE  SUSTAINABLE  BUILDING  ......................................................................................................................  57   5.5   UNCERTAINTIES  AND  FUTURE  WORK  ............................................................................................................................  65   6   CONCLUSION  AND  RECOMENDATIONS  .....................................................................................................  69   7   REFERENCES  ......................................................................................................................................................  71   APPENDIX  REPORT  IN  CONTINUATION  OF  THE  MAIN  REPORT  
  • 9. INTRODUCTION       1/74 1 INTRODUCTION Today our climate and ecosystems are under an immense pressure, and as a result of this we experience increasing temperatures, waste assimilation in oceans, air pollution as well as a stark increase in biodiversity loss just to mention some of the more obvious effects. We need more than 1,5 planet earths to sustain the current way of life, implying that the pressure on earth overshoots the capacity by more than 50% (Global Footprint Network, 2010). Today there is scientific consensus on identifying anthropogenic activities as the main driver behind these changes (DiMento & Doughman, 2007), but easing the pressure on both climate and ecosystems seems a severe challenge opposed by several key factors such a globally increasing population, constantly rising consumption levels, poverty and inequality problems as well as current financial and economic structures. In the attempt to reduce the human impact on both climate and environment the building sector plays a key role. The building sector stands for 40% of the global energy use and around 1/3 of the global green house gas emissions. Further more the building sector has been identified as the sector with the largest potential for significantly reducing green house gas emissions compared to other high-emission sectors. (UNEP, 2009). In 1987 the first general definition of sustainability emerged in the Brundtland report, defined as the level of development meeting the needs of the present without compromising the ability of future generations (UN, 1987). Later on, with the Rio declaration the description evolved into a sustainability definition containing three main pillars; environmental, social and financial sustainability. In the 1990s a rising public awareness on anthropogenic climate changes and the need for change also reached the construction industry, and through out the 90s a number of environmental rating systems for buildings arose. Today the list of terms describing sustainable buildings is long and includes words such as green buildings, zero-carbon buildings and eco-design. Buildings can be certified according to a range of different building assessment schemes today, with most of them leading to a rating on a scale, ie. from bronze to gold. Todays building assessment schemes are basing their sustainability definitions on current practice and many of the environmental parameters evaluated are based on ‘per area’ impacts. The assessment schemes thus does not encounter the current environmental means, the decrease in environmental means due to increasing populations or the quantity of the resulting environmental impact from the construction industry. But can a building’s environmental load be considered sustainable, when it is not related to actual environmental means of our world, but just defines a building as somewhat better than the rest? The project will try to relate the definition of environmental sustainable buildings to a framework based on the environmental carrying capacity of the earth. In this way the project will try to illuminate the actual
  • 10.   INTRODUCTION   2/74   environmental means that is available for our buildings, and in that way be able to define a more absolute framework for sustainable buildings compared to todays more relative measures. To delineate the project, the focus will be on sustainability of Danish dwellings, and the main hypotheses will be:     1# ‘The environmental impact from Danish dwellings affects the environment to an extent that lies beyond a fair share of the earth’s environmental carrying capacity.’ 2# ‘Based on the environmental carrying capacity an absolute framework for sustainable buildings can be developed.’ The environmental carrying capacity here refers to the maximum pressure that a natural system can sustain without risking irreversible changes. The environment is constantly assimilating waste, cleansing the waters, dissolving and absorbing huge quantities of emissions as well as regenerating natural resources. All of these abilities are crucial for the survival and well being of flora and fauna, including humanity. For all of these regenerative forces apply that the environment only has a limited capacity, and when the pressures exceeds the capacity waste starts accumulating, concentration of air pollutants and green house gasses rises and the amount of natural resources declines. The carrying capacity thus defines the operating space within the environmental capacity assuring that the pressures do not create changes that are irreversible. The absolute framework for sustainable buildings is based on an assessment of the buildings impact in relation to the environmental carrying capacity, in contrast to today’s sustainability definition where an assessment of building sustainability is related to impacts of the current practice. TODAY ABSOLUTE Figure 2 Illustration of the sustainable buildings according to todays relative definition and the absolute definition of sustainable buildings By focusing on defining a framework for absolute environmentally sustainable buildings the project aims at defining a quantitative goal for the current development of environmentally sustainable buildings, and Current practice Environmental capacity Figure 1 Main hypothesis of the study  
  • 11. INTRODUCTION       3/74 thereby enabling a basis for better and more qualified discussions and enlightened decision making in building design and engineering. A literature study was carried out to examine if other studies had already investigated a similar hypothesis and to give the author an insight into studies related to the hypotheses. The literature study thus investigated whether the hypotheses were relevant to investigate further or if they needed to be trimmed or expanded. When the hypotheses were final, a method for investigating the hypotheses were developed and the analysis were carried out. This general method approach is illustrated in Figure 3.                 Figure 3 General method approach for investigating the hypothesis
  • 12.   LITERATURE  STUDY   4/74   2 LITERATURE STUDY The following chapter is a literature study carried out to test the hypotheses relevance. If the reader wishes to skip this, a summary of the findings of the literature study can be found in section 2.5 while the project method and findings are described from chapter 3 onwards. 2.1 Sustainability and the building sector With the energy crisis in the 1970s energy savings became an important topic, and energy related building regulations became an important tool in restricting the energy loss from buildings (Weissenberger et al., 2014). Then again in the 1990s a rising public awareness on the anthropogenic climate changes and a focus on environmental policies, led the building sector to recognize the need for changes in the way buildings were designed, built and operated (Haapio & Viitaniemi, 2008). The increased focus on reducing the environmental impact of buildings was followed by the emergence of terms describing buildings with reduced environmental impact, such as; green buildings, zero energy buildings or low-carbon buildings. In line with the increased focus on environmental effects the first building environmental rating system arose in the 90s, allowing an assessment of the environmental impacts of the whole building and offering the stakeholders a certification of their building projects. This focus on reducing the environmental impact from the built environment, has thus until recent years continued to primarily focus on reducing the operational energy. This has mainly been in the form of higher insulation standards as well as increased efficiencies, but in the later years also by adding energy producing installations based on renewable energy sources. In recent years a focus on the whole life cycle perspective of the building has become more prevalent, and studies have identified the embedded energy in building materials as an important factor (Minter, 2014). A life cycle assessment (LCA) allows for an assessment of the use of resources as well as the potential environmental impacts associated with a product or service. The methodology was developed already in the late 1960s and early 1970s under the name REPA (Resource and Environmental Profile Analysis), but was at that time mainly focused at the packaging industry. In the late 90s a series of standards specifying the methodology emerged to standardize the results from the LCA, since variations in data collection, methodology and system boundaries could cause large deviations in the outcome, where the series of standards used today is the ISO 14040 and the ISO 14044. (Weissenberger et al., 2014). The diffusion of the LCA methodology has though seen gaining ground in the building sector only within recent years, even though the methodology has been known in the sector for many years, e.g. in Denmark the Building Environmental Assessment Tool (BEAT) has been available since the 1990s but has been used mainly for research purposes and not widespread in the Danish building sector as a design tool. In 2013 the
  • 13. LITERATURE  STUDY       5/74 life cycle thinking was introduced in the assessment scheme LEED where an LCA is still optional but improves the overall rating (U.S. GBC, 2015). In the assessment scheme DGNB a full LCA of the building is mandatory, and the performance in the LCA impacts the overall rating (DK-GBC, 2014). The life cycle analysis of a building is complex and challenging, and the accuracy of the results is dependent on the system boundaries but also to a large extent on the available data. Databases like ökobau and Ecoinvent provides general data for the LCA, but also more product specific input are becoming available with the environmental product declarations (EPD) (Weissenberger et al., 2014). The EPD’s are prioritized as LCA data for some of the building environmental assessments (DK-GBC, 2014; U.S. GBC, 2015), but it is still only a minority of the building products on the market that today has a verified EPD (EPD Danamark, 2015). 2.2 Current building sustainability assessments A wide range of building assessment tools offers evaluation and certification of a building’s sustainability. Following is a brief description of some of the assessment tools currently prevalent on the market. LEED. Leadership in Energy & Environmental Design (LEED) was developed in the U.S in 2000 by the U.S. Green Building Council, and is today most prevalent in North America (Giama & Papadopoulos, 2012). It consists of 8 primary credit categories: • Location and transportation • Materials and resources • Water efficiency • Energy and atmosphere • Sustainable site • Indoor environmental quality • Innovation • Regional priority Within each category there is specific prerequisites as well as a number of potential extra points to gain, and based on its performance a project can obtain one out of four levels of certification ranging from certified to platinum. (U.S. GBC, 2015). During a project, the design team members can track their progress in the categories towards a LEED ranging without the need of special LEED consultants (Aysin, 2011). BREEAM. Building Research Establishment Environmental Assessment Method (BREEAM) was established in 1990 in the U.K as the first tool assessing the environmental performance of the whole building (Aysin, 2011; Haapio & Viitaniemi, 2008). Together with LEED it is today the most widespread assessment scheme (Giama & Papadopoulos, 2012), with 425.000 certified buildings worldwide (BREEAM, 2015). BREEAM consists of 9 primary credit categories: • Management • Health and wellbeing • Energy • Transport • Water • Materials • Waste • Land use • Ecology and pollution Based on a projects score in each category it can be certified on a scale from pass to outstanding.
  • 14.   LITERATURE  STUDY   6/74   DGNB. Deutches Gesellschaft für Nachhaltiges Bauen (DGNB) was developed in 2009 in Germany by the German government and the German Sustainable Building Council. It consists of 6 key areas: • Environmental quality • Economical quality • Sociocultural and functional quality • Technical quality • Process quality • Site quality Based on the score in the categories a project can be certified bronze, silver or gold. It requires though a minimum score in each individual category to obtain the certification, why a high average score is not necessarily sufficient. (DGNB, 2015; Giama & Papadopoulos, 2012) Though the DGNB is becoming more widespread in countries such as Germany and Denmark, only a small fraction of todays building stock in these countries have been certified according the scheme. In Denmark 219 DGNB consultants and 19 auditors have been trained, but only 10 buildings have been certified (DK- GBC, 2015). DGNB certification is still new on the Danish market, but the same tendency is seen on the German market, where DGNB has been available since 2009. In Germany around 400 consultants and 650 auditors have been trained, but the amount of certified buildings is still only around 300 (DGNB, 2015). SBTool. The Sustainable Building Tool (SBTool) was developed in 1996 (then as GBTool) by a correlation of 14 countries. The SBTool is a generic framework that allows local organisations to develop their own rating system, and is designed to allow for designers reflection on different priorities and adapt the scheme to environmental, socio-cultural as well as economic and technological aspects of a specific region. (Aysin, 2011; Matheus & Bragança, 2011). The system scope is flexible and can be modified to include from a few dozen to more than 100 evaluation criteria (iiSBE, 2015). CASBEE. Comprehensive Assessment System for Built Environment Efficiency (CASBEE) was developed in Japan and launched in 2001 by the Japanese Sustainable Building Consortium. It assesses the ratio between the building environmental quality and performance (e.g. energy efficiency) and the building environmental loads (e.g. global warming potential). (Giama & Papadopoulos, 2012). CASBEE covers four main areas; energy efficiency, resource efficiency, local environment and indoor environment, which are then all re-categorized into respectively load and quality parameters (CASBEE, 2015). The tool is very thoroughly and in the study by Siew et al. (2013) comparing different assessment schemes CASBEE has the highest methodology score, but due to its comprehensive nature its extremely difficult to implement and lacks applicability and popularity compared to e.g. LEED and BREEAM (Aysin, 2011). The assessment tools described above are just a selection of some of the many currently available building assessment methods. Most of the assessment tools are commercial, and they tend to focus on economic and financial motivation as a driver for the developers and other stakeholders to obtain the certification (Giama & Papadopoulos, 2012), but the certification of a building could also create a positive signalling effect for the stakeholder to the surrounding society (Beradi, 2012). The economic benefits of a certification in form of lower maintenance and running cost, higher productivity, increased property value etc. though needs to make up for the higher investment cost as well as the considerable cost of the actual certification, if the motivational factor is financial (Giama & Papadopoulos, 2012).
  • 15. LITERATURE  STUDY       7/74 2.2.1 Criteria and weighting As described previously most of the assessment schemes seem to focus on the same main evaluation criteria; energy efficiency, material and resources, indoor environmental quality, waste and pollution, site selection and water efficiency (Beradi, 2012), and recently aspects such as economic and social value have also been included. An important factor though is how each method chooses to weigh the different criteria according to each other (Giama & Papadopoulos, 2012) as well as how the thresholds in the various criteria are derived. The different criteria are given a certain weight before being summarized into a total score, and the weighting therefor implies the significance and importance of the different criteria. In a study by Beradi (2012) different assessment schemes were compared and evaluated, including BREEAM, LEED, CASBEE and SBTool. The study showed how energy efficiency was considered the most important criteria and therefore given most weight in all of the included schemes. Weighing is thus an important factor in all assessments schemes since it dominates the overall performance score of the building, but is at the same time one of the most theoretically controversial aspects within the sustainable buildings assessments (Sharifi & Murayama, 2013; Kajikawa et al., 2011). The reasons behind the choice of criteria as well as the weighing are often not very transparent (Beradi, 2012), and according to Kajikawa et al. (2011) some choose a consensus-based weighting in the absence of a scientifically based weighting method. For example CASBEE seems to derive its weighing from a survey of building owners, operators and designers, where BREEAM derives it from a combination of consensus-based weightings as well as a ranking by a panel of experts. (Siew et al., 2013). When dealing with the criteria weighing in the building assessment schemes the literature relating to this seems profound both in terms of comparative studies as well as identification of limitations and challenges. In relation to the establishment of the criteria thresholds, on the other hand, the extent of literature seems far less extensive. Concerning the environmental criteria they seem to keep pace with the legislative development together with current best practice (Kajikawa et al., 2011; Giama & Papadopoulos, 2012), and as defined by Kajukawa et al. (2011) the primary role of the environmental assessment is to provide a comprehensive assessment of the environmental characteristics of a building, using a common and verifiable set of criteria and targets for buildings owners and designers to achieve a higher environmental standard. The threshold is thus seen to rely on current best practice, why the values are seen to be more relative than absolute, and the thresholds seem to follow a technological development rather than relying on scientific definitions of sustainable thresholds. Even though it is difficult to define the ideal criteria for sustainability, it seems clear that the different rating systems suggest advisable actions in the development towards sustainability in the building sector (Kajikawa et al., 2011), and at the same time the assessment schemes help to increase the awareness of the need for reducing the environmental impact from buildings. To exemplify the criteria weighing as well as the criteria thresholds, the Danish version of the DGNB assessment scheme is used as a basis. The manual behind the DGNB certification of office buildings in
  • 16.   LITERATURE  STUDY   8/74   Denmark has recently been released, which enables others than DGNB-auditors to see and assess the actual thresholds as well as the criteria weighing (DK-GBC, 2015). The following is thus a brief review of the most significant elements in relation to criteria weighing and threshold establishing within the environmental criteria in the DGNB Denmark. 2.2.1.1 Criteria weighing in DGNB-DK Environment is one of the five main areas in DGNB, and is granted a weight of 22,5%. The area Environment is divided into a range of criteria, see Table 1 Overview of the criteria of the main area "Environmental quality" in DGNB-DK. The criterion has a total weight of 22,5% in the overall rating. Sub criterion Description Part of total rating LCA – environmental impact Reducing the environmental impact from the building throughout its life cycle. 7,9% Environmental risks related to constructional parts Reducing the use of harmful substances such as heavy metals. 3,4% Environmental impact from the extraction of materials Protection of forests, prohibition of child labour and compliance with social and environmental standards in relation to recovery of natural stone. 1,1% LCA – primary energy Reducing the primary energy demand and increasing the share of renewable energy. 5,6% Drinking water consumption and wastewater discharge Reducing water consumption and wastewater discharge, so the burden on the natural water cycle is reduced to its minimum. 2,3% Efficient land use Reducing the use of new areas for urban purposes, to make sure the land is used efficiently and that the buildings contribute to an environmental improvement of the land area. 2,3% . There are two criteria involving LCA within the main area Environment; LCA-environmental impact and LCA-primary energy. Where the first one is concerning the environmental impact from construction material etc., and the second one the primary energy demand. The environmental impact from the building materials is seen to receive a total weight of 7,9% in the overall rating of the building, and the primary energy demand 5,6%.
  • 17. LITERATURE  STUDY       9/74 Table 1 Overview of the criteria of the main area "Environmental quality" in DGNB-DK. The criterion has a total weight of 22,5% in the overall rating. (DK-GBC, 2014) Sub criterion Description Part of total rating LCA – environmental impact Reducing the environmental impact from the building throughout its life cycle. 7,9% Environmental risks related to constructional parts Reducing the use of harmful substances such as heavy metals. 3,4% Environmental impact from the extraction of materials Protection of forests, prohibition of child labour and compliance with social and environmental standards in relation to recovery of natural stone. 1,1% LCA – primary energy Reducing the primary energy demand and increasing the share of renewable energy. 5,6% Drinking water consumption and wastewater discharge Reducing water consumption and wastewater discharge, so the burden on the natural water cycle is reduced to its minimum. 2,3% Efficient land use Reducing the use of new areas for urban purposes, to make sure the land is used efficiently and that the buildings contribute to an environmental improvement of the land area. 2,3% In each criterion a number of points is awarded based on a rating of the projects performance, which is then again weighed into a compliance rate. To achieve the lowest certification grade, bronze, the project needs to have an overall compliance rate of 50% though with a minimum of 35% in all five main areas, and to achieve the highest grade, gold, the overall compliance rate should be 80% with a minimum of 65% in all areas. (DK-GBC, 2014) 2.2.1.2 Thresholds in DGNB-DK When the projects performance within each criterion is evaluated it is based on a lower limit value (the minimum threshold), a reference value (good practice) and a target value (best practice) defined by DK-GBC (2014). The definitions of respectively the minimum threshold and the target value for the criterion LCA- environmental is seen for the five evaluated impact categories from Table 2. When looking at climate change (GWP) the minimum threshold for a certification is seen to be 140% of the reference building, and the target value (best practice) is seen to be 70% of the reference.
  • 18.   LITERATURE  STUDY   10/74   Table 2 Threshold values relative to impact of the DGNB reference in the criterion LCA-Environmental impact Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Photochemical Ozone Creation Potential), Acidification Potential (AP) and Eutrophication Potential (EP). (DK-GBC, 2014) GWP ODP POCP AP EP Minimum 140% 1000% 200% 170% 200% Reference 100% 100% 100% 100% 100% Target 70% 70% 70% 70% 70% When looking at the primary energy demand the same tendencies are seen, see Table 3. For the non- renewable energy the minimum value is defined as 140% of the reference and the target value is defied as 70% of the reference. At the total energy demand the target value though is seen to be defined as 40% of the reference. Table 3 Threshold values relative to the impact of the DGNB reference in the subcriterion LCA-Primary energy (DK-GBC, 2014) Non-renewable energy Total energy demand Minimum 140% 140% Reference 100% 100% Target 70% 40% In the two former sub-criteria, it is thus seen that the maximum point is given for at reduction of respectively 30% and 60% of the established reference building depending on the impact category. As described previously the thresholds for the reference building are set up according to reference values in relation to current practice, but when it concerns the more exact basis on which basis these reference values have been derived no information could be found. The minimum value is seen varying from 100% to 200% of the impact of the reference building depending on the impact category, and depending on the project’s performance in other criteria this could be enough for a DGNB certification. Since the certification is based on an overall assessment of the buildings performance, a building performing equal to or worse than the reference building in the two discussed criteria would be certifiable. 2.3 Coupling sustainability and carrying capacity As identified in the previous section the definition of environmentally sustainable buildings in the assessment schemes seem to rely on thresholds related to current practice, and the development seem to progress with the technological development without a specific target in sight. The environmental load of a
  • 19. LITERATURE  STUDY       11/74 building is thus related to the load of a reference building and not to a scientific baseline when evaluating if a building is sustainable or not. In a study by Olgay & Herdt (2004) the need for an identification of criteria based on a scientific understanding of environmental capacity instead of the current practice in traditional environmental impact assessment was identified, but to the knowledge of the author, literature identifying methods for this coupling of building impact and environmental capacity is almost non-existing. Though with the exception of one scientific paper by Bendewald and Zhai (2013), where a method of evaluating if a building is sustainable based on the building’s environmental impact together with the environmental carrying capacity of the site associated to the building is presented. The method balances the building’s carbon emissions throughout the building lifetime with the sites carbon balance throughout the same period, and if the building emits more carbon than the net uptake of the site, the building is considered unsustainable. (Bendewald & Zhai, 2013). Linking building sustainability with environmental carrying capacity of the site involves several obviously ambiguities though. For instance a bigger site would automatically result in a more sustainable evaluation of a building, but also the general assumption that the entire globe could be covered by buildings leaving no area for food production etc., but with an evaluation of each building as sustainable as long as the site capacity and the building impact was balanced. Looking somewhat broader than buildings, the term Ecological Footprint was introduced by William E. Rees in 1992 as a way to compare human impact on the earth (or a specific area) with the biocapacity of the same area. The Ecological footprint measures the amount of productive land and water area required to produce all resources consumed by a population (or activity) as well as for absorbing the waste (pollution etc.) generated (Global Footprint Network, 2010). The Ecological Footprint is measured in Globale Hectares (gha), which are hectares with a yield corresponding to the global average yield. When the ecological footprint for a certain area, e.g. the whole world, is found, it is compared to the actual biocapacity of the same area to visualize a potential gab between human impact and nature’s capacity. The overshoot according to the ecological footprint method is currently 1,5 planet earths. The Ecological Footprint is a popular indicator on humanity’s level of sustainability (or unsustainability) and is adopted by institutions such as the World Wild Life Fund as well as a long list of national and local environmental organizations and research institutes. The method has though received criticism in different areas. First of all for the use of the hypothetical land measure gha, which has the possibility of being intepreted as realistic or even actual land areas, and further more for assuming that all important environmental impact from humans can be indicated by land use. The ecological footprint in this way turns land scaricity into a primary concern and neglects impacts that can not directly be related to this, (Van den Bergh & Grazi, 2013). In 2013 Birkved & Goldstein presented a method combining Urban Metabolism (UM) and LCA to assess the susainability of urban systems by including both upstream and downstream effects. This combined UM-LCA
  • 20.   LITERATURE  STUDY   12/74   they further relate to the environemntal burden boundaries to enable an assessment of the absolute sustainability of the urban system. Birkved & Goldstein (2013) thus relates the environemntal impact with environemental capacity to define absolute sustainability. 2.4 Environmental carrying capacity The following sections looks into studies establishing thresholds on environmental carrying capacity to identify a basis/baseline for the further work. Humanities influence on climate change as well as changes on ecosystems are followed closely by the worlds leading scientist, and assessments from the Intergovernmental Panel of Climate Change (IPCC) as well as the Millennium Ecosystem Assessment (MEA) provides amongst others insight into these changes. For many years scientist around the world have tried to estimate and quantify both humanity’s impact on the environment and the maximum impact the earth can sustain. In 2009 Rockström et al. introduced the concept of “Planetary boundaries”, defined as; the safe operating space for humanity with respect to the earths system and in association with the planet’s biophysical subsystems and processes. These boundaries are defined for certain subsystems of the earth where the reactions are non-linear, and where a transgression of a certain threshold could take the system into a whole new state and generate unacceptable environmental change (Rockström et al., 2009), and the thresholds thus define a safe limit for the systems “tipping point”. Rockström et al. (2009) has identified nine of such systems processes for which they find a planetary boundary is needed; § Rate of biodiversity loss § Climate change § Interference with the nitrogen and phosporus circle § Stratospheric ozone depletion § Ocean acidification § Global freshwater use § Change in land use § Chemical pollution § Atmospheric aerosol loading According to Rockström et al. (2009) three of these boundaries have already been crossed; climate change, rate of biodiversity loss and interference with the nitrogen cycle, see Figure 4. For the global freshwater use, change in land use, ocean acidification and interference with the global phosphorous cycle they find that humanity might be approaching these boundaries soon.
  • 21. LITERATURE  STUDY       13/74 In a recent scientific paper Bjørn & Hauschild (2015) takes the work on carrying capacity one step further, as they present a framework of carrying capacity based normalisation references for LCA. They present 1 person equivalent (PE) as an impact equivalent to the one persons annual share of the carrying capacity for eleven impact categories. This is in contrast to the traditional normalisation where impacts are compared to society’s background impacts and not to the actual capacity. Bjørn et al. (2015) has in their study defined carrying capacity as the maximum pressure a natural system can sustain without risking irreversible changes, where irreversible changes refer to changes impossible or impractical to reverse within a human timescale. From Table 4 the normalised reference per category per person year is seen, and as the table shows the study includes a normalised reference in a global perspective as well as a European. The variations in the Global and European person equivalent capacity is due to differences in population density as well as differences in the areas total capacity. Table 4 Normalised reference based on carrying capacity of respectively the World and Europe, defined per person year. (Bjørn & Hauschild, 2015) Impact category Global Europe Terrestrial acidification [mole H+ eq] 2,3⋅103 1,4⋅103 Terrestrial eutrophication [mole N eq] 2,8⋅103 1,8⋅103 Water depletion [m3 ] 306 490 Figure 4 The green circle represents the safe operating space for the nine systems, and the red wedges referesents an estimate of the current position for each variable (Rockström et al., 2009)
  • 22.   LITERATURE  STUDY   14/74   Land use , soil erosion [tons eroded soil] 1,8 1,8 Land use, biodiversity [m2 *year] 1,5⋅104 9,5⋅103 Climate change Temperature increase, 2° [kg CO2 eq] 985 985 Radiative forcing, 1W*m2 [kg CO2 eq] 522 522 Ozone depletion [kg CFC-11 eq] 0,078 0,078 Freshwater eutrophication [kg P eq] 0,85 0,46 Marine eutrophication [kg N eq] 29 31 Photochemical ozone formation [kg NMVOC eq] 73 47 Freshwater ecotoxicity [PAF]*m3 *day 1,9⋅104 1,0⋅104 The definition of the carrying capacity within the impact categories is based on scientific consensus. However, for the category climate change they suggest two boundaries for the carrying capacity; one based on limiting global warming to 2° above pre-industrial levels and one based on reducing the radiative forcing to 1W*m2 as suggested by Rockström et al. (2009). As showing from Table 4 the two differs almost by a factor two, where the boundary based on the radiative forcing is seen to be the most precautionary. The study relates the carrying capacity in each category to the actual impact. In most of the categories the relation between the capacity and the impact is bigger when only Europe is considered compared to a global scale, suggesting that the environmental pressure compared to the size of the carrying capacity of Europe is higher than the average for the rest of the world. When looking at Europe the study found the impact exceeded the capacity in three categories; land use (soil erosion), climate change as well as photochemical ozone formation. (Bjørn & Hauschild, 2015) 2.5 Hypotheses test From the literature study it has been clarified how current building assessment schemes defines sustainable buildings relative to the environmental pressure from current construction methods, and therefor not in relation to actual environmental capacity. Further it showed how the coupling of building sustainability and environmental capacity is almost non-existing in the literature, but though present to a limited extent in other aspects, i.e. Urban systems. The literature study has thus neither confirmed nor ruled out the hypotheses, but the literature study has verified the need for environmental benchmarks within the carrying capacity of the earth, and the hypotheses is therefore found highly relevant for further investigation. Further more the literature study gave an insight into relevant work in relation to establishing the environmental carrying capacity, which will form an important basis for the further work into testing the hypotheses.
  • 23. METHOD       15/74 3 METHOD A methodological framework is evolved to investigate the hypotheses stated in section 0, with the following three activities forming the basis: 1) Allocation of environmental carrying capacity to a dwelling 2) Estimation of current environmental pressures from a dwelling 3) Analysis investigating possible solutions for reaching absolute sustainable dwellings First an allocation of carrying capacity is carried out in order to identify the share that is available to a dwelling. The carrying capacity identified by Bjørn & Hauschild (2015) defines the capacities available per person. The allocation scenarios look into how large a share of one person’s capacity could be allocated to the construction and running of dwellings. The part allocated to dwellings thus forms the basis of comparison, when evaluating whether or not a dwelling is sustainable. Then to assess how the impact from new dwellings relate to the environmental capacity two reference cases are used; the ‘Standard house’ and the ‘Upcycle house’. The standard house is reflecting today’s prevalent building practice and the Upcycle house reflects today’s best practice when it comes to reducing environmental impact from materials. Through an LCA the environmental impacts of the buildings is identified and then further compared to the identified capacity allocated thereto. If the impact from the building stays within the boundaries of the allocated carrying capacity, the building is considered absolute sustainable. An analysis of the potential for attaining the absolute sustainable building is carried out to form a solution frame. Based on the analysis a range of scenarios is finally developed to identify the required changes if reaching the absolute sustainable building in 2050.
  • 24.   METHOD   16/74   3.1 Reference buildings The two case-buildings the Standard house and the Upcycle house are described in the following. A fictive location in the town of Hedensted, Denmark is assumed for both houses when performing the LCA. 3.1.1 Standard house The Standard house is a detached single-family house with a gross area of 149m2 (net area of 128m2 ) 1 . The house is one-storey and consists of: living room, kitchen, dinning room, four bedrooms, two bathrooms and a scullery. The house is built on a line foundation of concrete, with a socket of insulated lightweight concrete blocks, and the ground slab is reinforced concrete on EPS, with wooden or tiled flooring. The outer walls consist of an inner leaf of aerated concrete, mineral wool insulation and an outer leaf of masonry. The roof consists of wooden roof trusses with a solid under-roof and roofing tiles, with mineral wool as insulation and a ceiling of surface mounted plasterboards. The inner walls are aerated concrete with plaster and painted glassfelt, and timer aluminium clad windows with triple glazed panes. Facade Floorplan Materials and build up of the house in accordance with SBI (2015), and a full inventory list can be seen from appendix B. 3.1.2 Upcycle house The Upcycle house is a detached single-family house with a gross area of 129m2 (net area of 104m2 ). The house is one-storey and consists of: a living room, a kitchen, four bedrooms, one bathroom, scullery and a pantry. The house also includes a terrace and a greenhouse as an integrated part of the house. The materials used for the house are all recycled of reused products. The house is founded on screw- foundations, and two freight containers forms the bearing structure. The façade is mounted with plates of // 1 The net area is not apparent in the background report, and is therefor assumed based on the gross area Figure 5 Illustration of the standard house layout and façade. (SBI, 2015)
  • 25. METHOD       17/74 composite material and the roof with aluminium plates. The windows are triple glazed, and the internal walls and floors are covered with OSB plates. All insulation used in the house is paperwool insulation made from recycled paper waste. Facade Floorplan The Upcycle house is one of the five MiniCO2 houses in Nyborg Denmark carried out as part of a project by Realdania. Materials and the build-up of the house are according to SBI (2013), and a full inventory list can be seen from appendix A. 3.1.3 Energy consumption Both houses are built according to the Danish energy class 2015, and when nothing else is stated the energy consumption is set to 37,8 kWh/m2 /yr, and the distribution of the energy consumption is assumed to be 35% electricity and 65% heat according to SBI (2008). When simulations, with an energy consumption according to energy class 2020, are carried out the energy consumption used is 20 kWh/m2 /yr. An increased amount of insulation or additional modifications of the building design is not accounted for, and the relation between heat and electricity is assumed unaltered. For construction an energy consumption of 67,7 kWh/m2 is assumed based on a case study of a detached brick house (Cuéllar-Franca & Azapagic, 2012). The energy for construction is thus not differentiated from the Standard house to the Upcycle house. 3.2 LCA methodology LCA is initially intended for relative performance indications. The current study though is based on the more controversial use of LCA presented in the study by Bjørn & Hauschild (2015), where the results are normalised according to carrying capacity. The LCA in this study is therefore used to estimate an absolute impact from the buildings. All LCA’s are carried out using the software GaBi and based on the methodology described in the following. Figure 6 Illustration of the layout and façade of the Upcycle house (SBI, 2013)
  • 26.   METHOD   18/74   3.2.1 Functional unit When nothing else is stated the functional unit is the whole building, respectively the Standard house or the Upcycle house. The reference study period is 50 years. 3.2.2 System boundaries The system boundaries are set to include as many relevant impacts as possible through the life cycle of the building, which means they deviate in some areas from prevalent used system boundaries on building LCA. The DGNB boundaries for example leave out the construction phase with reference to an increased uncertainty. LCA of buildings usually serve a comparative purpose, i.e. benchmarking of one building to another, in which situation leaving out areas of uncertainty and eliminating deviations in assumptions can be meaningful. This study though aims to estimate the absolute impact – basically meaning the total impact of the building, and leaving out areas with great uncertainties involved, thereby excludes potentially important contributions to the absolute impact. From Figure 7 the system boundaries of the LCA on both buildings are illustrated. Building life cycle stages Production Extraction √ Transport √ Production √ Constructi on Material spilled √ Energy for cons. √ Transport √ Land conversion – site √ Maintenance − Use Replacements √ Repair √ Modifications − Operational energy √ Water − Land use – site √ End of life Transport √ Demolition (√) Waste treatment √ Recycling √ Landfill √ Figure 7 System boundaries used for the LCA. √ = included, − = not included, (√) = partial included
  • 27. METHOD       19/74 3.2.3 Background data 3.2.3.1 Building materials For the Life Cycle Inventory (LCI) different data on the building materials are needed, such as; Type of materials used, amounts of building materials used and physical properties of materials (density etc.). The type and amount of the materials in the two buildings are provided by the SBI in accordance with their work on respectively the Standard house (SBI, 2015) and the Upcycle house (SBI, 2013). When needed, physical properties of the materials such as densities and dimensions are estimated together with recycling rates of the materials, see appendix D. In the construction phase a material spill of 1% is assumed. Further more a spill of 5% of recycled material is assumed when accounting for effects from avoided production at the end of life stage. Materials for repair throughout the building lifetime 1% of the initial material amount is assumed, but only for materials exposed to the ambient environment, such as roof tiles, plaster boards etc. Repair of non-exposed materials is therefore assumed non-existent. For a detailed description of material types and amounts see appendix A and B. 3.2.3.2 Transport Two types of datasets with different boundaries are used, one “at plant” and one “at regional storage”. When using “at regional storage” all impact until regional storage are included also transport, which here is assumed identical to the site and therefore no additional transport is added. When using “at plant”, additional transport from plant to site is added since this is not included. The distances is assumed according to the recommendations by Ecoinvent (2007, p.13) when possible, and otherwise by estimates based on available information from product manufactures. Transport is included from site to disposal for all materials based on the distance from site to the nearest recycling depot. 3.2.3.3 LCI Dataset Ecoinvent 2.2 is used as the primary database for materials and processes used in the modelling. Preferably the datasets are country specific to Denmark, but this has only been available with datasets on electricity mix. Otherwise average European datasets or average Swiss datasets have been preferred. For a few more rarely used building materials Ecoinvent provided no useful dataset in which cases EPD-data are used instead. Due to different characterization methods the impacts from the EPD’s are not directly comparable, and the EPD’s are thus only used to provide data on product content, which is then modelled using Ecoinvent datasets. For a detailed description of datasets used see appendix A and B, and for the end of life flows see appendix C.
  • 28.   METHOD   20/74   3.2.4 Impact categories The following 11 impact categories are assessed in the project: § Terrestrial acidification [mole H+ eq.] § Water depletion [m3 ] § Land use – soil erosion [ton eroded soil] § Land use – biodiversity [m2 *year] § Climate change [kg CO2 eq.] § Ozone depletion [kg R-11 eq.] § Freshwater eutrophication [kg P eq.] § Marine eutrophication [kg N eq.] § Terrestrial eutrophication [mole N eq.] § Photochemical ozone formation [kg NMVOC eq.] § Freshwater ecotoxicity [PAF]*m3 *day For a short introduction to the environmental effects associated with the impact categories see appendix F. 3.2.5 Normalization The resulting impacts of the building(s) are normalised in relation to the carrying capacity allocated to the building in each specific impact category. The normalised impact (IN) for a building (B) in the impact category (i) is thus calculated as: !!,!,! = !!,! !!!",! Where I is the total impact of the building and CC is the carrying capacity allocated to the specific building type (BT). The normalised impact for each category is thus the actual impact divided by the allocated carrying capacity. 3.3 Validation of model-build up The inventory data on the reference house and the Upcycle house are based on two reports by the Danish Building Research Institute (SBI) published in 2015 and 2013 (SBI, 2015; SBI, 2013). The output results from the GaBi models are compared to the results from these two reports to validate the overall model build- up as well as to give an insight into the magnitude of the deviations an LCA with approximately the same prerequisites has. The inventories for the absolute models are in accordance with the SBI models when comes to material amounts and types, but the system boundaries of the absolute models described in 3.2.2 differ from those set by SBI. The two absolute models are therefor altered to align the prerequisites of respectively the SBI model and the absolute model excluding lifecycle stages etc. to allow for a comparison, see Figure 8 for an illustration of the system boundaries of respectively the SBI models and the absolute models.
  • 29. METHOD       21/74 Production phase Use phase End of life SBI Model Abs. Model SBI Abs. Model SBI Abs. Model Extraction X X Maintenance Demolition (X) Transport X X Repair (X) Transport X Production X X Replacement X X Waste handling X X Construction X Modifications Recycling X X Landconversion X Energy X X Landfill X X Water Land use X Figure 8 Variations in system boundaries of the SBI models and the absolute models Besides the variations in system boundaries, which to the extent possible is adjusted, there are also variations in the database background. The SBI models are based on ESCUO database and the absolute models on the Ecoinvent database. A full description of the differences between the SBI models and the absolute models as well as the alternations made to the absolute model for the validation process can be seen in appendix I. It is though important to notice that the alternations of the two absolute models to fit the SBI prerequisites are only used in the validation process, and does not form the basis for the models in the further process. 3.4 Allocation of carrying capacity The following section will describe the method(s) used to allocate a “fair share” of the environmental carrying capacity to the dwelling. There is though no unequivocal solution to this issue, why the definition of this “fair share” might vary depending on the eyes seeing, and the methods presented here just represent some of the ways this allocation could be carried out. The methods used here all take their basis in the person equivalent carrying capacity identified by Bjørn & Hauschild (2015), see section 2.4. This person equivalent carrying capacity is based on an equal distribution of the world’s capacity, implying that all people in the world have an equal share of the environmental capacity to their disposal.
  • 30.   METHOD   22/74   To identify the person equivalent carrying capacity, Bjørn & Hauschild (2015) divided the total environmental carrying capacity of the world by the total number of people. When assessing one person’s impact related to the person equivalent carrying capacity both direct and indirect impacts should therefore be included. A person affects the environment in a number of different ways - daily-life products and services ranging from food and transportation to the construction and running of their dwelling. Apart from these more direct and obvious impacts, a person also impacts the environment more indirectly by public activities or consumption, and the total impact from one person thus includes both the direct impacts and a share of the world’s public impacts that is not directly linked to individual household consumption. When allocating a share of the world’s carrying capacity, the total capacity is first allocated equally to the entire population, then from one person’s capacity a share can be allocated to household, then again from the household a share can be allocated to housing and then finally only a share of the housing category is actually related to the dwelling. This general approach is the allocation methods used in this study illustrated by Figure 9. Figure 9 General allocation method used to allocate a share of the World’s capacity to the dwelling When the share of one person’s carrying capacity allocated to the dwelling is identified, the carrying capacity for an entire dwelling is found by multiplying this share by the average number of residents in a dwelling. The annual carrying capacity for a dwelling (CCdwe) for a specific impact category (i) is thus calculated as: CCdwe,i = CCPE,i * AHH,i * AHDW,i * Rave Where CCPE is the total person equivalent carrying capacity according to Bjørn et al. (2015), AHH is the share of the person equivalent allocated to the household, AHDW is the share of the household allocated to the dwelling and Rave is the average number of residents per dwelling. The first step in the allocation, from the world’s total carrying capacity to the equivalent carrying capacity of one person, is based on equality, i.e. an equal sized share to each person. The further allocation of the person equivalent to the dwelling could though be based on different approaches. In this study two methods for the allocation of the person equivalent is used; allocation based on economic value and allocation based on “Direct”“Indirect” Public
  • 31. METHOD       23/74 current environmental burden. The allocation by economic value uses the current share that the specific activity or product represents of the GDP as allocation key, where the allocation by environmental pressure uses the current share of the total environmental impacts that the specific activity or product represents. For a discussion of the advantages and disadvantage of the two methods see section 5.1. For the economic allocation the Eurostat statistical bank was used as basis for the inventory data on household consumption. Inventories on the environmental pressures from household consumption are though far more ambiguous, and two main reports have been identified as sufficiently comprehensive to form the basis for the environmental allocation; one from the European Environmental Agency (EEA) and one from the European commission. The output of the reports vary, and the environmental allocation is therefor carried out first based on one and then the other, to identify the influence of definition of environmental pressure. The allocation is thus carried out with three different approaches: A. Economic value based on Eurostat statistics ( (BREEAM, 2015)2015) B. Environmental pressure based on a study by EEA (2013) C. Environmental pressure based on a study European commission (2006) All three base their definition of household categories on the COICOP categories defined by the United Nations Statistics Division (2015). The COICOP definitions will likewise form the basis for the allocation method and is described in Figure 10. The allocation is to the extent possible based on the boundary system described in section 3.2.2 to keep consistency between the allocated carrying capacity and the identified building impacts. Classification of individual consumption by purpose (COICOP) COICOP is a reference classification system developed by United Nations Statistics Division (United Nations, 2015). COICOP divides individual consumption expenditures according to their purpose incurred by households, non-profit institutions serving households and general government. The following 12 categories are relevant to household consumption: CP01 – Food and non-alcoholic beverages CP07 – Transport CP02 – Alcoholic beverages and tobacco CP08 – Communications CP03 – Clothing and footwear CP09 – Recreation and culture CP04 – Housing, water, gas, electricity and other fuels CP10 – Education CP05 – Furnishings, equipment and routine maintenance CP11 – Restaurants and hotels CP06 – Health CP12 – Miscellaneous goods and services Figure 10 Classification of indicidual consumption accordin to United Nations Statistics Division (United Nations, 2015)
  • 32.   METHOD   24/74   3.4.1 A. Economic value When allocating according to economic value the allocation key will be identical for all environmental impact categories. To allocate the carrying capacity to the dwelling, the household consumption’s share of Gross Domestic Product (GDP) is firstly identified, then the distribution of household expenses within the COICOP categories is identified, see Table 5. Table 5 Household expenditure for Europe (Eurostat, 2015) Category Europe (EU-28) Household share of GDP2 57,1% Distribution of household expenses3 CP01 Food and non-alcoholic beverage 13% CP02 Alcoholic beverages, tobacco and narcotics 3,6% CP03 Clothing and footwear 5,2% CP04 Housing, water, electricity, gas and other fuels 24,1% CP05 Furnishing, equipment and routine maintenance 5,6% CP06 Health 3,7% CP07 Transport 13% CP08 Communications 2,6% CP09 Recreation and culture 8,7% CP10 Education 1,1% CP11 Restaurants and hotels 8,5% CP12 Miscellaneous goods and services 10,8% The two categories CP04 and CP05 represent all expenses related to the dwelling, however the categories also include non-related consumption such as electricity to appliances (TV, refrigerators etc.) as well as furnishing etc. See Table 6 for the subcategories of CP04 and CP05, which are related to the dwelling, the table also shows how large the share of a specific subcategory is allocated to the dwelling. Three subcategories need further allocation to deduct the non-relevant expenses namely 04.5.1, 05.1.2 and 05.3.1. All other subcategories listed in Table 6 are assumed to solely represent expenses directly related to life cycle expenses of the building. The repair and maintenance of the building are represented in the // 2 In 2013 3 In 2012
  • 33. METHOD       25/74 subcategories 04.1.1 and 04.2.1 indirectly through the direct and imputed rentals. For an overview of the distribution in all sub-categories see appendix J. Table 6 Subcategories of CP04 and CP05 relevant to the dwelling Category Comments % of category To dwelling CP04 – Housing, water, electricity, gas and other fuels 04.1.1 – Actual rentals paid by tenants For main residence 19,3% 100% 04.2.1 – Imputed rentals of owned occupiers For main residence 51,1% 100% 04.5.1 – Electricity All electricity used 7,1% 29%4 04.5.2 – Gas All gas used 3,9% 100% 04.5.3 – Liquid fuels Domestic heating and lighting oils 1,9% 100% 04.5.4 – Solid fuels Coal, coke, firewood and the like 0,6% 100% 04.5.5 – Heat energy District heating, incl. hire of meters etc. 1,4% 100% Total of category to dwelling 80,1% CP05 – Furnishings, household equipment and routine household maintenance 05.1.2 – Carpets and other floor coverings Loose carpets, fitted carpets, linoleum and the like. 5,4% 40%5 05.3.1 – Major household appliances Air conditioners, space- and water heaters, refrigerators, freezers etc. 10,1% 40%6 Total of category to dwelling 6,2% Based on the economic allocation the share of the person equvivalent capacity in all impact categories allocated to the dwelling is thus: Aeco = 57% * (24,1%*80,1% + 5,6%*6,2%) = 11,2% // 4 Share of a household’s electricity consumption related to building operation (SBI, 2008) 5 Share from appliances related to building operation (e.g. space- and water heater) is assumed to be 40% 6 Share related to solid flooring (e.g. wood flooring) is assumued to be 40%
  • 34.   METHOD   26/74   Table 7 Allocation of carrying capacity to respectively the entire household and to the building. For all impact categories. Europe (EU-28) To household [% of total] 57,1% To dwelling [% of household] 19,7% To dwelling [% of total] 11,2% 3.4.2 Allocation by current environmental pressure (B+C) The following section will try to identify the share of carrying capacity that can be allocated to the dwelling, if the allocation is based on the dwelling’s current environmental impacts. The allocated share in an impact category will thus corresponds to the dwelling’s percentage wise current impact in that category. For instance if assumed the dwelling represents 20% of the total climate change impact from the household, then 20% of the climate change capacity is allocated to the dwelling. To allocate according to the environmental pressure from a building in relation to other products and services is more comprehensive than to identify and allocate according to the economic value it represents. The current section is based on two primary studies in this field, namely the report Environmental pressure from European consumption and production from the EEA (2013) and Environmental Impacts of products (EIPRO) and associated appendices by the European Commission Joint research centre (2006), see Figure 11 for further description. The approach in the studies varies, and the environmental pressures found for different categories are not identical. To identify if one study over the other would be more applicable in the current allocation scenario would require a comprehensive knowledge and insight into the two studies. The following allocation is carried out twice first based on the one method and then the other. According to a Swiss study by the Federal Office for the Environment (FOEN, 2011) the direct emissions in CO2 equivalents from Swiss households covers 39% of the total CO2 equivalents emitted by Switzerland. In the current study this relation between household emissions and total emissions is assumed identical when indirect emissions are accounted for. Further more Switzerland is assumed representative for the European relation between household and total emissions, why 39% of the person equivalent carrying capacity allocates to the private household. This allocation to household will be applied to all impact categories for both the allocation according to the EEA report as well as the EIPRO report.
  • 35. METHOD       27/74 B. European Environmental Agency (EEA) C. European Comission (EIPRO) Title: Environmental pressure from European consumption and production Published: 2013 Title: Environmental impact of produts (EIPRO) Published: 2006 Description: The study identifies the hotspots and leverage points in European consumption and production. The study uses an environmentally extended input- out put analysis, and in the consumption perspective this includes all environmental pressures caused directly or indirectly by national consumption. The study focuses on environmental pressure caused by air emissions and material flows, based on data from Eurostat. The environmental impacts are identified as: • Emissions of GHG • Acidifying emissions • Emissions of Tropospheric ozone forming precursors • Material flow Description: The study identifies the products having the greatest environmental impact throughout the life cycle. For this purpose a new input-output model was developed, covering the environmental impact of all products consumed in EU-25 (produced and imported), including the life cycle stages of extraction, transport, production, use and waste management. The environmental impacts are identified as: • Abiotic depletion • Acidification • Ecotoxicity • Global warming • Eutrophication • Human toxicity • Ozone layer depletion • Photochemical oxidation Figure 11 Description of the two environmental studies forming the basis for the two allocation scenarios according to environmental pressure (EEA, 2013; European Commission, 2006) 3.4.3 Allocation based on EEA (B) The study from the EEA (2010) identified the environmental pressure from the average European (EU-28) household consumption based on the COICOP categories, see Figure 10 for description of the COICOP categories. The environmental pressure has been identified in four impact categories; Greenhouse gas emissions, acidifying emissions, tropospheric ozone precursors and material use. Based on these four categories a category averaging the four has been created, which will be applied to the impact categories of Bjørn et al. (2015) that is not covered by the initial four, see Table 8 for the distribution in all five categories.
  • 36.   METHOD   28/74   Table 8 Relative impact of the COICOP main categories in the five impact categories (EEA, 2013) GHG emissions Acidifying emissions Trophosperic ozone precursor Material use Average The environmental pressure from the different COICOP categories is seen to vary from impact category to impact category, see Table 8. The impact from CP04 Housing, water, electricity, gas and other fuels is for example seen to vary from 14% of household impact from acidifying emissions to 36% from greenhouse gas emissions. 17%   36%   11%   24%   4%   43%   14%   9%   22%   6%   17%   25%   11%   38%   3%   34%   27%   14%   12%   6%   28%   26%  11%   24%   5%  
  • 37. METHOD       29/74 Table 9 Application of impact categories from EEA (2013) to impact categories from Bjørn & Hauschild (2015). The “Average” category is an average of the four EEA cateogires, and applied when no EEA cateogry is defined. Application of impact categories from EEA (2013) to those from Bjørn & Hauschild (2015) EEA category Bjørn & Hauschild category Acidification è Terrestrial acidification Average è Terrestrial eutrophication Material use è Water depletion Material use è Land use, soil erosion Material use è Land use, biodiversity Global warming è Climate change Average è Ozone depletion Average è Freshwater eutrophication Average è Marine eutrophication Tropospheric ozone precursors è Photochemical ozone formation Average è Freshwater ecotoxicity As previous the categories CP04 and CP05 are further allocated, since not all impacts included is related to the dwelling (i.e. furnishing, household equipment etc.). Due to lack of information on the distribution of environmental pressure of the subcategories in the report, the allocation from the COICOP main categories (CP04 and CP05) to the subcategories (CP04.1.1, CP04.2.1 etc) is based on the economic distribution identified in the previous section, see Table 6 and not on environmental pressure. The study from Bjørn & Hauschild (2015) identifies the carrying capacity in 11 impact categories but the study from EEA (2013) only identifies the distribution of environmental burden in five categories (including the average). The allocation of the carrying capacity is carried out according to the EEA impact category found the most appropriate, see Table 9, i.e. Terrestrial eutrophication is allocated according to the environmental impact from the Average category and Water depletion according to material use. The final allocation of carrying capacity to the building in the 11 impact categories is seen to vary from 4,6% in Terrestrial acidification to 11,5% in Climate change, see Table 10.
  • 38.   METHOD   30/74   Table 10 Allocation of carrying capacity based on current environmental pressure. Where environmental pressure is defined according to European Environmental Agency (2013) Europe (EU-28) Household [% of total] 39% Dwelling [% of total] Terrestrial acidification 4,6% Terrestrial eutrophication 8,2% Water depletion 8,8% Land use, soil erosion 8,8% Land use, biodiversity 8,8% Climate change 11,5% Ozone depletion 8,2% Freshwater eutrophication 8,2% Marine eutrophication 8,2% Photochemical ozone formation 8,1% Freshwater ecotoxicity 8,2% 3.4.4 Allocation based on EIPRO (C) The EIPRO study from the European commission (2006) is a bit older than the EEA study (2013), but it’s a comprehensive study including a comparative analysis of method and findings in other relevant studies. The EIPRO study identifies the environmental pressure in eight impact categories, from which seven of them are relevant in the current study. The EIPRO study takes its basis in the general COICOP definitions as the EEA study, but in contrast to the EEA study, EIPRO actively consider the content of the categories and moves impact from one category to another. For instance the household electricity is in the COICOP definitions all gathered in the subcategory CP04.05 Electricity, gas and fuels (in CP04), but the EIPRO study couples the electricity consumption with relevant activity, so i.e. electricity for cooking is accounted for in the Food category.
  • 39. METHOD       31/74 Table 11 Relative impact of the COICOP main categories in the seven impact categories (European Commission, 2006) Global warming Acidification Photochemical oxidation Abiotic depletion Eutrophication Ecotoxicity Ozone layer depletion 31%   24%   18%   6%   9%   5%   31%   2%   26%   14%   7%   10%   6%   27%   3%   22%   20%   7%   9%   7%   22%   35%   20%   5%   7%   5%   60%   4%   10%   6%   3%   13%   34%   6%   20%   15%   7%   9%   6%   25%   3%   21%   4%   14%   11%   9%   10%  
  • 40.   METHOD   32/74   The environmental pressure from the joint category CP04-05 Housing, furniture etc. is seen to vary from 35% of the total household impact from acidification to only 10% from eutrophication. The allocation key in the different categories is applied to the 11 categories from Bjørn & Hauschild (2015) according to Figure 12. In the EIPRO study the content of the subcategories is defined for only four of the seven impact categories; Acidification, Eutrophication, Global warming and Photochemical oxidation. An average category is therefore created, and the application of the subcategories to the main categories is also seen from Figure 12. Application of impact categories from the European Commission (2006) to those from Bjørn & Hauschild (2015) Bjørn & Hauschild EIPRO Main category Subcategory Terrestrial acidification è Acidification è Acidification Terrestrial eutrophication è Eutrophication è Eutrophication Water depletion è Abiotic depletion è Average Land use, soil erosion è Abiotic depletion è Average Land use, biodiversity è Abiotic depletion è Average Climate change è Global warming è Global warming Ozone depletion è Ozone layer depletion è Average Freshwater eutrophication è Eutrophication è Eutrophication Marine eutrophication è Eutrophication è Eutrophication Photochemical ozone formation è Photochemical oxidation è Photochemical oxidation Freshwater ecotoxicity è Ecotoxicity è Average Figure 12 Application of impact categories from the European Comission (2006) to impact categories from Bjørn & Hauschild (2015). The “average” category is an average of the four subcategories and is applied to the main cateogires when no subcategory distribution were stated in EIPRO. As previously described the EIPRO study has not strictly kept to the definitions of the subcategories. From Table 12 the subcategories relevant to the building in the impact category Global warming is shown together with information on their share of the category. For all sub-cateogires and the distribution of environmental pressure in the four impact categories see appendix K.
  • 41. METHOD       33/74 Table 12 Distribution of subcategories for Global waming CP04 +CP05 Housing etc. % of category Alloc. To building A257 (Heating with) heating equipment, except electric and warm air 19,9% 100% A31 New residential 1unit structure, nonfarm 13,6% 100% A33 New additions and alterations, nonfarm, construction 7,6% 100% A42 Maintenance and repair of farm and nonfarm residential structure 3,0% 100% A149 Partitions and fixtures, except wood 1,3% 100% A334 (use of) electric housewares and fans 0,8% 100% A25 Crude petroleum and natural gas 0,8% 100% Total of category to dwelling 47% Based on the allocation of the environmental impact to the main categories of housing, and then again to the subcategories relevant to the dwelling the final share of the carrying capacity in the 11 impact categories is identified, see Table 13. The allocation share is seen to vary from only 1,3% in Eutrophication (marine, freshwater and terrestrial) to 5,6% abiotic depletions such as water and land use. Table 13 Allocation of carrying capacity in the 11 impact categories from Bjørn & Hauschild (2015) based on the EIPRO study (European Commission, 2006) Europe (EU-28) Household [% of total] 39% Dwelling [% of total] Terrestrial acidification 3,4% Terrestrial eutrophication 1,3% Water depletion 5,6% Land use, soil erosion 5,6% Land use, biodiversity 5,6% Climate change 4,3% Ozone depletion 3,3%
  • 42.   METHOD   34/74   Freshwater eutrophication 1,3% Marine eutrophication 1,3% Photochemical ozone formation 4,3% Freshwater ecotoxicity 3,3% 3.4.5 Resume of findings The three allocation scenarios have led to three suggestions for the share of the person equivalent carrying capacity that could be allocated to the dwelling, see Table 14. The allocation according to economic value (A) is in all impact categories except GWP seen to allocate a greater share of the carrying capacity to the dwelling than the other two scenarios (B+C). In general it is seen that scenario C allocates least of the carrying capacity to the dwelling in all impact categories. Table 14 Allocation of the total carrying capacity to the dwelling based on three approaches A, B and C. CC = carrying capacity. All figures of carrying capacity are in person equivalent. A. Economic B. Emission EEA C. Emission EIPRO Terrestrial acidification 11,2% 4,6% 3,4% Terrestrial eutrophication 11,2% 8,2% 1,3% Water depletion 11,2% 8,8% 5,6% Land use, soil erosion 11,2% 8,8% 5,6% Land use, biodiversity 11,2% 8,8% 5,6% Climate change 11,2% 11,5% 4,3% Ozone depletion 11,2% 8,2% 3,3% Freshwater eutrophication 11,2% 8,2% 1,3% Marine eutrophication 11,2% 8,2% 1,3% Photochemical ozone formation 11,2% 8,1% 4,3% Freshwater exotoxicity 11,2% 8,2% 3,3% The economic allocation method (A) is chosen to form the basis of the following analyses. None of the methods is though more correct than the others, the economic allocation is used solemnly due to it being the more generally accepted and used allocation method.
  • 43. METHOD       35/74 3.5 Sensitivity analysis The determination of the environmental carrying capacity as well as the determination of the total environmental impacts from the building is subjects to uncertainties. A sensitivity analysis is carried out in order to identify the effects of deviations in both the carrying capacity and the building impacts determination. The sensitivity analysis is carried out on the Standard house based on the three scenarios illustrated in Table 15, and where scenario 1 is based on the current calculations of both carrying capacity and building impacts. Table 15 Specification of the scenarios deviation from the impacts and capacity asumptions used as analyses basis Carrying capacity Building impacts Scenario 1 - - Scenario 2 -15% +15% Scenario 3 +15% -15%
  • 45. RESULTS       37/74 4 RESULTS In the following section the results from the analyses is displayed and shortly described. In the analyses it was found that the impact on Land use – erosion was immensely transgressed in all cases. For the standard house for instance the impact in this category was seen to exploit 9.989.527% of the carrying capacity. The land use characterization factors contain great assumptions, and great variations in the results were expected. However due to the immense variations, the impact category have been excluded from the result display and further analyses, since the methodology is assumed in the need of further improvement before applied in the absolute sustainability assessment. 4.1 Carrying capacity for a single-family house The average number of residents per single-family houses in Denmark is 2,6 persons (Statistic Denmark, 2015). Based on this number the carrying capacity of a single-familty house is shown in Table 16. Table 16 Carrying capactiy (allocated according to economic value) per dwelling when the average number of residents is 2,6. Annual carrying capacity per single-family house – 2,6 person per dwelling Terrestrial acidification (AP) 670 mole H+ eq. Water depletion 89 m3 Land Use Erosion 0,52 ton eroded soil Biodiversity 4369 m2 *year Climate change (GWP) (Temperature) 287 kg CO2 eq. (Radiative forcing) 152 kg CO2 eq. Ozone depletion (ODP) 0,02 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,13 kg P eq. Marine 9 kg N eq. Terrestrial 815 mole N eq. Photochemical oxidant formation (POCP) 14 kg NMVOC Freshwater ecotoxicity 2912 PAF*m3 *day
  • 46.   RESULTS   38/74   4.2 Current environmental pressure from dwellings In the following the impacts from current building practice related to the carrying capacity are presented based on the two reference buildings, namely the Standard house representing current prevalent construction methods and the Upcycle house representing one of the extremes when come to reducing environmental impact from material use. 4.2.1 Standard house (128m2 ) From Table 17 the resulting impact per year from the standard house is shown both including and excluding the impact from the operational energy in the buildings use phase. Table 17 Standard house (128m2 ) annual impacts including (incl) or excluding (excl) use phase energy. Building lifetime 50 years Annual impacts, Standard house – 128m2 , building lifetime 50 year Incl. Excl. Terrestrial acidification (AP) 178 83 mole H+ eq. Water depletion 66 23 m3 Land Use Erosion 52370 920 ton eroded soil Biodiversity 1055 357 m2 *year Climate change (GWP) 2376 1047 kg CO2 eq. Ozone depletion (ODP) 0,0002 0,0001 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,70 0,22 kg P eq. Marine 0,58 1 kg N eq. Terrestrial 90 41 mole N eq. Photochemical oxidant formation (POCP) 8 3 kg NMVOC Freshwater ecotoxicity 2723 1206 PAF*m3 *day The resulting impacts from the standard house shown in Table 17 are then related to the carrying capacity derived in section 4.1 to illustrate the percentage of the carrying capacity depleted by the house, which is here referred to as an absolute sustainability assessment, see Figure 13.
  • 47. RESULTS       39/74 Absolut sustainability assessment - Standard house (Incl. use phase energy) - IN,B Acidification, terrestrial 27% Water depletion 74% Land use Erosion - Biodiv. 24% Climate change Temp. 828% Rad. Forc. 1563% Ozone depletion 0,7% Eutrophication Freshwater 524% Marine 6% Terrestrial 11% Ozone formation 57% Freshwater ecotoxicity 94% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area. LEK2015 Figure 13 Absolute sustainability assessment of the standard house including use phase energy From the absolute sustainability assessment illustrated in Figure 13 it seems evident how impacts from the standard house exceeds the carrying capacity with immense lengths in terms of both freshwater eutrophication and climate change. The freshwater eutrophication on 0,7 kg P eq. exceeds the capacity by more than a factor 4 demanding a reduction of more than 80% to stay within the carrying capacity. The climate change impact amounting to 2376 kg CO2 eq. is exceeding the capacity by a factor of 15. The reduction on climate change impact is thus seen call for a reduction up to 94%. In addition to the two impact categories were the capacity has already been transgressed additional two categories are seen near to the boundaries. The freshwater exotoxicity of 2723 PAF*m3 *day is seen to exploit 94% of the capacity together with the water depletion of 66m3 which is exploit 74% of the capacity. If the impacts are grouped according to life cycle stages, the use phase is seen to represent more than 50% in all impact categories except for the two land use categories, see Figure 14. When it comes to climate change the use phase is seen to represent almost 60%, and from which the 56% comes from energy consumption for operating the building and the rest from replacements and repair.
  • 48.   RESULTS   40/74   This indicates that nearly 44% of the impact is derived from material use and construction of the building. From Figure 15 it shows how the roof, the outer walls and the ground slab contributes significantly to the resulting impact, but also Doors and windows are seen to contribute considerably. Important to notice is also the impact from energy used for constructing the building, which is not insignificantly. On i.e. GWP it contributes with more than 10% of the impact. -­‐20%   0%   20%   40%   60%   80%   100%   Production   Construction   Use  phase   EoL   Site   Figure 14 GWP contribution from life cycle stages (incl. site occupation and transformation) for the Standard house. Over a 50year period. 0%   10%   20%   30%   40%   50%   60%   70%   80%   90%   100%   Doors  and  windows   Floors  and  surfaces   Foundation   Ground  slab   Inner  walls     Installations   Outer  walls   Roof   Const.  Energy   Figure 15 GWP impact distribution from the standard house over a 50 year period excluding use phase energy and impacts related to the site.
  • 49. RESULTS       41/74 4.2.2 Upcycle house The heated area of the Upcycle house is not as big as the area of the standard house. The size of a building is naturally of great importance to the resulting environmental impacts, and the more square meters the bigger resulting impact. Therefore the environmental impact of the Upcycle house is presented both in its original size (104m2 ) but also in a size corresponding to the size of the standard house (128m2 ). Both houses are expected to house an equal size family, and the fewer square meters of the Upcycle house is therefor considered to be a result of an improved functionality of the house. The better utilization of the built area is credited when presenting the resulting impact according to the original size, where the presentation of the impact when the size is equal to the standard house allows for a direct comparison of the upcycled building style vs. the more common. 4.2.2.1 Original building area (104m2 ) From Table 18 the resulting impacts per year from the Upcycle house with the original size of 104m2 are shown both including and excluding the impact from the operational energy in the buildings use phase. Table 18 Upcycle house (104m2 ) impact per year including (incl) or excluding (excl) use phase energy . Building lifetime 50years Annual impact from the Upcycle house – 104m2 , building lifetime 50 year Incl. Excl. Terrestrial acidification (AP) 124 48 mole H+ eq. Water depletion 44 9 m3 Land Use Erosion 42113 311 ton eroded soil Biodiversity 743 175 m2 *year Climate change (GWP) 1373 293 kg CO2 eq. Ozone depletion (ODP) 0,0001 0,00003 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,5 0,1 kg P eq. Marine 0,4 0,1 kg N eq. Terrestrial 60 21 mole N eq. Photochemical oxidant formation (POCP) 5 2 kg NMVOC Freshwater ecotoxicity 2053 821 PAF*m3 *day As in the previous case the absolute sustainability assessment is also applied to the impacts from the Upcycle house, which appears in Figure 16.
  • 50.   RESULTS   42/74   Absolute sustainability assessment - Upcycle house (including use phase energy) - IN,B Acidification, terrestrial 19% Water depletion 50% Land use Erosion - Biodiv. 17% Climate change Temp. 479% Rad. Forc. 903% Ozone depletion 0,4 Eutrophication Freshwater 369% Marine 4% Terrestrial 7% Ozone formation 38% Freshwater ecotoxicity 70% Comments: All impacts included. Building lifetime, 50 years. 104m2 heated area. LEK2015 Figure 16 Absolute sustainability asessment of the upcycle house (104m2 ) including usephase energy From Figure 16 it shows how the impacts from the Upcycle house also transgress the boundaries of the carrying capacity with immense lengths both for freshwater eutrophication and climate change. The yearly impact on freshwater eutrophication on 0,5 kg P eq. exceeds the carrying capacity by nearly a factor 3, requiring a further reduction on 74%. Climate change on the other hand is impacted yearly with 1373 kg CO2 eq. from the Upcycle house, which exceeds the carrying capacity by a factor. The need for reduction would then correspondingly be 89%. Apart from the transgression of Climate change and freshwater eutrophication only freshwater ecotoxicity is seen approaching the boundary with an impact corresponding to 70% of the carrying capacity. The resulting impacts are reduced from the Upcycle house because of the use of upcycled materials leading the constant use phase energy to represent a larger share of the summarised impacts, see Figure 17.
  • 51. RESULTS       43/74 When it comes to the use phase energy, the impact on GWP is 1080 kg CO2 eq. per year out of the total GWP impact of 1373 kg CO2 eq.. The use phase energy is thus seen representing 79% of the total impact, where on the Standard house the use phase energy only represented 56% of the total impact. -­‐20%   0%   20%   40%   60%   80%   100%   Production   Construction   Use  phase   EoL   Site   Figure 17 GWP contribution from life cycle stages (including site occupation and transformation) for the Upcycle house. Over a 50 year period. -­‐20%   0%   20%   40%   60%   80%   100%   Doors  and  windows   Floors  and  surfaces   Foundation   Ground  slab   Inner  walls     Installations   Outer  walls   Roof   Terrace  and  greenhouse   Const.  Energy   Figure 18 Impact distribution from the Upcycle house over a 50 year period excluding use phase energy and impacts related to the site.
  • 52.   RESULTS   44/74   From Figure 18 it shows how impact from energy for construction of the house plays a more significant role in the Upcycle house than what was the case with the Standard house. The construction energy alone is seen to represent around 35% of the total impact on climate change as well as water depletion, and around 25% of the total when it comes to freshwater eutrophication. The impacts from installations are seen to increase compared to the standard house, which is due the general decrease in the impact from material and construction on the Upcycle house. 4.2.2.2 Building area equal to the standard house If the size of the Upcycle house instead is increased to 128m2 equal to that of the Standard house, allowing for a more direct comparison of the advances of the upcycled materials, the resulting annual impact of the building are illustrated in Table 19. Table 19 Upcycle house (128m2 ) impact per year including (incl) or excluding (excl) use phase energy . Building lifetime 50years Annual impact from the Upcycle house – 128m2 , building lifetime 50 year Incl. Excl. Terrestrial acidification (AP) 153 59 mole H+ eq. Water depletion 54 11 m3 Land Use Erosion 51831 382 ton eroded soil Biodiversity 914 216 m2 *year Climate change (GWP) 1690 361 kg CO2 eq. Ozone depletion (ODP) 0,0001 0,00003 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,6 0,1 kg P eq. Marine 0,5 0,1 kg N eq. Terrestrial 74 25 mole N eq. Photochemical oxidant formation (POCP) 6,4 2 kg NMVOC Freshwater ecotoxicity 2527 1010 PAF*m3 *day
  • 53. RESULTS       45/74 Absolute sustainability assessment - Upcycle house (all) - IN,B Acidification, terrestrial 23% Water depletion 61% Land use Erosion - Biodiv. 21% Climate change Temp. 589% Rad. Forc. 1111% Ozone depletion 0,5 Eutrophication Freshwater 454% Marine 5% Terrestrial 9% Ozone formation 47% Freshwater ecotoxicity 87% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area Figure 19 Absolute sustainability asessment of the Upcycle house (128m2 ) including use phase energy The additional 24m2 added to the Upcycle house to make it comparable to the Standard house are seen to contribute with an additional 317 kg CO2 eq. per year as well as an extra 0,1 kg P. eq. when considering the two categories already exceeding the carrying capacity. This gives a total transgression of the climate change category by a factor 5 to 10 requiring a reduction of 83% to 91% depending on the capacity definition. On the freshwater eutrophication the transgressions is seen to be around a factor 4 requiring a decrease of an extra 78% to reach below the capacity. The impacts from the Upcycle house correspond to a decrease of 29% on GWP when compared to the impact from the standard house. When it comes to the freshwater eutrophication the impact corresponds to a 14% reduction. The reduction in GWP and freshwater eutrophication are seen to not just contribute to an increased impact in the remaining categories, implying that the reductions are not at the expense of a burden shift.
  • 54.   RESULTS   46/74   4.3 Use phase energy In the following the effects of decreased energy consumption in the use phase is illustrated. 4.3.1 Standard house When the energy consumption is decreased from LEK2015 to BK 2020 the transgression of the climate change boundary is seen reduced with around 25% and the transgression of the freshwater eutrophication with around 30%. The transgression is though still seen to be 1052% for climate change and 354% for freshwater eutrophication. Even if the use phase energy is zero, implying that the building has no energy consumption throughout the lifetime, the transgression is still immense 589% on climate change and 63% on freshwater eutrophication. The use phase energy is seen to contribute with 56% of the total climate change impact when energy class LEK2015 is used, and around 40% when using energy class BK2020. Absolute sustainability assessment - Standard house (various energy consumption) - IN,B Br 2015 Br 2020 None Terrestrial acidifiation 27% 20% 12% Water depletion 74% 51% 26% Land use Erosion - - - Biodiv. 24% 24% 8% Climate change Temp. 828% 610% 365% Rad. for. 1563 % 1152 % 689% Ozone depletion 0,7% 0,6% 0,4% Eutrophi- cation Freshwat. 524% 354% 163% Marine 6% 4% 11% Terrest. 11% 8% 5% Ozone formation 57% 42% 24% Freshwater ecotoxicity 94% 69% 41% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area LEK2015 BK2020 No Use phase energy Figure 20 Absolute sustainability asessment of the Standard house (128m2 ) with various energy consumption
  • 55. RESULTS       47/74 4.3.2 Upcycle house For the Upcycle house the change from energy class LEK2015 to BK2020 is seen to reduce the climate change impact with 37%, though still with a transgression of the carrying capacity of 271-601%. On the freshwater eutrophication the reduction is also 37%, but with a transgression of 184% when the energy consumption is reduced to BK2020. When the use phase energy is assumed non-existent the impact on climate change is still seen to exceed the carrying capacity, but now with only 26-137%, and freshwater eutrophication is seen to stay just within the carrying capacity. The use phase energy is seen to constitute with 79% of the climate change impact when the energy class is LEK2015, but 66% when the energy class is BK2020. Absolute sustainability assessment - Upcycle house (various energy consumption) - IN,B Br 2015 Br 2020 None Terrestrial acidifiation 23% 16% 12% Water depletion 61% 38% 13% Land use Erosion - - - Biodiv. 21% 20% 5% Climate change Temp. 589% 371% 126% Rad. for. 1111 % 701% 237% Ozone depletion 0,5% 0,3% 0,1% Eutrophi- cation Freshwat. 454% 284% 93% Marine 5% 3% 1% Terrest. 9% 6% 3% Ozone formation 47% 31% 14% Freshwater ecotoxicity 87% 62% 35% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated a Energy consumption according to the Danish building regulations class 2015 and 2020, and excluding use phase energy. LEK2015 BK2020 No use phase energy Figure 21 Absolute sustainability asessment of the Upcycle house (128m2 ) with various energy consumption
  • 56.   RESULTS   48/74   4.4 Building lifetime To identify the effect of an increased lifetime the LCA on both Standard house and Upcycle house have been carried out with a building lifetime of respectively 50 years and 120 years. With the increased lifetime of 120 years any potential modifications of the buildings have not been accounted for. The prolonged lifetime will only affect the impact from materials, and use phase energy is therefore not included in the following. For the following parametric variations, only key findings are summarized. For a full result display see appendix G. 4.4.1 Standard house When looking at the impact from materials and construction Table 20 shows how the prolonged lifetime from 50 to 120 years decreases the yearly impact on climate change by 43%. When looking at freshwater eutrophication the yearly decrease is seen to be 33%. Table 20 Yearly mpact from material and construction in the Standard house normalised according to carrying capacity, with a building lifetime of 50 or 120 years. 50 year lifetime 120 year lifetime Climate change Temperature 365% 207% Radiative forcing 690% 391% Freshwater eutrophication 163% 109% Se appendix G for a full result display. 4.4.2 Upcycle house When looking at the Upcycle house the prolonged lifetime is seen to affect the yearly impact on climate change by a reduction of 40%. For the freshwater eutrophication the decrease is seen to be around 30%. Table 21 Yearly mpact from material and construction in the Upcycle house normalised according to carrying capacity, with a building lifetime of 50 or 120 years. 50 year lifetime 120 year lifetime Climate change Temperature 126% 76% Radiative forcing 237% 143% Freshwater eutrophication 93% 67% Se appendix G for a full result display.
  • 57. RESULTS       49/74 4.5 Validation of model build-up It is important to note that the resulting impacts from the project models displayed in this section are not representative for the absolute impact of the buildings used in the project, since the project models for this section have been alternate to represent the same methodological approach as used by the SBI to create a basis of comparison. 4.5.1 Standard house From Table 22 the resulting impacts in the five categories; global warming potential (GWP), ozone depletion (ODP), photochemical ozone creation (POCP), acidification (AP) and eutrophication (EP) are shown. The deviation regarding the GWP is +15%, but when it comes to the remaining four impact categories, the deviations are seen to be remarkable higher. The deviations in the remaining four impact categories are ranging between +75% for AP up to +388% for EP. Table 22 Resulting impacts for a 120 year period of the Reference house according to SBI and the current project model, when prerequisites are approximately the same SBI Model Deviation GWP [kg CO2eq] 55.200 63.492 +15% ODP [kg R-11eq] 0,002 0,0058 +190% POCP [kg Ethene eq.] 20,8 41,7 +100% AP [kg SO2eq] 236 409 +74% EP [kg PO4eq] 26,1 101 +388% From Figure 22 the relative impact in the different categories is illustrated for the SBI model, and in Figure 23 for the current project model.
  • 58.   RESULTS   50/74   Reference house – SBI 120 year period Reference house – Model 120 year period k From Figure 22 and Figure 23 the impact distribution between the building parts in the two models is seen fairly alike. There are though some differences, which is partly due to differences in the grouping of construction parts. The category “Floors and surfaces” in the altered absolute project model does not exist in the SBI-model, but assumed mainly to be included in the “Inner walls “category in the SBI model. Further more there are deviations when it comes to windows and doors, which in the absolute model is group in one category, but in the SBI model the category only includes windows, and doors would thus be included in an other category in the SBi model, ie. “inner walls” or “outer walls”. There are though some variations seen in ie. Groundslabs impact in POCP as well as the installations impact in AP and EP. 4.5.2 Upcycle house Since only the GWP is quantified in the SBI report (SBI, 2013) dealing with the Upcycle house this is the only impact category the Upcycle house will be validated according to. From Table 23 shows how the resulting GWP of the model is 100% higher than the impact from the SBI analyses. Table 23 Resulting GWP over a 50 year period for the Upcycle house according to SBI and the current model, based on equal prerequisites SBI Model Deviation GWP total [kgCO2eq/m2 /yr] 0,7 1,4 +100% To create a clearer picture of the reason for the large deviation the resulting GWP is identified for the individual construction parts, see Figure 22 Contribution of the construction parts of the SBI model (SBI, 2015) Figure 23 Contribution of construction parts of the project model Installations Windows Inner walls Roof Outer walls Ground slab Columns and beams Foundations
  • 59. RESULTS       51/74 Graph 1. The figure shows, how the greatest relative deviations is seen on the Inner surfaces, the roof and the inner walls. Common for these three construction parts is that they are all primarily constituted by timber based products such as OSB, paperwool and structural timber. For the inner surfaces timber based products constitutes 60% of the mass, for the inner walls it is 54% of the mass and for the roof it constitutes a total of 73%. Graph 1 GWP displayed on construction parts for respectively the project model and the SBI model 4.6 Sensitivity analysis From Figure 24 the effects of a deviation on +/- 15% on the carrying capacity combined with a deviation of +/- 15% on the building impacts is illustrated. Scenario 2 increases the climate change pressure from a factor 15 transgression of the capacity to a factor 20, as well as the freshwater eutrophication from a transgression of the capacity of a factor 4 to a transgression of a factor 6. Further more water depletion and freshwater ecotoxicity is pushed over the line and scenario 3 thus causes an exploitation of 100% of the water capacity and a 27% transgression of the freshwater ecotoxicity capacity. From scenario 3 the transgression on the climate change capacity is seen decreasing from a factor 15 to a factor 10, and the transgression of freshwater eutrophication is seen decreased from a factor 4 to a factor 3. The water depletion is seen decreasing from an exploitation of 74% of the capacity to 55% of the capacity, and the pressure on freshwater ecotoxicity is seen decreasing from an exploitation of 94% of the capacity to 69%. -­‐4000   -­‐2000   0   2000   4000   6000   8000   10000   [kgCO2]   GWP  of  120-­‐year  period   Model   SBI  
  • 60.   RESULTS   52/74   Absolute sustainability assessment - Sensitivity analysis, Standard house - I/C Sc.1 Sc2 Sc3 Terrestrial acidifiation 27% 36% 20% Water depletion 74% 100% 55% Land use Erosion - - - Biodiv. 24% 33% 18% Climate change Temp. 828% 1120 % 612% Rad. for. 1563 % 2114 % 1155 % Ozone depletion 0,7% 0,9% 0,5% Eutrophi- cation Freshwat. 524% 710% 388% Marine 6% 9% 5% Terrest. 11% 15% 8% Ozone formation 57% 77% 42% Freshwater ecotoxicity 94% 127% 69% Comments: All impacts included. Building lifetime, 50 years. 128m2 heated area I/C = Impact relative to carrying capacity Scenario 1: Carrying capacity and building impacts identical to the general analysis Scenario 2: -15 carrying capacity and +15% building impacts Scenario 3: +15% carrying capacity and -15% building impacts Scenario 2 Scenario 1 (basis) Scenario 3 Figure 24 Sensitivity analsysis illustrating the effects of a +/- 15% change in carrying capcity calculation and +/- 15% in building impact assessment
  • 61. DISCUSSION       53/74 5 DISCUSSION 5.1 Allocation of the carrying capacity The definition of the share that should be allocated from the total carrying capacity to the building would probably differ depending on the eyes seeing. People engaged in the construction industry would most likely find it bigger than people engaged in other industries, and again policymakers, financiers, sociologist and so on might have different views on what this “fair share” looks like. A clear and definite answer to the definition of this “fair share” allocated to the building might therefor be non-existent, and the approaches used in this study are just some of many possible. Three approaches to the allocation of the carrying capacity were used in the study, with all three initially based on the person equivalent carrying capacity identified for the World by Bjørn & Hauschild (2015). One approach allocated the person equivalent carrying capacity by economic value and two allocated it by current environmental pressure. The allocation by economic value assigned an equal share of all impact categories to the building based on its economic share of a person’s household economy, where the allocation based on environmental impact varied from impact category to impact category. The economic allocation is somewhat more straightforward than the allocation based on environmental pressure. The inventories on household economy are comprehensive and available in national or international statistical databanks such as Eurostat or Statistic Denmark. An identification of the buildings economic part of the household economy is therefor relatively forthright. The economic allocation though assigns an equal share of the carrying capacity to all impact categories, regardless of the fact that some products and services would have a natural diversity in environmental pressure from impact category to impact category. Agriculture would for instance tend to have a relatively larger impact on the nitrogen- and phosphors cycles than what would be expected from the building industries. It could therefore be wise to assign a larger share of the carrying capacity to the agricultural industry than to the building industry even if assumed representing the same economic value. When on the other hand allocating according to the current environmental pressure the process of identifying the buildings share of the household’s impact is more complex. The environmental pressures from the ng household consumption is not as unequivocal identified as for the economic value, and for that reason the allocation method have been carried out based on two scientific reports with diverse output results. When
  • 62.   DISCUSSION   54/74   dealing with environmental pressures the boundaries becomes more blurred and one study might include indirect effects that another study ignores, and identifying if one background report is more accurate than the other requires a comprehensive knowledge an insight into the studies. Another downside to the allocation based on current pressures is the fact that the allocation method can tend to punish industries, services etc. that have already reduced their impact immense. These industries or services will have a smaller share of the capacity allocated than for industries or services with a currently high environmental pressure. When looking at the carrying capacity allocated to the building in the impact category climate change the three allocation methods resulted in an allocation of 11,2% when using the economic allocation and an allocation of 11,5% respectively 4,3% when using the current environmental pressure based on EEA and EIPRO. The impact category where the variation in allocated share differs the most, when comparing allocation method, is the eutrophication categories. The share is seen varying from 1,3% when allocating according to environmental pressure based on EIPRO reaching 11,2% when based on the economic allocation. All three methods used are though based on the person equivalent carrying capacity implying that an equal share of the world’s capacity is initially allocated to each citizen of the world implying a fundamental equal distribution of the world’s resources. One could argue that a fully economic or environmental allocation would be more accurate, implying that for example a fully economic allocation of the world’s capacity is based on an initial allocation of the capacity to each country based on GDP. Countries with a low GDP per citizen would then have a smaller share of the carrying capacity per citizen and the countries with a higher GDP per citizen would have a larger share. Seen isolated on the building sector this would imply that a building with the same environmental impact in i.e. Europe and Africa could be evaluated respectively sustainable and non-sustainable due to the difference in allocated capacity. This approach is though found too contradictory to the sustainability term as it favours some human beings over others, and is therefore omitted from the study. There are thus many challenges and ambiguities associated with the allocation of the carrying capacity, and the “fair share” allocated to the building may vary with perspective. The economic allocation method based on the person equivalent capacity was chosen to form the basis for the result normalization in the subsequent analysis in the study, resulting in an allocation of 11,2% of the person equivalent carrying capacity in all impact categories. This is however not tantamount to defining this method as the most fair or proper method, but based on the fact, that the economic allocation method is more widely accepted as allocation method. The economic allocation method chosen as the analysis basis is the one, out of the three methods, allocating the largest share of the carrying capacity in all impact categories, except for the climate change category. Depending on the allocation method, the carrying capacity allocated to the dwelling would therefor most likely be even smaller than the one used as the analysis basis, with an even larger transgression of the boundaries as a result.
  • 63. DISCUSSION       55/74 5.2 Environmental pressure from current construction methods Besides the model used in the validation process, the LCA models are based on a wider boundary system than normally used in building LCA’s, see a detailed description in section 3.2. The system boundaries of the LCA are widened out based on the assumption, that this will increase the probability of the buildings resulting impacts, estimated through the LCA, being closer to the dwelling’s absolute impacts. In the prevalent approach to building LCA certain areas, such as the construction phase, is left out due to uncertainties and variations which complicates benchmarking of buildings. The validation process of the model build-up, where the prerequisites in form of system boundaries, materials etc. were sought identical to those of the SBI studies, showed large deviations on the output results. From the Standard house the deviation from the SBI results were +15% and for the Upcycle house it was +100%. The identified resulting impacts from the building are thus seen dependent on presumptions made along the LCA as well as the background data used. This underlines the “non-absoluteness” of the identified resulting impacts from the buildings. 5.2.1 Standard house The Single-family house is the most prevalent housing type in Denmark representing 43% (Statistic Denmark, 2015) of all housing units, and the Standard house used in the project represents prevalent Danish construction design and material choices. The resulting environmental impact from the Standard house is therefore assumed representative for a typical new built Danish single-family house built according to LEK2015. When the impact from the LCA was normalised according to the carrying capacity allocated to the building using the allocation method based on economic value, the Standard house was seen to exceed the capacity immensely within two categories; climate change and freshwater eutrophication. The climate change boundary was seen transgressed with up to a factor 15 depending on the capacity definition, and the freshwater eutrophication with a factor 4. Further more the impact from the Standard house was seen to approach the boundaries of additionally two categories; freshwater ecotoxicity and water depletion. It thus clearly shows how the Standard house impacts the environment in a way that is far from sustainable. Based on the analysis a development into an absolute sustainable state is seen to require a cutback of more than 90% on current climate change impact from the dwelling, and more than 80% cutbacks on freshwater eutrophication impacts.
  • 64.   DISCUSSION   56/74   5.2.2 Upcycle house The Upcycle house represent state-of-the-art in Denmark within reducing the environmental impact from the building materials, and the analysis shows that the impact on climate change is reduced by 30% compared to the Standard house if all impacts are included. If only looking at material and construction the decrease in impact on climate change is seen to be 65% compared to the standard house. Although the impacts from material and construction are remarkably reduced from the Standard house to the Upcycle house, the impacts from the Upcycle house is still far from absolute sustainable. The impact on climate change is seen to transgress the capacity with up to a factor 10 and the freshwater with a factor 3,5. The pressure on water depletion is seen decreased from an impact corresponding to 74% of the capacity from the Standard house to 61% for the Upcycle house. For the freshwater ecotoxicity the pressure is seen reduced from an impact corresponding to 94% of the capacity to 87% of the capacity for the Upcycle house. The general picture is still clear though, when it comes to the impact on climate change and freshwater eutrophication, the Upcycle is far from absolute sustainability. 5.2.3 Sensitivity analysis From the sensitivity analysis the determination of the carrying capacity as well as the building impacts is seen to be important. The Standard house is however still seen far from absolute sustainable even if the calculated carrying capacity is assumed underestimated by 15% as well as the building impacts is assumed overestimated by 15% (scenario 3). In that case the climate change capacity is still transgressed by a factor 10 and the freshwater eutrophication with a factor 3. The sensitivity analysis thus underlines that both the standard house and the Upcycle house is far from absolute sustainability, but it also underlines the importance of estimating both carrying capacity as well as building impact as correct and close to reality as possible. 5.3 Validation of model build-up The validation process provided a foundation for a critically examination of the model build-up as well as an identification of the possible result deviations on LCA’s carried out with a wide range of identical prerequisites. The deviation of the resulting GWP impact is though seen +15% on the reference house model and +100% on the Upcycle house model, even though many of the basic prerequisites were identical to the ones used by SBI. When it comes to the remaining four impact categories, the deviations were seen to be remarkable higher than for the GWP, ranging between +75% for AP up to +388% for EP. Even though the prerequisites are strived to be alike, there are though many parameters such as database type, conversion factors etc. that have influence on the output and can vary from LCA to LCA, and with no clear right or wrong answer. From the validation process it thus clearly shows how the resulting impacts may
  • 65. DISCUSSION       57/74 contain large deviations due to assumptions made in the LCA, even though the initial inventory basis is the same. This validation process thus contributes to an important insight into the absoluteness or non-absoluteness of the determination of buildings environmental impact, and how this can deviate notable from one analysis to another, even when based on the same methodological approach and the same basic inventory data. If the inventory data were also individually collected one could only imagine what this would result in deviations between models. 5.4 The absolute sustainable building As described above both the Standard house and the Upcycle house are far from absolute sustainability. The following section will thus discuss the potential of reducing the impacts and obtaining an absolute sustainable building. To reduce the impacts from the Standard house four key parameters were identified: • Use phase energy (heat and electricity), impacts per m2 • Materials and construction, impacts per m2 • Living area per person (building size) • Projection of the carrying capacity In the following the potential of each parameter is identified followed by a development of three scenarios leading to the absolute sustainable building in 2050. 5.4.1 Use phase energy From the results described in section 4.3 the use phase energy is seen to contribute significantly to the buildings environmental impacts. For the Standard house the use phase energy constitute 56% of the climate change impact when built according to LEK2015, and 40% when according to BK2020. The size of the impacts from use phase energy per square meter building is dependent on two primary parameters; the magnitude of the energy consumption as well as the energy supply mix. From section 4.3.1 the effect of a decrease in energy consumption from LEK2015 to BK2020 on the Standard house is illustrated. The exploitation of the climate change capacity is seen reduced by 25% from 1563% to 1152%. The transgressions are though still immense, and even if the energy consumption during the use phase is zero the impacts from the building’s transgression of the capacity is still significant. The same tendencies are seen for the Upcycle house. The projection of the energy supply mix is an important factor for the future impact of the buildings since the ratio of respectively fossil- and renewable fuels is of great importance when the impact per kWh is
  • 66.   DISCUSSION   58/74   determined. The Danish energy policy is aiming at a fossil free energy mix in 2050, which will cause the environmental impacts per kWh to decrease. 5.4.2 Materials and construction The impacts from materials and construction is representing 44% of the climate change impact when the Standard house is built according to LEK2015, and 60% when built according to BK2020, and is thus seen as an important factor when reducing the buildings total impact. From the total impact from materials and construction the impact from construction energy represent around 12% for the Standard house but 35% for the Upcycle house. Reducing the impact from materials is thus seen as an important factor in reducing the total impact from the building, but also reducing the energy for constructing the building is relevant and the importance of the construction energy is seen to increase the more the impact from materials is reduced. For materials and construction to constitute 44% of the climate change impact is somewhat higher than identified in other similar studies (SBI, 2015; SBI, 2013), and this divergence is presumed rooted in two things; lifetime assumptions and system boundaries. This analysis is based on a building lifetime of 50years, and if an increased lifetime is assumed, naturally the impact from materials and construction is distributed over a longer period of time and thus decreasing the yearly impact. Secondly the current analysis is based on wider boundaries than commonly used in building LCA’s to obtain more absolute impacts. Some of the bigger variations in boundaries concern inclusion of the construction phase as well as additional transport processes, which both contribute to an increased weight of material and construction. Besides reducing the impact from materials through reducing the quantity of material used as well as using low-impact materials, the lifetime of the building also plays an important role. As the lifetime influence on the yearly impact from materials and construction is distributed over a longer period of time when the lifetime is increased. The building lifetime used in the LCA is 50 years, corresponding to the lifetime used by DGNB. The influence of an increased lifetime from 50 to 120years was therefore identified, see section 4.4. Additional replacements of building elements was included in the analysis, but normally when a building lifetime exceeds 40-50 years it needs profound modernizations to be contemporary and this additional use of material was not included in the analysis. When the lifetime of the Standard house was increased to 120 years, the yearly impact solemnly from materials and construction where seen to decrease by 40% on the climate change impact and by 30% on freshwater eutrophication. With the Upcycle house the decreases where seen slightly higher with 43% on climate change impact and 33% on freshwater eutrophication. Increasing the building lifetime without adding the need for additional modification, implying a contemplated design and material selection in the building design phase, is thus seen to reduce the impact from materials remarkably.
  • 67. DISCUSSION       59/74 5.4.3 Living area per person An effective way to decrease the total impact from the building would be to decrease the living area per person, this both influence on the amounts of materials as well as the use phase energy. To visualize the effect of a decreased living area, the impacts relative to the carrying capacity are illustrated according to the size of the living area in Graph 2. Graph 2 Influence of living area per person on the impact relative to the carrying capacity. Based on the Upcycle house with energy consumption according to LEK2015. If built according to the Upcycle house and with energy consumption according to LEK2015 the area per person only amounts to around 5m2 if the environmental impact is to stay within the carrying capacity. Currently the living area per person is seen to be 40m2 for the Upcycle house in its original size (104 m2 ), 49 m2 for the Standard house and 53m2 for the average Danish dwelling. If the energy consumption is decreased to comply with BK2020, Graph 3 shows how the area per persons rises slightly from 5m2 to around 7 m2 if staying within the carrying capacity. 0   200   400   600   800   0   5   10   15   20   25   30   35   40   45   50   55   Impact  relative  to  carrying  capacity  [%]   Living  area  [m2/person]   Relation  between  living  area  and  relative  impact   -­‐  Upcycle  house  Br2015  -­‐   Terrestrial  acidiXication   Water  depletion   Landuse,  biodiversity   Climate  change,  temp   Climate  change,  rad.  Forc   Ozone  depletion   Freshwater  eutrophication   Marine  eutrophication   Terrestrial  eutrophication   Ozone  formation   Freshwater  ecotoxicity   Carrying  capacity   Upcycle  house   Standard  house   DK  Average   Freshwater  eutrophication  
  • 68.   DISCUSSION   60/74   Graph 3 Influence of living area per person on the impact relative to the carrying capacity. Based on the Upcycle house with energy consumption according to BK2020. The correlation between the relative impact and the living area is assumed linear, and is based on the impact per square meter found in the LCA based on the house in its full size. This is though a simplification, since the impact per square meter supposedly would increase des smaller the house. Some of the building impacts are not dependent on the area but would be similar no matter the total area, i.e. hot water tank etc., but with a smaller living area the impact from these non-area dependent impacts would be distributed over fewer square meters leading to an increased impact per square meter. The societal trend though is not decreasing but increasing living areas, and from 1981 to 2014 the average living area per person in Denmark rose with 21% from 42,9m2 in 1981 to 52,1m2 in 2014, see Graph 4. The average unit size though only rose around 5% in the same period, and the increase in living area per person is therefor presumably due to a decreased number of people per unit and not solemnly due to an increased building size. 0   200   400   600   800   0   5   10   15   20   25   30   35   40   45   50   55   Impact  relative  to  carrying  capacity  [%]   Living  area  [m2/person]   Relation  between  living  area  and  relative  impact   -­‐  Upcycle  house  Br2020  -­‐   Terrestrial  acidiXication   Water  depletion   Landuse,  biodiversity   Climate  change,  temp   Climate  change,  rad.  Forc   Ozone  depletion   Freshwater  eutrophication   Marine  eutrophication   Terrestrial  eutrophication   Ozone  formation   Freshwater  ecotoxicity   Carrying  capacity   Climate  change,  temp.   Freshwater  eutrophication   Upcycle  house   Standard  house   DK  average  
  • 69. DISCUSSION       61/74 Graph 4 Average living area per person in Denmark from 1981-2014 (Statistic Denmark, 2015) 5.4.4 Projection of the carrying capacity The carrying capacity is throughout the analysis stated as a person equivalent and threated as a static figure. However, this is a simplification in several aspects. Ecosystems as well as our climate are complex systems, which are interrelated in a comprehensive net of feedback-mechanisms and the carrying capacity of these systems would most likely differ over time as well as with a changing pressure. In the following the worlds total environmental carrying capacity is assumed constant, and a decline in carrying capacity ie. when the pressures over a period of time exceeds the capacity is thus not considered. A more straightforward projection of the person equivalent carrying capacity is though based on population growth. If the total carrying capacity were assumed stable, a growth in population would most naturally lead to a decline in carrying capacity per person. To identify the influence of population growth on the person equivalent carrying capacity a projection is carried out based on population prospects from UN (2013). The person equivalent is initially estimated on a population of 6,92 billion people globally in 2010 (Bjørn & Hauschild, 2015), and from population projections from the UN the population in 2050 would have increased to around 9,55 billion people and in 2100 to around 10,9 billion (UN, 2013). 0   50   100   150   0   20   40   60   1980   1985   1990   1995   2000   2005   2010   2015   Unit  size  [m2/unit]   Living  area  per     [m2/person]   Average  living  area  per  person,  DK   Living  area   Unit  size  
  • 70.   DISCUSSION   62/74   Graph 5 Projection of the decline in person equvivalent carrying capacity allocated to the building due to population growth. Here illustrated on the global warmning potential. Population project according to UN (2013) From Graph 5 it shows how the carrying capacity per person will decline due to an increased global population. From 2010-2050 the carrying capacity per person will decline by 28% alone due to population growth and again from 2050-2100 a decline of additionally 12% is seen. This corresponds to a total decline in carrying capacity from 2010 to 2100 of 37% due to global population growth alone. 5.4.5 Scenarios 2050: The absolute sustainable building The Standard house represents the prevalent single-family housing type today, and the development of three scenarios for the absolute sustainable building in 2050 therefore takes its basis in the Standard house. To obtain the needed changes for the Standard house to become absolute sustainable four key parameters have been identified; use phase energy, materials and construction, living area per person and the projection of the carrying capacity. First the potential of each of the four parameters is assessed and then followed by the three scenarios identifying a range of parameter changes leading to absolute sustainability in 2050. The projection of the carrying capacity is maintained as illustrated in Graph 5 for all scenarios and only the three remaining parameters are modified. 5.4.5.1 Scenario 1 Scenario 1 is based on a modification of all three free parameters. From Figure 25 it shows how a reduction of 93% on respectively the impact per square meter from both use phase energy and materials are required together with a reduction of the living area on 39% if the building is to be absolute sustainable in 2050. The reduction of 93% on use phase energy corresponds to a climate change impact of 0,78 kgCO2eq/m2 in 2050. The climate change impact in 2015 is 10,4kgCO2/m2 , and if built according to BK2020 and with the current energy supply mix the climate change impact would be 5,5kgCO2eq/m2 . If the Standard house were built according to BK2020 the absolute sustainability would thus still require an additional 86% reduction. 0,00   5,00   10,00   15,00   0   50   100   150   2010   2020   2030   2040   2050   2060   2070   2080   2090   2100   Population    [billions]   Capacity    [kgCo2/person/yr]   Carrying  capacity,  GWP   Allocated  to  the  building,  based  on  exonomic  allocaion   Capacity,  GWP   Population  
  • 71. DISCUSSION       63/74 When it comes to the impact from material and construction the 93% reduction corresponds to an impact of 0,62kgCO2eq/m2 in 2050. If put into perspective, the impact from the Upcycle house is 2,82kgCO2eq/m2 , and the reduction required from the Standard house is thus an additional 78% from the Upcycle house impact. If the lifetime of the Upcycle house were prolonged to 120years the climate change impact would decrease to 1,7kgCO2eq/m2 , which is still almost a factor 3 more than the required 0,62kgCO2eq/m2 . When it comes to the living area, the reduction of 39% corresponds to a living area per person of 30m2 in 2050, and with an average of 2,6 person per building this corresponds to a single-family house of 78m2 . Scenario 1: The absolute sustainable building 2050 Use phase energy [kgCO2eq/m2 /yr] Material and construction [kgCO2eq/m2 /yr] Living area per person [m2 ] Carrying capacity [kgCO2eq/building/yr] Use phase energy [kgCO2eq/m2 /yr] Material and const. [kgCO2eq/m2 /yr] Living area [m2 /person] Carrying capacity [kgCO2eq/build/yr] 2015 10,4 8,2 49 152 2050 0,78 0,62 30 109 2050/2015 ratio 0,075 0,075 0,612 0,717 Figure 25 Requiered changes for the Standard house to reach absolute sustainability in 2050, Scenario 1 The reductions needed in order to reach absolute sustainability in 2050 are immense. Even if the living area is reduced by 40% the impact from use phase energy per square meter needs to reach a level corresponding to an 86% reduction compared to BK2020 and the impact from materials per square meter needs to reach a level corresponding to an 78% reduction of the impact from Upcycle house. 0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   20   40   60   2015   2020   2025   2030   2035   2040   2045   2050   0   100   200   2015   2020   2025   2030   2035   2040   2045   2050  
  • 72.   DISCUSSION   64/74   5.4.5.2 Scenario 2 In scenario 2 the living area person is kept constant at an area of 49m2 , equal to the current living area per person of the Standard house, and only the impact from use phase energy and material and construction are altered. From Figure 26 the required changes for the scenario is illustrated, and it shows how the reduction of the impacts from use phase energy and material and construction is required to be 96% when the living area is kept constant. Scenario 2: The absolute sustainable building 2050 Use phase energy [kgCO2eq/m2 /yr] Material and construction [kgCO2eq/m2 /yr] Living area per person [m2 ] Carrying capacity [kgCO2eq/building/yr] Use phase energy [kgCO2eq/m2 /yr] Material and const. [kgCO2eq/m2 /yr] Living area [m2 /person] Carrying capacity [kgCO2eq/build/yr] 2015 10,4 8,2 49 152 2050 0,47 0,37 49 109 2050/2015 ratio 0,045 0,045 1 0,717 Figure 26 Requiered changes for the Standard house to reach absolute sustainability in 2050, Scenario 2 5.4.5.3 Scenario 3 In scenario 3 the impact from materials and construction is kept constant, indicating a continuous use of current building materials and the remaining two parameters, impact from use phase energy and living area are altered, see Figure 27. Continuous use of current building materials and construction methods thus require a 90% reduction on the impact from use phase energy per square meter as well as a 90% reduction of the actual living area. 0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   20   40   60   2015   2020   2025   2030   2035   2040   2045   2050   0   100   200   2015   2020   2025   2030   2035   2040   2045   2050  
  • 73. DISCUSSION       65/74 Scenario 3: The absolute sustainable building 2050 Use phase energy [kgCO2eq/m2 /yr] Material and construction [kgCO2eq/m2 /yr] Living area per person [m2 ] Carrying capacity [kgCO2eq/building/yr] Use phase energy [kgCO2eq/m2 /yr] Material and const. [kgCO2eq/m2 /yr] Living area [m2 /person] Carrying capacity [kgCO2eq/build/yr] 2015 10,4 8,2 49 152 2050 1,04 8,2 4,9 109 2050/2015 ratio 0,1 1 0,1 0,717 Figure 27 Requiered changes for the Standard house to reach absolute sustainability in 2050, Scenario 3 5.5 Uncertainties and future work As identified in the literature study there is virtually no preceding work on coupling building environmental impacts to carrying capacity. The work in this master’s thesis is thus only in the preliminary stages of identifying an absolute sustainability assessment for buildings, and refinement of the method in many aspects is required. 5.5.1 Carrying capacity For the identification of the carrying capacity allocated to the dwelling there is two main uncertainties; the capacity estimations and the following allocation of a share to the dwelling. 0,0   5,0   10,0   15,0   2015   2020   2025   2030   2035   2040   2045   2050   0   5   10   15   2015   2020   2025   2030   2035   2040   2045   2050   0   20   40   60   2015   2020   2025   2030   2035   2040   2045   2050   0   100   200   2015   2020   2025   2030   2035   2040   2045   2050  
  • 74.   DISCUSSION   66/74   According to Bjørn & Hauschild (2015) there are several important uncertainties related to the estimation of carrying capacity. For instance the estimates are based on models simplifying reality, but also the definition of carrying capacity involves ambiguities and is by Bjørn & Hauschild (2015) based on scientific consensus. In this study the carrying capacity was only allocated to dwellings, but an allocation to the remaining building types such as offices and schools is also relevant to carry out. Allocation to the remaining building types will though most likely be more complicated than to the dwelling, since the inventories on for instance the economic values they represent might not be as clear and distinctly identified as for the dwellings, since the dwellings could be identified via the household budget. The allocation was carried out using respectively one method based on economic value and two based on current environmental pressure. As mentioned earlier there are pros and cons in both the economic and the environmental allocation approach, and additional work on a possible merging of the two methods so both economic value and environmental pressure were accounted for could be interesting. The work on allocating the carrying capacity is though more a political issue than an engineering issue, and the future work ought to involve social scientist for instance. 5.5.2 Quantification of absolute impacts An LCA is initially indented for a relative performance indication. Evaluating the absolute sustainability though implies that the identified impacts from the building reflect the absolute (or total) impacts. Identifying the absolute impacts through an LCA therefore needs a refinement of the methodology. The characterisation method for the impact characterisation also includes uncertainties and would require additional work, in the study the characterisation of land erosion especially stood out. For the impact estimations made in this study to approach the absolute impacts even more, the estimation of the energy consumption of the building would need additional work. The energy consumption used in the study was related to the Danish energy frame, and the actual energy consumption is known to differ from this. Besides the fact that only the building regulated energy consumption was included, leaving out electricity for appliances, lighting etc., energy consumption is also seen to vary from residents to residents. Apart from the energy consumption there are ambiguities in defining what impacts should be included in the absolute impacts from the building. A building has a lot of derived effects, and for instance a specific building design could promote an energy saving behaviour, as well as a building close to public transportation could reduce the residents impacts from transportation. Further more the quantification of environmental impacts were only carried out for a single-family house, but identifying it for the remaining housing types such as apartments and townhouses would also be interesting. Also the impact of the remaining building types such as offices and schools are interesting. Further more a study of the impacts from the existing building mass could be an important step, since a great deal of the environmental impacts from buildings is bound within the existing building mass.
  • 75. DISCUSSION       67/74 When developing scenarios that are reaching absolute sustainable buildings in the future the energy supply mix is an important factor when determining the impacts from the use phase energy. A projection of the energy mix is not included in this study, and including this is an important step in the future works on the scenario development. Additionally a study of the influence of energy producing facilities such as solar- or earth heat related to the building would be interesting.
  • 77. CONCLUSION  AND  RECOMENDATIONS       69/74 6 CONCLUSION AND RECOMENDATIONS The developed normalisation method allows for an absolute sustainability assessment of a building, where the building impacts are compared to the share of environmental carrying capacity that by a fair distribution are allocated to the building. As a basis for the normalisation, different allocation scenarios were carried out to identify the “fair share” of the environmental carrying capacity that should be allocated to the building. An allocation of 11,2% of the person equivalent carrying capacity in all impact categories were used as a basis for the further analysis, but the allocation process provided an important insight into the complexity of the allocation, and the share used as analysis basis should not be considered definite. An absolute sustainability assessment were carried out on two reference buildings, a standard house representing the prevalent Danish single-family house in both size and construction type and a building representing state-of-the-art when comes to reducing environmental impacts from materials. The assessment showed that both buildings were far from absolute sustainability. The carrying capacities were immensely transgressed on climate change and freshwater eutrophication for both buildings. Further more the impact on both water depletion and freshwater ecotoxicity were approaching the limits for both the Standard house and the Upcycle house. Due to a rising population the carrying capacity was found to decline by 28% from 2010 to 2050. This decline was combined with a projection of three scenarios leading to absolute sustainable buildings in 2050. The common denominator for the three scenarios were the immense reductions needed, and for instance if the living area were reduced by 40% by 2050, the impacts from use phase energy should be reduced with 93% and the same reduction would be needed for the impacts from materials and construction to reach absolute sustainability.
  • 78.   CONCLUSION  AND  RECOMENDATIONS   70/74  
  • 79. REFERENCES       71/74 7 REFERENCES Aysin, S., 2011. A comparative analysis of building environmental assessment tools and suggestions for regional adaptations. Civil Engineering and Environmental Systems, September. pp.231-45. Bendewald, M. & Zhai, Z.., 2013. Using carrying capacity as a baseline for building sustainability assessment. Habitat International, pp.22-32. Beradi, U., 2012. Sustainability Assessment in the Construction Sector: Rating Systems and Rated Buildings. Sustainable Development, pp.411-24. Birkved, M. & Goldstein, B., n.d. Environmental sustainability assessment of urban systems applying coupled urban metabolism and life cycle assessment. In Höfler, K., Maydl, P. & Passer, A., eds. Proceedings of the sustainable buildings - Construction products and Technologies: Collection of full papers. Graz Verlag der Technischen Universität Graz. Bjørn, A., Diamond, M.L., Birkved, M. & Hauschild, M.Z., 2014. A chemical footprint method for improved communication of freshwater ecotoxicity impacts in the context of ecological limits. Environmental Science & Technology, 27. October. Bjørn, A. & Hauschild, M.Z., 2015. Introducing carrying capacity based normalisation in LCA: framework and development of midtpoint level references. The International Journal of Life Cycle Assessment. The article is currently in for review, 21.january 2015. BREEAM, 2015. Building Research Establishment Environmental Assessment Method. [Online] Available at: www.breeam.org [Accessed 27 January 2015]. For amount of certified building see: http://www.breeam.org/about.jsp?id=66. CASBEE, 2015. Comprehensive Assessment System for Built Environment Efficiency. [Online] Available at: www.ibec.or.jp [Accessed 27 Janyary 2015]. For method see: http://www.ibec.or.jp/CASBEE/english/methodE.htm. Cuéllar-Franca, M.R. & Azapagic, A., 2012. Environmental impacts of the UK residential sector: Life cycle assessment of houses. Building and Environment, pp.86-99. DGNB, 2015. Deutche Gesellschaft für Nachhaltiges Bauen. [Online] Available at: www.dgnb-system.de [Accessed 23 January 2015]. For number of consultants and auditors see: http://www.dgnb-
  • 80.   REFERENCES   72/74   system.de/en/certification/dgnb-auditors-consultants/ For number of certified buildings see: http://www.dgnb-system.de/en/projects/. DiMento, J.F.C. & Doughman, P., 2007. Climate change: What it means for us, our children and our grandcihldren. Cambridge: MIT Press. DK-GBC, 2014. DGNB system Denmark manual for kontorbygninger 2014 1.1. Denmark: DK-GBC Green building council Denmark. DK-GBC, 2015. Green Building Council Denmark. [Online] Available at: www.dk-gbc.dk [Accessed 23 January 2015]. Ecoinvent, 2007. Overview and methodology - Data v2.0 (2007). Ecoinvent report no.1. Dübendorf: Swiss centre for life cycle inventories. EEA, 2013. No 2/2013 Environmental pressures from European consumptrion and production. Technical report. Copenhagen: European Environmental Agency European Environment Agency. ISSN 1725-2237, doi:10.2800/70634. EPD Danamark, 2015. EPD Danmark. [Online] Available at: www.epddanmark.dk [Accessed 11 Feburary 2015]. European Commission, 2006. Environmental Impact of Products (EIPRO) - Analysis of the life cycle environmental impacts related to the final consumption of the EU-25. Technical Report EUR 22284 EN. Spain: European Comission. Eurostat, 2015. European comission. [Online] Available at: http://ec.europa.eu/eurostat [Accessed March 2015]. FOEN, 2011. Environmental Impacts of Swiss Consumption and Production - A combination of input-output anlysis with life cycle assessment. Bern: FOEN Foderal Department of Environment, Transport, Energy and Communication (DETEC). Giama, E. & Papadopoulos, A.M., 2012. Sustainable building management: Overview of certification schemes and standards. Advances in Building Energy Research, October. pp.242-58. Global Footprint Network, 2010. Ecological Footprint Atlas. Oakland: Global Footprint Network. Haapio, A. & Viitaniemi, P., 2008. A critical review of building environmental assessment tools. Environmental Impact Assessment Review, pp.469-82. iiSBE, 2015. International Initiative for a Sustainable Built Environment. [Online] Available at: www.iisbe.org [Accessed 27 January 2015]. For scope and method see: http://iisbe.org/sbmethod.
  • 81. REFERENCES       73/74 Kajikawa, Y., Inoue, T. & Goh, T.N., 2011. Analyss of building environment assessment frameworks and their implications for sustainability indicators. Sustainable Science, pp.233-46. DOI 10.1007/s11625-011- 0131-7. Matheus, R. & Bragança, L., 2011. Sustainability assessment and rating of buildings: Developing the methodology SBTool-H. Building and Environment, pp.1962-71. Minter, M., 2014. Bygningers klimapåvirkning i et livscyklusperspektiv. Rapport. København: CONCITO CONCITO. www.concito.dk. Olgyay, V. & Herdt, J., 2004. The application of ecosystems services criteria for green building assessment. Solar energy, 26 February. pp.389-98. Rockström, J., Steffen, W., Noone, K. & Persson, Å., 2009. A safe operating space for humanity. Nature, 24 September. SBI, 2013. Livscylkusvurdering af MiniCO2-husene i Nyborg. Copenhagen: Statens byggeforskninginstitut Aalborg Universitet. SBI, 2015. Bygninges livscyklus - Identifikation af væsentlige bygningsdele, materialegrupper og faser i en miljømæssig vurdering. Copenhagen: Statens Byggeforskningsinstitut Aalborg University. http://www.sbi.dk/miljo-og-energi/beredygtighedsvurdering/bygningens-livscyklus/bygningens-livscyklus. Sharifi, A. & Murayama, A., 2013. A critical review of seven selected neighborhood suustainability assessment tools. Environmental Impact Assessment Review, pp.73-87. doi:10.1016/j.eiar.2012.06.006. Siew, R.Y.J., Balabat, M.C.A. & Carmichael, D.G., 2013. A review of building/infrastructure sustainability reporting tools (SRTs). Smart and Sustainable Built Environment, pp.106-39. Statistic Denmark, 2015. Statistic Denmark. [Online] Danmarks statistik Available at: www.dst.dk [Accessed 01 May 2015]. http://www.dst.dk/pukora/epub/upload/19005/dk2015.pdf and http://www.dst.dk/da/Statistik/emner/boligforhold/beboere.aspx. U.S. GBC, 2015. U.S. Green Building Council. [Online] Available at: www.usgbc.org [Accessed 26 January 2015]. See http://www.usgbc.org/leed#credits. UN, 1987. Report of the World Commission on Environment and Development: Our Common Future. New York: United Nations. See unpopulation.org. UN, 2013. The world population prospect - 2012 revision. New York: United Nations United Nations. www.unpopulation.org.
  • 82.   REFERENCES   74/74   UNEP, 2009. Buildings and climate change: Summary for policy makers. UNEP. United Nations, 2015. United Nations Statistic Division. [Online] Available at: http://unstats.un.org [Accessed 20 March 2015]. COICOP is to bee found on URL: http://unstats.un.org/unsd/cr/registry/regcst.asp?Cl=5. Van den Bergh, J.C.J.M. & Grazi, F., 2013. Ecological Fotprint Policy? Land Use as an Environmental Indicator. Journal of Industrial Ecology, pp.10-19. DOI: 10.1111/jiec.12045. Weissenberger, M., Jensch, W. & Lang, W., 2014. The convergence of life cycle assessment and nearly zero-energy buildings: The case of Germany. Energy and Buildings, 24 March. pp.551-57.    
  • 83. Appendices - The absolute sustainable building – TABLE OF CONTENT APPENDIX  A:  INVENTORY  LIST  UPCYCLE  HOUSE  ...........................................................................................  1   APPENDIX  B:  INVENTORY  LIST  STANDARD  HOUSE  .......................................................................................  4   APPENDIX  C:  END  OF  LIFE  FLOWS  .......................................................................................................................  6   APPENDIX  D:  MATERIAL  PROPERTIES  ..............................................................................................................  8   APPENDIX  F:  ENVIRONMENTAL  IMPACTS  ........................................................................................................  9   APPENDIX  G:  PROLONGED  LIFETIME  ...............................................................................................................  10   STANDARD  HOUSE  (EXCLUDING  USE  PHASE  ENERGY)  ...........................................................................................................  10   UPCYCLE  HOUSE  ............................................................................................................................................................................  11   APPENDIX  H:  SENSITIVITY  -­‐  SUB  CATEGORIES  .............................................................................................  12   APPENDIX  I:  MODEL  VALIDATION  .....................................................................................................................  13   1.1.1   Alternation  of  models  ..............................................................................................................................................  13   1.1.2   Sources  of  errors  ........................................................................................................................................................  14   APPENDIX  J:  SUB-­‐CAT.  EXPENSES  CP04-­‐05  ....................................................................................................  16   APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)  .............................................................................  18  
  • 85. APPENDIX  A:  INVENTORY  LIST  UPCYCLE   HOUSE       1/22 APPENDIX A: INVENTORY LIST UPCYCLE HOUSE Mass [kg/m2] Service life [yr] Upcycle factor Ecoinvent dataset EoL flow Foundations Screwfoundation 14 120 0,12 RER: Steel, low alloyed, at plant 3 Concrete (plates) 28 120 0,12 CH: Concrete, normal, at plant 1 Gravel 249 120 CH: Gravel, crushed, at mine 4 Ground slab0,12 Container 16 120 RER: Steel, low-alloyed, at plant 3 Plast foil 0,4 120 RER: Polyethylene, LDPE, granulate, at plant 5 EPS 4,7 120 0,35 RER: Polystyren foam slab, at plant 2 Wood laths 2,2 120 0,12 RER: Sawn timber, softwood, planned, air, at plant 8 Paperwool insulation 10 120 See datasets in table below 14 Outer walls Richlite composite 8,3 60 0,37 x RER: phenolic resin, at plant + 0,63 x RER: waste paper, sorted, for further treatment 18 Paperwool insulation 22 60 See datasets in table below 14 Plaster (wind) 14 60 0,35 CH: gypsum plaster board, at plant 7 Container 22 120 0,12 RER: steel, low-alloyed, at plant 3 Plast foil 0,3 60 RER:polyethylene, LDPE, granulate, at plant 5 Trapezodial sheets (alu) 0,7 40 0,67 RER: aluminium alloy, AlMg3, at plant 11 Plaster board 29 40 0,35 CH: gypsum plaster board, at plant 7 Structural timber 0,5 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Inner walls Container 22 120 0,12 RER_ steel, low-alloyed, at plant 3 OSB-plates 24 25 RER: oriented strand board, at plant 8 Paperwool insulation 4,0 60 See datasets in table below 14 Structural timber 1,6 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Poli brick 0,9 60 0,5 RER: polyethylene terephthalate, granulate, bottle grade, at plant 15 Roof Plaster board 8,7 40 0,35 CH: gypsum plaster board, at plant 7
  • 86.   APPENDIX  A:  INVENTORY  LIST  UPCYCLE  HOUSE   2/22   Structural timber 15 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Container 1,9 120 0,12 RER_ steel, low-alloyed, at plant 3 Paperwool insulation 23 40 See datasets in table below 14 Trapezodial sheets (alu) 3,2 40 0,67 RER: aluminium alloy, AlMg3, at plant 11 Doors and windows Windows (3-layer, thermo) 18 25 0,12 RER: glazing, triple (3-IV), U<0,5W/m2K, at plant 10 Window frame 0,6 50 0,67 RER: window frame, aluminium, U=1,6W/m2K, at plant 11 Silicone sealants 0,1 50 RER: polysulphide, sealing compound, at plant 16 Wooden door 4,5 60 0,35 RER: door, inner, wood, at plant 8 Floors and surfaces Structural timber 7,4 120 0,14 RER: sawn timber, softwood, planed, kiln dried, at plant 8 OSB-plates 14 40 0,6 RER: oriented strand board, at plant 8 Tiles, non-glazed 2,2 60 CH: ceramic tiles, at regional storage 4 Paint, water based 0,1 10 0,5 RER: alkyd paint, white, 60% in H2O, at plant 12 Installations Water pipes 0,1 60 RER: steel, low-alloyed, at plant 3 Sanitary ceramics 0,3 40 CH: sanitary ceramics, at regional storage 4 Hot water tank 0,4 30 CH: hot water tank 600l, at plant 3 Heaters 1,8 30 0,3 RER:steel, low-alloyed, at plant 3 Circulation pump 0,05 20 CH: pump, 40W, at plant 3 Ventilation unit 1,3 25 CH: ventilation system, decentralized, 6x120m3/h, steel ducts, without GHE 3 Terrace and greenhouse UPM composite 9,4 60 0,35 0,31*RER: polyethylene, LDPE, granulate, at plant + 0,69* CH: cellulose fibre, inclusive blowing in, at plant 14 Brick wall (old bricks) 41 120 0,5 RER: brick, at plant 4 Mortar (wall) 8,5 120 CH: cement mortar, at plant 6 Brick floor (old bricks) 45 120 0,5 RER: brick, at plant 4 Mortar (floor) 9,4 120 CH: cement mortar, at plant 6 Window panes 2,5 80 0,12 RER: flat glass, uncoated, at plant 17
  • 87. APPENDIX  A:  INVENTORY  LIST  UPCYCLE   HOUSE       3/22 Glassshaum granulate (insulation) 10 120 RER: foam glass, at plant 4 Paperwool Share of mass Dataset 0,02 RER: tap water, at user 0,05 RER: boric acid, anhydrous, powder, at plant 0,01 RER: borax, anhydrous, powder, at plant 0,07 RER: aluminium hydroxide, at plant 0,85 RER: waste paper, sorted, for further treatment
  • 88.   APPENDIX  B:  INVENTORY  LIST  STANDARD  HOUSE   4/22   APPENDIX B: INVENTORY LIST STANDARD HOUSE Mass [kg/m2] Service life [yr] Ecoinvent dataset EoL flow Foundations Concrete 227 120 CH: concrete, normal, at plant 1 Light weight concrete 25 120 CH: lightweight concrete block, expanded perlite, at plant 1 EPS 1,5 120 RER: polystyren foam, at plant 2 Ground slab Concrete 232 120 CH: concrete, normal, at plant 1 Reinforcement steel 14 120 RER: reinforcing steel, at plant 3 EPS 5,5 120 RER: polystyren foam, at plant 2 Gravel 320 120 CH: gravel, crushed, at mine 4 Plast foil 0,1 120 RER: polyethylene, LDPE, granulate, at plant 5 Outer walls Aerated concrete 41 120 CH: autoclaved aerated concrete block, at plant 1 Mineral wool 10 120 CH: glass wool mat, at plant 4 Brick 137 120 RER: brick, at plant 4 Mortar 29 120 CH: cement mortar, at plant 6 Inner walls Aerated concrete 35 100 CH: autoclaved aerated concrete block, at plant 1 Plaster (filler) 3,4 40 CH: gypsum plaster board, at plant 7 Glass fibre fabric 0,1 120 RER: glass fibre, at plant 4 Roof Structural timber 10 120 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Bitumen membrane 7,6 60 RER: bitumen sealing, V60, at plant 9 Plast foil 0,2 60 RER: polyethylene, LDPE, granulate, at plant 5 Mineral wool 14 120 CH: glass wool mat, at plant 4 OSB plates 14 60 RER: oriented strand board, at plant 8 Tiles 69 60 RER: roof tile, at plant 4 Plaster 6,5 40 CH: gypsum plaster board, at plant 7 Doors and windows Glazing, thermo (3- layer) 5,5 25 RER: glazing, triple (3-IV), U<0.5W/m2K, at plant 10 Window frame, alu 0,9 50 RER: window frame, aluminium, U=1.6W/m2K, at plant 11 Window sill, wood 1,4 50 RER: window frame, wood, U=1.5W/m2K, at 8
  • 89. APPENDIX  B:  INVENTORY  LIST   STANDARD  HOUSE       5/22 plant Wooden doors 3,7 60 RER: door, inner, wood, at plant 8 Floors and surfaces Paint, waterbased 0,3 10 RER: alkyd paint, white, 60% in H2O, at plant 12 Rug 0,7 30 GLO: textile, woven cotten, at plant 13 Tiles, glazed 0,8 60 CH: ceramic tils, at regional storage 4 Wodden floors 1,3 60 RER: sawn timber, softwood, planed, kiln dried, at plant 8 Tile adhesive 2,2 30 CH: adhesive mortar, at plant 18 Tiles, non-glazed 5,0 60 CH: ceramic tiles, at regional storage 4 Installations Sanitary ceramics 0,5 40 CH: sanitary ceramics, at regional storage 4 Hot water tank 0,3 30 CH: hot water tank 600l, at plant 3 Circulation pump 0,04 20 CH: pump 40W, at plant 3 Ventilation unit 0,8 25 CH: ventilation system, decentralized, 6 x 120 m3/h, steel ducts, without GHE 3 Water pipes 0,1 60 RER: steel, low-alloyed, at plant 3 Heaters 1,8 30 RER: steel, low-alloyed, at plant 3
  • 90.   APPENDIX  C:  END  OF  LIFE  FLOWS   6/22   APPENDIX C: END OF LIFE FLOWS EoL flow EoL dataset(s) Next product system – Avoided processShare of mass Dataset 1 100% CH: Disposal, concrete, 5% water, to inert material landfill 2 100% CH: disposal, expanded polystyrene, 5% water, to municipal incineration CH: heat, biowaste, at waste incineration plant, allocation price 3 CH: disposal, building, reinforcement steel, to recycling RER: steel, low-alloyed, at plant CH: disposal, steel, 0% water, to inert material landfill 4 100% Disposal inert material, 0% water, to inert material landfill 5 100% CH: disposal polyethylene, 0,4% water, to municipal incineration CH: heat, biowaste, at waste incineration plant, allocation price 6 100% CH: disposal, cement, hydrated, 0% water, to residual material landfill 7 CH: disposal, building, plaster-cardboard sandwich, to sorting plant CH: disposal, building, plaster-cardboard, sandwich, to recycling CH: Base plaster, at plant CH: disposal, inert material, 5% water, to inert material landfill 8 100% CH: disposal, wood untreated, 20% water, to municipal incineration CH: heat, biowaste, at waste incineration plant, allocation price 9 100% CH: disposal, building, bitumen sheet, to final disposal 10 CH: disposal, building, glazing, 3-IV, U<0,5W/m2K, to final disposal RER: flat glass, uncoated, at plant 11 CH: disposal, building, reinforcement steel, to recycling RER: aluminium alloy, AlMg3, at plant CH: disposal, aluminium 0% water, to sanitary landfill 12 100% CH: disposal, building, paint on wood, to final disposal 13 CH: disposal, textiles, soiled, 25% water, to CH: heat, biowaste, at waste
  • 91. APPENDIX  C:  END  OF  LIFE  FLOWS       7/22 municipal incineration incineration plant, allocation price 14 CH: heat, biowaste, at waste incineration plant, allocation price 15 RER: polyetyhylene terephthalate, granulate, bottle grade, at plant 16 CH: disposal, PE sealing sheet, 4% water, to municipal incineration 17 CH: disposal, building, glass sheet, to final disposal RER: flat glass, uncoated, at plant 18 No EoL flow
  • 92.   APPENDIX  D:  MATERIAL  PROPERTIES   8/22   APPENDIX D: MATERIAL PROPERTIES Recycling rates (Denmark) Material Recycling rate Reference Plastic (foil) 34,7% www.epro-plasticsrecycling.org Plaster 80% www.ecoinnovation.dk Steel 97,5% www.recycle-steel.org Aluminium 90% www.alueurope.eu Building glazing 10% Most building glazing is landfilled according to: www.glassforeurope.com . Here 90% is assumed as “most”. Material properties, Density Material Density [kg/m3 ] Concrete, normal 2200 Concrete, aerated 1000 Structural timber 450 OSB plates 680 Rug 42 Richlite composite 1213
  • 93. APPENDIX  F:  ENVIRONMENTAL   IMPACTS       9/22 APPENDIX F: ENVIRONMENTAL IMPACTS Climate change Ozone depletion The greenhouse gasses are allows the short waved radiation from the sun to enter the atmosphere but keeps the long waved radiation from the earth from leaving. In that way they create a green house effect by trapping the heat in the atmosphere. The GWP varies with the greenhouse gasses, and it is therefore expressed relative to the GWP of carbon dioxide in CO2 equivalent but also within a specific time horizon since the lifetime of the gases in the atmosphere also differs. The ozone layer plays an important role for life on earth shielding it from UV-A and UV-B radiations, and thereby preventing an overheating of the earth’s surfaces as well as protects flora and fauna. A number of free radical catalysts such as nitric oxide, chlorine and atomic bromine causes a depletion of the ozone layer with consequences such as increase in tumour formations in human and animals as wells as disturbances in the photosynthesis. Human activities increase the concentrations of these free radicals by releasing man-made compounds such as CFC’s and bromofluorocarbons. Eutrophication Terrestrial acidification Eutrophication can be aquatic or terrestrial and refers to an enrichment of nutrients in a specific area. Aquatic eutrophication can cause accelerated algae growth, which over time can lead to fish dying as well as anaerobic decomposition, having severe negative impact on eco-systems. A contribution to eutrophication comes from agricultural fertilizers, air pollutants as well as wastewater. When air pollutants such as sulfur and nitrogen compounds reacts with water, sulfuric and nitric acids are created, and when the acid reaches ground level it causes damaging effects to flora and fauna. Acidic soil for instance dissolves nutrients faster causing an increased leaching of nutrients. Acidification is regarded as a regional effect, and can also have degrading effect on buildings. Photochemical ozone formation When ozone is created near ground level of the earth it is often referred to as summer-smog. It can cause negative health effects especially related to the respiratory system but can also have a negative impact on flora and fauna. Human activities affect the creation of ground level ozone mainly through incomplete combustions of fossil fuels.
  • 94.   APPENDIX  G:  PROLONGED  LIFETIME   10/22   APPENDIX G: PROLONGED LIFETIME Standard house (excluding use phase energy) Annual impacts, Standard house – 128m2 , building lifetime (varies), excl. use phase energy 50yr 120yr Terrestrial acidification (AP) 83 56 mole H+ eq. Water depletion 23 13 m3 Land Use Erosion - - ton eroded soil Biodiversity 357 220 m2 *year Climate change (GWP) 1048 595 kg CO2 eq. Ozone depletion (ODP) 0,0001 0,0001 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,2 0,1 kg P eq. Marine 0,2 0,1 kg N eq. Terrestrial 41 26 mole N eq. Photochemical oxidant formation (POCP) 3 2 kg NMVOC Freshwater ecotoxicity 1206 741 PAF*m3 *day IN,B 50yr 120yr Terrestrial acidifiation 12% 8% Water depletion 26% 15% Land use Erosion - - Biodiv. 8% 5% Climate change Temp. 365% 207% Rad. for. 690% 391% Ozone depletion 0,4% 0,2% Eutrophi- cation Freshwat. 163% 109% Marine 2% 2% Terrest. 5% 3% Ozone formation 24% 14% Freshwater ecotoxicity 41% 25% Comments: Only impact from materials and construction is included. 128m2 heated area. Br2015 50 year lifetime 120 year lifetime
  • 95. APPENDIX  G:  PROLONGED  LIFETIME       11/22 Upcycle house Annual impacts, Upcycle house – 128m2 , building lifetime (varies), excl. use phase energy 50yr 120yr Terrestrial acidification (AP) 59 48 mole H+ eq. Water depletion 11 7 m3 Land Use Erosion - - ton eroded soil Biodiversity 216 172 m2 *year Climate change (GWP) 361 218 kg CO2 eq. Ozone depletion (ODP) 0,0000 3 0,0000 2 kg CPC-11 eq. Eutrophication (EP) Freshwater 0,12 0,09 kg P eq. Marine 0,11 0,08 kg N eq. Terrestrial 25 21 mole N eq. Photochemical oxidant formation (POCP) 3 59 4 8 kg NMVOC Freshwater ecotoxicity 11 7 PAF*m3 *day I/C 50yr 120yr Terrestrial acidifiation 9% 7% Water depletion 13% 8% Land use Erosion - - Biodiv. 5% 4% Climate change Temp. 126% 76% Rad. for. 237% 143% Ozone depletion 0,1% 0,1% Eutrophi- cation Freshwat. 93% 67% Marine 1,2% 0,9% Terrest. 3% 3% Ozone formation 14% 10% Freshwater ecotoxicity 35% 24% Comments: Onlys impact from materials and construction is included. 128m2 heated area. Br2015 50 year lifetime 120 year lifetime
  • 96.   APPENDIX  H:  SENSITIVITY  -­‐  SUB  CATEGORIES   12/22   APPENDIX H: SENSITIVITY - SUB CATEGORIES In the allocation scenarios a range of assumptions are made when allocating the subcategories to the dwelling, i.e 30% of household electricity is used for operation of the dwelling when allocating according to economic value. Therefor a sensitivity analysis of influence of these assumptions on the final result was carried out. Many subcategories were assumed 100% allocated to the dwelling, i.e 100% of rentals is allocated to the dwelling, and these are not included in the sensitivity analysis, only assumptions where less than 100% of a subcategory is allocated are. In allocation scenario C, the EIPRO study, all relevant subcategories are allocated 100% to the dwelling, due to the background studies initial allocation work as earlier described. The final results showed only little sensitivity towards the assumptions made in the allocation of subcategories. For the global warming potential this meant a deviation of +/- 1% on the final result when deviating the allocation of subcategories with +/- 20%. Allocation scenario -20% in sub.cat - +20% in sub.cat Economic value A. Eurostat 110 111 112 Environmental pressure B. EEA 112 113 115 C. EC - 43 -
  • 97. APPENDIX  I:  MODEL  VALIDATION       13/22 APPENDIX I: MODEL VALIDATION 1.1.1 Alternation of models To validate the models, a number of lifecycle stages need to be excluded, since they are not included in the method used by SBI. SBI divides the buildings life cycle into three main stages, production phase, use phase and end of life. From Table 1 similarities and differences between the analysis carried out by SBI and the current build-up in Gabi can be seen. In order to compare the results and validate the model, the processes involving construction phase (energy, spill and transport from gate to site), land use and conversion, repair in use phase, demolition of the building and transport from site to disposal has to be excluded from the model. Table 1 Processes involved in the building lifecycle in respectively the SBI analysis and the current project Production phase Use phase End of life SBI Own Model SBI Own Model SBI Own Model Extraction X X Maintenance Demolition (X) Transport X X Repair (X) Transport X Production X X Replacement X X Waste handling X X Construction X Modifications Recycling X X Landconversion X Energy X X Landfill X X Water Land use X A few exceptions are made regarding repair and demolition, which is not fully excluded from the models. In the model the materials used for repair are assumed to 1% of the initial mass of individual selected exposed materials (such as mortar, brick and rooftiles). The impacts from repair will therefore be insignificant, and
  • 98.   APPENDIX  I:  MODEL  VALIDATION   14/22   since the repair part is not parameterized in the model it will not be excluded in the validation process. When it comes to demolition this is included in the EoL processes in the Ecoinvent database that directly refers to the building, ie. “Disposal, building, reinforcing steel”. In all other processes where a dataset refereeing directly to the building have not been available, the demolition is not added separately. The impacts from demolition are therefor not possible to exclude from the model, but are in line with the impact from repair expected to have negligible influence on the end results. When it comes to the end of life flows for the different materials differences are also seen between the SBI method and the current model. As opposed to the current model the SBI assessment does not include recycling potential of plaster and reinforcement steel, so recycling rates are set to 0% in these flows causing 100% of the EoL flow to landfill. Further more there are some materials where the SBI assessment does not include an EoL flow, and the EoL flow in the model is therefore set to 0. This concerns materials as the bitumen membrane in the roof of the Reference house, all glazing used as well as paint. The GaBi model of the Reference house is adjusted to include only the processes included in the SBI analysis as described in 1.1.1. For the project model this includes, inter alia, deactivation of surtain EoL flows such as the bitumen membrane in the roof as well as building glazing. Further more the building lifetime is adjusted to 120 years instead of the initial 50 years, since the SBI report involving the reference house states the resulting global warming impact based on a 120-year period. 1.1.2 Sources of errors The inventory lists are obtained from SBI, and the inventory basis is therefore identical when comes to mass and material types, but although the indata for the models are based on the same amount and material types as the SBI models, there still remain a number of assumptions, which can all lead to variations in the resulting impacts. Some of the datasets used demands conversion from mass to area or quantity, and densities used for this are based on general assumptions. Further more assumptions on recycling rates are made aiming at a recycling rate representative for the specific material in the Danish construction sector when possible. When it comes to the Upcycle house, the upcycle factors applied are in accordance with the inventory lists of SBI. Though with exception of the upcycle factor of old bricks, which do not appear in the report, but is assumed to be 0,5. The primary data source for the current project is the Ecoinvent database 2.2 where the SBI assessment is primarily based on the ESUCO database. Due to differences between the databases, this will lead to natural
  • 99. APPENDIX  I:  MODEL  VALIDATION       15/22 deviations in the output results. Furthermore there are differences in the specific processes in the databases, why assumptions have been made regarding which Ecoinvent processes comes closest to the ESUCO process used in the SBI model. EPD’s have also been used as data source for some materials. In the current model the EPD’s have only been used to identify the material composition and not the resulting impacts. This can off course also lead to deviations, but was assumed to create the most accurate output result since the evaluation method of the EPD’s varies.
  • 100.   APPENDIX  J:  SUB-­‐CAT.  EXPENSES  CP04-­‐05   16/22   APPENDIX J: SUB-CAT. EXPENSES CP04-05 Distribution of expenses in the sub-categories of CP04-05. Green marks categories allocated to the dwelling. Share  of  Category  [%] %  allocated  to   dwelling CP04 CP041  -­‐  Actual  rentals  for  housing CP0411  -­‐  Actual  rentals  paid  by  tenants 19,3 1,0 CP0412  -­‐  Other  actual  rentals 0,5 CP042  -­‐  Impited  rentals  for  housing CP0421  -­‐  Impted  rentals  of  owner-­‐ occupiers 51,1 1,0 CP0422  -­‐  Other  imputed  rentals 2,5 CP043  -­‐  Maintenance  and  epair  of  the   dwelling CP0431  -­‐  Materials  for  the  maintainance 3,1 CP0432  -­‐  Services  for  the  maintenance   3,2 CP044  -­‐  Water  supply  and  miscellaneous CP0441  Water  supplu 2,4 CP0442  -­‐  Refuse  collection 1,4 CP0443  -­‐  Sewerage  collection 0,1 CP0444  ther  services  relating  to  the   dwelling 1,7 CP045  -­‐  Electricity,  gas  and  other  fuels CP0451  -­‐  Electricity 7,1 0,3 CP0452  -­‐  Gas 3,9 1,0 CP0453  -­‐  Liquid  fuels 1,9 1,0 CP0454  -­‐  Solid  fuels 0,6 1,0 CP0455  -­‐  Heat  energy 1,4 1,0 Total  allocation  of  CP04 80,1 CP05 CP051  -­‐  Furniture  and  furnishings,  carpets
  • 101. APPENDIX  J:  SUB-­‐CAT.  EXPENSES  CP04-­‐ 05       17/22 CP0511  -­‐  Furniture  and  furnishings 36,5 CP0512  -­‐  Carpets  and  other  floor  coverings 5,4 0,4 CP0513  -­‐  Repair  of  furniture,  furnishings   and  floor 0,9 CP052  -­‐  Household  textiles CP053  -­‐  Household  appliances CP0531  -­‐  Major  household  appliances 10,1 0,4 CP0532  -­‐  Small  electric  household   appliances 1,4 CP053  -­‐  Repair  of  household  appliances 2,0 CP054  Glassware,  tableware  and  utensils 6,1 CP055  -­‐  Tools  and  equipment  for  house,   garden 7,0 CP0551  -­‐  Major  tools  and  equipment 1,5 CP0552  -­‐  Small  tools  and  miscellaneous  acc. 5,5 CP056  -­‐  Goods  and  services  for  routine 22,9 CP0561  Non-­‐durable  household  goods 14,7 CP0562  -­‐  Domestic  services  and  household   ser. 8,2 Total  allocation  of  CP05 6,2
  • 102.   APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)   18/22   APPENDIX K: SUB-CAT. EMISSSIONS CP04-05 (EIPRO) Distribution of environmental pressure in the sub-categories of CP04-05 in four impact categories. Green marks categories allocated to the dwelling. Global  warmning  potential   CP04-­‐05  -­‐  Housing  etc.   CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 4,7 19,9 A31 New  residential  1unit  structure,  nonfarm 3,2 13,6 A333 (washing  with)  household  laundry  equipment 2,4 10,2 A33 New  additions  &  alterations,  nonfarm,  construction 1,8 7,6 A332 (Use  of)  household  refriferators  and  freezers 1,8 7,6 A337 (use  of)  electric  lamp  bulbs  and  tubes 1,2 5,1 A331 (use  of  )  household  cooking  equipment 1 4,2 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,7 3,0 A413 Water  supply  and  seweage  systems 0,7 3,0 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,7 3,0 A393 Non-­‐durable  household  goods 0,5 2,1 A106 Carpets  and  rugs 0,3 1,3 A139 Wod  household  furniture,  except  upholstered 0,3 1,3 A149 Parittions  and  fixtures,  except  wood 0,3 1,3 A201 Miscellaneous  plastic  products,  n.e.c 0,3 1,3 A437 Miscellaneous  equipment  rental  and  leasing 0,2 0,8 A117 Housefurnishings,  n.e.c 0,2 0,8 A439 Other  buisness  services 0,2 0,8 A335 (use  of)  household  vacuum  cleaners 0,2 0,8 A142 Upholsteres  household  furniture 0,2 0,8 A334 (use  of)  electric  housewares  and  fans 0,2 0,8 A17 Forestry  proudcts 0,2 0,8 A25 Crude  petreoleum  and  natural  gas 0,2 0,8 A429 Electrical  repair  shops 0,1 0,4
  • 103. APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS   CP04-­‐05    (EIPRO)       19/22 A144 Mattresses  and  bedsprings 0,1 0,4 A430 Watch,  clock,  jewlry  and  furniture  repair 0,1 0,4 A123 Fabricated  textile  products,  n.e.c 0,1 0,4 A148 Woodd    partitions  and  fixtures 0,1 0,4 A121 Automotive  and  apparel  trimmings 0,1 0,4 63 Other  categories,  total 1,5 6,4 SUM  of  allocation  to  building 10,9 47,0 Photochemical  oxidation CP04-­‐05  -­‐  Housing  etc. CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 3,8 17,3 A31 New  residential  1unit  structure,  nonfarm 3,8 17,3 A333 (washing  with)  household  laundry  equipment 1,1 5,0 A33 New  additions  &  alterations,  nonfarm,  construction 2,1 9,5 A332 (Use  of)  household  refriferators  and  freezers 0,8 3,6 A337 (use  of)  electric  lamp  bulbs  and  tubes 0,4 1,8 A331 (use  of  )  household  cooking  equipment 0,6 2,7 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,9 4,1 A413 Water  supply  and  seweage  systems 0,6 2,7 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,7 3,2 A393 Non-­‐durable  household  goods 0,8 3,6 A106 Carpets  and  rugs 0,6 2,7 A139 Wod  household  furniture,  except  upholstered 0,4 1,8 A149 Parittions  and  fixtures,  except  wood 0,3 1,4 A201 Miscellaneous  plastic  products,  n.e.c 0,5 2,3 A437 Miscellaneous  equipment  rental  and  leasing 0,3 1,4 A117 Housefurnishings,  n.e.c 0,4 1,8 A439 Other  buisness  services 0,3 1,4 A335 (use  of)  household  vacuum  cleaners 0,2 0,9 A142 Upholsteres  household  furniture 0,3 1,4 A334 (use  of)  electric  housewares  and  fans 0,1 0,5
  • 104.   APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)   20/22   A17 Forestry  proudcts 0,2 0,9 A25 Crude  petreoleum  and  natural  gas -­‐ -­‐ A429 Electrical  repair  shops 0,2 0,9 A144 Mattresses  and  bedsprings 0,2 0,9 A430 Watch,  clock,  jewlry  and  furniture  repair 0,2 0,9 A123 Fabricated  textile  products,  n.e.c 0,2 0,9 A148 Woodd    partitions  and  fixtures 0,1 0,5 A121 Automotive  and  apparel  trimmings 0,2 0,9 A116 Curtains  and  drapiers 0,1 0,5 A143 Matal  household  furniture 0,1 0,5 A145 Wood  office  furniture 0,1 0,5 A32 New  residential  2-­‐4unit  structures,  nonfarm 0,1 0,5 A151 Furniture  and  fixtures,  nec 0,1 0,5 59 Other  categories,  total 1,2 5,5 SUM  of  allocation  to  building 11 50 Eutrophication       CP04-­‐05  -­‐  Housing  etc.       CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 1 10,1 A31 New  residential  1unit  structure,  nonfarm 1,2 12,1 A333 (washing  with)  household  laundry  equipment 0,6 6,1 A33 New  additions  &  alterations,  nonfarm,  construction 0,7 7,1 A332 (Use  of)  household  refriferators  and  freezers 0,4 4,0 A337 (use  of)  electric  lamp  bulbs  and  tubes 0,3 3,0 A331 (use  of  )  household  cooking  equipment 0,2 2,0 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,3 3,0 A413 Water  supply  and  seweage  systems 0,2 2,0 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,2 2,0 A393 Non-­‐durable  household  goods 0,8 8,1 A106 Carpets  and  rugs 0,7 7,1 A139 Wod  household  furniture,  except  upholstered 0,1 1,0
  • 105. APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS   CP04-­‐05    (EIPRO)       21/22 A149 Parittions  and  fixtures,  except  wood 0,1 1,0 A201 Miscellaneous  plastic  products,  n.e.c 0,1 1,0 A437 Miscellaneous  equipment  rental  and  leasing 0,1 1,0 A117 Housefurnishings,  n.e.c 0,7 7,1 A439 Other  buisness  services 0,1 1,0 A335 (use  of)  household  vacuum  cleaners 0,1 1,0 A142 Upholsteres  household  furniture 0,3 3,0 A334 (use  of)  electric  housewares  and  fans 0,1 1,0 A17 Forestry  proudcts 0,2 2,0 A25 Crude  petreoleum  and  natural  gas -­‐ -­‐ A429 Electrical  repair  shops -­‐ -­‐ A144 Mattresses  and  bedsprings 0,1 1,0 A430 Watch,  clock,  jewlry  and  furniture  repair 0,1 1,0 A123 Fabricated  textile  products,  n.e.c 0,2 2,0 A148 Woodd    partitions  and  fixtures -­‐ -­‐ A121 Automotive  and  apparel  trimmings 0,2 2,0 A116 Curtains  and  drapiers 0,2 2,0 A182 Chemicals  and  chemical  preparations,  n.e.c 0,1 1,0 A120 Pleating  and  stiching 0,1 1,0 63 Other  categories,  total 0,4 4,0 SUM  of  allocation  to  building 3,4 34,3 Acidification CP04-­‐05  -­‐  Housing  etc. CEDA  cat. Name %-­‐of  total   household %  of   category A257 (Heating  with)  heating  equipment,  except  electric  and   warm  air  furnaces 2,7 10,5 A31 New  residential  1unit  structure,  nonfarm 3 11,7 A333 (washing  with)  household  laundry  equipment 4 15,6 A33 New  additions  &  alterations,  nonfarm,  construction 1,8 7,0 A332 (Use  of)  household  refriferators  and  freezers 3 11,7 A337 (use  of)  electric  lamp  bulbs  and  tubes 2,2 8,6 A331 (use  of  )  household  cooking  equipment 1,5 5,8 A42 Mainenance  and  repair  of  farm  and  nonfarm   residential  structues 0,7 2,7
  • 106.   APPENDIX  K:  SUB-­‐CAT.  EMISSSIONS  CP04-­‐05    (EIPRO)   22/22   A413 Water  supply  and  seweage  systems 0,6 2,3 A34 New  residential  garden  and  high-­‐rise  apartments   constructions 0,7 2,7 A393 Non-­‐durable  household  goods 0,5 1,9 A106 Carpets  and  rugs 0,3 1,2 A139 Wod  household  furniture,  except  upholstered 0,3 1,2 A149 Parittions  and  fixtures,  except  wood 0,3 1,2 A201 Miscellaneous  plastic  products,  n.e.c 0,2 0,8 A437 Miscellaneous  equipment  rental  and  leasing 0,2 0,8 A117 Housefurnishings,  n.e.c 0,2 0,8 A439 Other  buisness  services 0,2 0,8 A335 (use  of)  household  vacuum  cleaners 0,3 1,2 A142 Upholsteres  household  furniture 0,2 0,8 A334 (use  of)  electric  housewares  and  fans 0,3 1,2 A17 Forestry  proudcts 0,2 0,8 A25 Crude  petreoleum  and  natural  gas -­‐ -­‐ A429 Electrical  repair  shops 0,1 0,4 A144 Mattresses  and  bedsprings 0,1 0,4 A430 Watch,  clock,  jewlry  and  furniture  repair 0,1 0,4 A123 Fabricated  textile  products,  n.e.c -­‐ -­‐ A148 Woodd    partitions  and  fixtures 0,1 0,4 A121 Automotive  and  apparel  trimmings 0,1 0,4 Fabricated  textile  proudcts 0,1 0,4 65 Other  categories,  total 1,7 6,6 SUM  of  allocation  to  building 8,8 34,2   Average  of  previous  four  categories   SUM  of  allocation  to  building 8,5 41,4