The federal Renewable Fuel Standard was enacted as part of the Energy Policy Act in 2005. It was revised to include more feedstocks and prioritize GHG reductions as part of the Energy Independence and Security Act of 2007. Consequently, it now includes mandatory thresholds for GHG reductions from qualifying biofuels based on life-cycle analysis, effectively shifting production away from corn-based biofuels. Life-cycle analysis (conducted using the GREET methodology) requires an assessment of biofuels’ life-cycle emissions from three distinct fuel pathways: feedstock production and transport; fuel production and distribution; and end-use tailpipe emissions.