Calculation of Lifecycle Greenhouse Gas Emissions for the Renewable Fuel Standard (RFS)

Brent D. Yacobucci
Specialist in Energy and Environmental Policy

Kelsi Bracmort
Analyst in Agricultural Conservation and Natural Resources Policy

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.


Date of Report: March 12, 2010
Number of Pages: 22
Order Number: R40460
Price: $29.95

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