Alternative fuel refers to methods of powering an engine that do not involve petroleum (oil). Some alternative fuels are hydrogen, natural gas, hithane, and electricity.

Some of these come into the category of renewable energy. Renewable energy includes electricity generation for the home, while the term "alternative fuels" tends to refer to mobile energy. Some alternative fuels and the cars they power are : ethanol, oil shale, steam engine cars (like the Stanley Steamer), coal-oven steam cars, electric vehicle, electric cars recharged by solar cells, Tesla's electric car (with antenna), hydrogen fuel cell (see hydrogen car), hydrogen internal-combustion car (see hydrogen car), Water Fuel Cell, hempseed oil fuel, organic fuel (garbage), gas vaporizing carburetor, magnet car, and air car. Some less conventional alternative fueled cars are : wind-up car, nuclear powered, rubber band (stored energy), spring power (stored energy), and wind-powered sail cars. Most alternative fuels are designed to be cheap, non-polluting, non-finite sources of fuel or power.