In the simplest form, an alternative fuel is one that is not produced by using crude oil. They are
simply fuels that replace conventional gasoline as a means of powering vehicles. Alternative
fuels have desirable energy efficiency and pollution reduction features. The 1990 Clean Air Act
encourages development and sale of alternative fuels.
More specifically, the Energy Policy Act (EP Act) of 1993 gave a more in-depth definition of
what they consider to be alternative fuels. The United States Department of Energy recognizes
the following as alternative fuels: