EPA/600/R-10/183F. Concludes that the extent of negative impacsts to date are limited in magnitude and are primarily associated with the intensification of corn production.

In December 2007, the Congress expanded the renewable fuel standard (RFS), which requires rising use of ethanol and other biofuels, from 9 billion gallons in 2008 to 36 billion gallons in 2022. To meet the RFS, the Departments of Agriculture (USDA) and Energy (DOE) are developing advanced biofuels that use cellulosic feedstocks, such as corn stover and switchgrass. The Environmental Protection Agency (EPA) administers the RFS. This report examines, among other things, (1) the effects of increased biofuels production on U.S. agriculture, environment, and greenhouse gas emissions; (2) federal support for domestic biofuels production; and (3) key challenges in meeting the RFS. GAO extensively reviewed scientific studies, interviewed experts and agency officials, and visited five DOE and USDA laboratories. GAO suggests that the Congress consider requiring EPA to develop a strategy to assess lifecycle environmental effects of increased biofuels production and whether revisions are needed to the VEETC. GAO also recommends that EPA, DOE, and USDA develop a coordinated approach for addressing uncertainties in lifecycle greenhouse gas analysis and give priority to R & D that addresses future blend wall issues. DOE, USDA, and EPA generally agreed with the recommendations.