	Introduction

On August 8, 2005, President Bush signed the Energy Policy Act of 2005 (EPAct 2005; P.L. 109-58 ). The Energy Independence and Security Act of 2007 (EISA; P.L. 110-140 ), signed by President Bush on December 19, 2007, significantly expanded the RFS to include diesel fuel, requiring the use of 9.0 billion gallons of renewable fuel in 2008, increasing to 36 billion gallons in 2022. EISA also requires an increasing amount of the mandate be met with "advanced biofuels"—biofuels produced from feedstocks other than corn starch and with 50% lower lifecycle greenhouse gas emissions than petroleum fuels. Within the advanced biofuel mandate, there are specific carve-outs for cellulosic biofuels and biomass-based diesel substitutes (e.g., biodiesel). Under EPAct 2005, the Environmental Protection Agency (EPA) released a final rulemaking for 2007 and beyond. Because of the changes in the RFS from P.L. To classify biofuels under the RFS, EPA must calculate the lifecycle emissions of each fuel relative to gasoline or diesel fuel. Debate is ongoing on how each factor in the biofuels lifecycle should be addressed, and the issues surrounding direct and indirect land use are particularly controversial. However, EPA's proposed methodology was criticized by many stakeholders. In response to comments by peer reviewers and the public, EPA modified its methodology to reflect some of those criticisms. In the final rule, all assessed biofuels met the threshold requirements for their category. Further, EISA does not specify the methodology for EPA to make its determinations on lifecycle emissions. EPA's methodology in the final rule is described in a subsequent section of this report. Land Use Change Estimations for the Lifecycle Emissions Analysis

On May 26, 2009, EPA issued a Notice of Proposed Rulemaking (NPRM) to issue new RFS regulations. The NPRM included suggested methodology for a lifecycle analysis of significant greenhouse gas emissions—both direct and indirect—from the production of renewable fuels. The following paragraphs summarize the major points of the methodology put forth by EPA in its Notice of Proposed Rulemaking to account for land use change in the LCA, as well as key changes between the NPRM and the final rule issued on February 3, 2010. California's Low Carbon Fuel Standard (LCFS)

On January 12, 2009, the state of California finalized regulations for a state low carbon fuel standard (LCFS). The LCFS requires increasing reductions in the average lifecycle emissions of most transportation fuels. Oversight

Definitions for various biofuels under the RFS could directly affect the supply of eligible fuels in the program. The specifics of any new legislation on fuel carbon emissions would determine how that legislation interacts with the RFS requirements.
The Energy Independence and Security Act of 2007 (EISA; P.L. 110-140) significantly expanded the renewable fuel standard (RFS) established in the Energy Policy Act of 2005 (EPAct 2005; P.L. 109-58). The RFS requires the use of 9.0 billion gallons of renewable fuel in 2008, increasing to 36 billion gallons in 2022. Further, EISA requires an increasing amount of the mandate be met with "advanced biofuels"—biofuels produced from feedstocks other than corn starch and with 50% lower lifecycle greenhouse gas emissions than petroleum fuels. Within the advanced biofuel mandate, there are specific carve-outs for cellulosic biofuels and biomass-based diesel substitutes (e.g., biodiesel).
To classify biofuels under the RFS, the Environmental Protection Agency (EPA) must calculate the lifecycle emissions of each fuel relative to gasoline or diesel fuel. Lifecycle emissions include emissions from all stages of fuel production and use ("well-to-wheels"), as well as both direct and indirect changes in land use from farming crops to produce biofuels. Debate is ongoing on how each factor in the biofuels lifecycle should be addressed, and the issues surrounding direct and indirect land use are particularly controversial. How EPA resolves those issues will affect the role each fuel plays in the RFS.
EPA issued a Notice of Proposed Rulemaking on May 26, 2009, for the RFS with suggested methodology for the lifecycle emissions analysis. EPA issued a final rule on February 3, 2010. The final rule includes EPA's methodology for determining lifecycle emissions, as well as the agency's estimates for the emissions from various fuels. In its proposed rule, EPA found that many fuel pathways did not meet the threshold requirements in EISA. However, its methodology was criticized by biofuels supporters. In the final rule, EPA modified its methodology to reflect some of those comments. However, some biofuels opponents counter that the final rules went too far in the opposite direction. In most cases, estimated emissions decreased (i.e., emissions reductions increased), leading to more favorable treatment of biofuels in the final rule.
Because of the ongoing debate on the lifecycle emissions from biofuels, including finalized regulations by the state of California for a state low carbon fuel standard (LCFS) in January 2009, there is growing congressional interest in the topic. Congressional action could take the form of oversight of EPA's rulemaking process, or could result in legislation to amend the EISA RFS provisions. Further, related legislative and regulatory efforts on climate change policy and/or a low-carbon fuel standard would likely lead to interactions between those policies and the lifecycle determinations under the RFS.