Alternative Fuels Definition

An alternative fuel is any non-conventional substance that is used to produce energy. In relation to vehicles, conventional fuels include gasoline and diesel. Virtually any type of energy used to power a car that is not derived completely from fossil fuels is considered an alternative fuel.

Biomass

The first category of alternative fuels is called biomass. Biomass fuels are derived from biological materials, most frequently grains such as corn or sugar cane. Some popular biomass fuels include biofuel, biodiesel and vegetable oil.

Alcohol Fuels

Another classification of alternative energy is alcohol fuels. These fuels use alcohols such as ethanol or methanol to power the vehicle's engine. Ethanol is commonly mixed with gasoline or diesel to make a blended fuel. The most common blended fuel is known as E85, which contains roughly 85 percent ethanol and 15 percent gasoline.

Electricity

Electricity is also considered an alternative fuel when used to power motor vehicles. These automobiles utilize specialized batteries as opposed to traditional engine fuel. Electric and hybrid electric vehicles are becoming more and more popular. Full electric vehicles must be recharged via an external power outlet. Hybrid vehicles have the ability to recharge their batteries without such an inconvenience.

Compressed Natural Gas

Compressed natural gas (CNG) is another fuel source that has already been put to use in commercial automobiles. Though derived from fossil fuels, it is considered an alternative fuel. The main benefit of CNG is that is burns much cleaner than traditional gasoline or diesel fuel.

Possible Future Fuels

Alternative fuels that have been suggested for vehicle energy, but have yet to become viable, include compressed air and hydrogen. As it stands now, hydrogen availability is too scarce and too expensive to manufacture to find common use in vehicles. Compressed air, while considerably cheaper than fossil fuels, has yet to be harnessed for adequate engine power.