Alternative fuels include gaseous fuels such as hydrogen, natural gas, and propane; alcohols such as ethanol, methanol, and butanol; vegetable and waste-derived oils; and electricity. These fuels may be used in a dedicated system that burns a single fuel, or in a mixed system with other fuels including traditional gasoline or diesel, such as in hybrid-electric or flexible fuel vehicles.
Some vehicles and engines are designed for alternative fuels by the manufacturer. Others are converted to run on an alternative fuel by modifying the engine controls and fueling system from the original configuration.
Biodiesel Fuel Fact Sheets
Learn more about alternative fuels on the Department of Energy.