Jane Van Ryan
Posted July 22, 2009
Ethanol, which in the United States is generally made from corn, has been an important part of the gasoline supply for several years. In many regions of the country and in certain seasons, it accounts for as much as 10 percent of the gasoline fuel supply.
At levels of 10 percent or lower, ethanol is a valuable gasoline additive that increases octane and can be used in all motor vehicles and virtually all engines. But above levels of 10 percent, ethanol raises fuel oxygen content well outside the range for which U.S. vehicles and engines have been designed.
Use the player below to listen to an EnergyTomorrow Radio episode about the use of ethanol in gasoline.
An ethanol advocacy group called Growth Energy is seeking a waiver under the Clean Air Act to increase the level of ethanol in gasoline to 15 percent. According to a published report, Growth Energy says the 10 percent limit on ethanol blends is making it difficult for the nation to meet the federal renewable fuel mandates requiring the United States to produce 36 billion gallons of renewable fuels by 2022. It should be noted, however, that the E10 blend wall (the point at which all gasoline is blended with 10 percent ethanol) will not be reached until the end of 2013.
Farm groups favor the move to E15, but other industries and trade groups oppose it. The Alliance of Automobile Manufacturers says the use of E15 could void automobile warranties. API, which hosts this blog, says additional research is needed to ensure that fuel blends containing more than 10 percent ethanol can be used safely. In a letter to the Environmental Protection Agency (EPA), API said, "...thorough vehicle and engine studies that develop robust, supportive data are needed to ensure that adverse impacts are avoided and the consumer is adequately protected. The oil and natural gas industry needs a level of confidence in the data that would allow our brands to stand behind a new fuel."
API is working with the automakers, U.S. Department of Energy, the EPA, small engine manufacturers, ethanol producers and others on a multi-year, multi-million dollar research effort on mid-level ethanol blends. API believes it would be premature to approve any waiver request until this research is finished and the results are thoroughly evaluated.
The EPA must make a decision on whether to increase the allowed ethanol level by December 1.
Update on July 23, 2009: Read more about ethanol and gasoline blends in a API statement released today.
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