The Energy Independence and Security Act (EISA) of 2007 was an omnibus energy policy law designed to move the United States toward greater energy security and independence.1 A key provision of EISA modified the Renewable Fuel Standard (RFS) which requires the nation to increase the volume of renewable fuel blended into transportation fuels from 7.5 billion gallons by 2012 to 36 billion gallons by 2022. Ethanol is the most widely used renewable fuel, and increasing the ethanol content in gasoline to 15% offers a means of getting significantly closer to the 36 billion gallon goal. In March 2009, Growth Energy (a coalition of ethanol producers and supporters) requested a waiver from the United States Environmental Protection Agency (EPA) to allow the use of 15% ethanol in gasoline.2 In response the US EPA granted two partial waivers that allow (but do not require) E15 in 2001 and newer light-duty vehicles. Prior to the waiver being granted, uncertainties arose as to whether the additional fuel ethanol (from 10% to 15%), would cause an increase in leaking of underground storage tank (UST) systems, which include not only the tank but also the piping and connecting hardware.
Oak Ridge National Laboratory
Funded from the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office.