Renewable Fuel Standard: Low Expected Production Volumes Make It Unlikely That Advanced Biofuels Can Meet Increasing Targets, Report to the Chairman, Subcommittee on Regulatory Affairs and Federal Management, Committee on Homeland Security and Governmental Affairs, U.S. Senate [open pdf - 5MB]
From the Highlights: "The RFS [Renewable Fuel Standard] generally mandates that domestic transportation fuels be blended with increasing volumes of biofuels through 2022, with the goals of reducing greenhouse gas emissions and expanding the nation's renewable fuels sector while reducing reliance on imported oil. Blending of conventional renewable fuels, primarily ethanol derived from corn starch which is required to reduce greenhouse gas emissions by 20 percent compared with petroleum-based fuels, has nearly reached the maximum called for under the RFS. Further growth in renewable fuels is to come from advanced biofuels, which must reduce life-cycle greenhouse gas emissions by at least 50 percent compared with petroleum-based fuels to qualify under the RFS. However, production of advanced biofuels has not kept pace with statutory targets. To promote the development and commercialization of advanced biofuels, the federal government has supported R&D [Research and Development] efforts for bio fuels since the 1970s."