Ethanol

Ethanol is another popular alternative fuel that is usually made from fibrous materials like wood chips or from the starch or sugar found in common crops like corn. Ethanol burns cleaner than gasoline while reducing greenhouse gases.

Ethanol is already in use, powering nearly six million flex-fuel vehicles already on the road. The United States is widely considered the world's largest ethanol producer, cranking out 4.6 billion gallons of ethanol each year.