Ethanol is a naturally oxygenated fuel produced by fermenting organic materials such as corn, grains, crop waste materials, and forestry waste materials. Ethanol is usually blended with gasoline at different levels. E10 is a premium high-octane gasoline for cars and E85 (85% ethanol 15% gasoline) is used as an alternative fuel for light-duty vehicles.
E10 can be used in any gasoline vehicle without modification. E85, however, offers a higher octane rating and must be used in specified vehicles. All major domestic automakers offer E85 compatible vehicles, or flexfuel vehicles (FFVs), at prices comparable to gasoline vehicles. According to the National Ethanol Vehicle Association, there were approximately six million E85 vehicles on U.S. roads by the end of model year 2006. Applications for E85 include non-diesel fleet vehicles, buses, light-duty vehicles and delivery trucks.