17-05-2016, 10:43 AM
Ethanol is a renewable fuel made from corn and other plant materials. The use of ethanol is widespread, and approximately 97% of gasoline in the U.S. contains some ethanol. The most common blend of ethanol is E10 (10% ethanol, 90% gasoline). Ethanol is also available as E85 (or flex fuel)—a high-level ethanol blend containing 51%-83% ethanol depending on season and geography—for use in flexible fuel vehicles. E15 is defined by the Environmental Protection Agency as a blend of 10.5%-15% ethanol with gasoline. It is an approved ethanol blend for use in model year 2001 and newer light-duty conventional vehicles.
Energy Security
Depending heavily on foreign petroleum supplies puts the United States at risk for trade deficits and supply disruption. In 2014, 27% of petroleum products were imported. That number has declined during the past 10 years because of increased domestic crude supplies and ethanol production.
Fuel Economy and Performance
A gallon of ethanol contains less energy than a gallon of gasoline. The result is lower fuel economy than a gallon of gasoline. The amount of energy difference varies depending on the blend. For example, E85, with 83% ethanol content, has about 27% less energy per gallon than gasoline (the impact to fuel economy lessens as ethanol content decreases). Gasoline vehicles, including flexible-fuel vehicles (FFVs), are optimized for gasoline. If they were optimized to run on higher ethanol blends, the fuel economy penalty would likely be less.