Ethanol is a clean-burning, high-octane fuel that is produced from renewable sources. At its most basic, ethanol is grain alcohol, produced from crops such as corn. Because it is domestically produced, ethanol helps reduce America's dependence upon foreign sources of energy.
Pure, 100% ethanol is not generally used as a motor fuel; instead, a percentage of ethanol is combined with unleaded gasoline. This is beneficial because the ethanol:
decreases the fuel's cost
increases the fuel's octane rating
decreases gasoline's harmful emissions
Any amount of ethanol can be combined with gasoline, but the most common blends are:
E10 - 10% ethanol and 90% unleaded gasoline
E10 is approved for use in any make or model of vehicle sold in the U.S. Many automakers recommend its use because of its high performance, clean-burning characteristics. In 2004, about one-third of America's gasoline was blended with ethanol, most in this 10% variety.
E85 is an alternative fuel for use in flexible fuel vehicles (FFVs). There are currently more than 4 million to 6 million FFVs on America's roads today, and automakers are rolling out more than 1.5 million vehicles this year.. In conjunction with more flexible fuel vehicles, more E85 pumps are being installed across the country. When E85 is not avaialble, these FFVs can operate on straight gasoline or any ethanol blend up to 85%.
It is important to note that it does not take a special vehicle to run on "ethanol". All vehicles can use E10 with no modifications to the engine. E85 is for use in a flexible fuel vehicle, so some people confuse "ethanol" with the blend of 85% ethanol and 15% gasoline.
The following is a reference taken from the signing of the Energy Policy Act by President George W. Bush:
"The bill also will lead to a greater diversity of fuels for cars and trucks. The bill includes tax incentives for producers of ethanol and biodiesel. The bill includes a flexible, cost-effective renewable fuel standard that will double the amount of ethanol and biodiesel in our fuel supply over the next seven years. Using ethanol and biodiesel will leave our air cleaner. And every time we use a home-grown fuel, particularly these, we're going to be helping our farmers, and at the same time, be less dependent on foreign sources of energy."