The EPA is evaluating the impact higher blends of ethanol in regular gasoline would have on engine performance and air emissions.
Growth Energy, an ethanol industry group, has submitted a waiver request to the U.S. Environmental Protection Agency (EPA) asking that the limit for blending ethanol into gasoline be raised from 10 percent to 15 percent.
Currently, regular blends of gasoline are allowed to contain as much as 10 percent ethanol, a blend called E10, and this constitutes the primary market for ethanol fuel in the United States. Flex-fuel vehicles can also burn an ethanol-rich blend called E85, which contains 85 percent ethanol, though the market for E85 is relatively small.
Meanwhile, the federal Renewable Fuel Standard (RFS) requires that an increasing amount of renewable fuel be sold in the United States each year, and that becomes a challenge when gasoline consumption drops. For 2009, the EPA requires most refiners, importers and blenders of gasoline to displace 10.21 percent of their gasoline with renewable fuels such as ethanol, up from only 7.76 percent in 2008, in part because of a drop in gasoline consumption. That requirement is already pushing up against the “blend wall” — that is, the maximum amount of ethanol that can be sold in the form of E10 and E85.
To give the EPA more leeway to meet the RFS requirement, the U.S. Department of Energy (DOE) and other agencies have been examining the possibility of allowing higher blends of ethanol in regular gasoline, which raises concerns about the impacts of higher blends on engine performance and air emissions. To address these concerns, DOE is conducting an ongoing test program to evaluate the potential impact of higher ethanol blends, including gasoline blends containing 15 percent and 20 percent ethanol. DOE is working with the EPA, industry, and other research groups to examine all the ramifications of increased ethanol blends.
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