Ethanol

As an alternative fuel, ethanol is generally blended with 15 percent gasoline to make E85, but in some vehicles straight ethanol (E100) can be used. In such cases, substances such as methanol are added to ethanol to denature it, or make it unfit for drinking. Denaturing also allows ethanol manufacturers to bypass alcoholic beverage taxes and regulation.

Making enough ethanol to meet a large part of our transportation fuel needs would take vast amounts of grain. About 2.6 billion bushels of corn were made into 6.5 billion gallons of ethanol fuel in the United States in 2007. This represented 4.7 percent of the approximately 138 billion gallons of gasoline consumed that year.