The letter urges the Senate Finance Committee to continue supporting renewable energy through tax policy, which has been crucial to the growth of industries like wind and solar. It summarizes that renewable sources made up over 50% of new US power in 2014, with technologies like wind and solar experiencing major cost reductions thanks to tax credits. However, uncertainty around the extension of credits like the PTC and ITC threatens continued growth. The letter argues that permanent, consistent tax policies are needed to provide long-term market signals and make renewable energy widely available to businesses and consumers, in the same way policies have supported oil and gas.