The growing interest in alternative fuels for cars and trucks is motivated by three important considerations:
- Alternative fuels generally produce fewer vehicle emissions like nitrogen oxides and greenhouse gases;
- Most alternative fuels are not derived from finite fossil-fuel resources; and
- Alternative fuels can help any nation become more energy independent.
The U.S. Energy Policy Act of 1992 identified eight alternative fuels. Some are already widely used; others are more experimental or not yet readily available. All have potential as full or partial alternatives to gasoline and diesel.01of 08
Ethanol as an Alternative Fuel
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Ethanol is an alcohol-based alternative fuel that is made by fermenting and distilling crops such as corn, barley or wheat. Ethanol can be blended with gasoline to increase octane levels and improve emissions quality.
Natural Gas as an Alternative FuelCompressed natural gas (CNG) fuel door.
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Natural gas, usually as Compressed Natural Gas, is an alternative fuel that burns clean and is already widely available to people in many countries through utilities that provide natural gas to homes and businesses. When used in natural gas vehicles-cars and trucks with specially designed engines-natural gas produces far fewer harmful emissions than gasoline or diesel.03of 08
Electricity as an Alternative Fuel
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Electricity can be used as a transportation alternative fuel for battery-powered electric and fuel-cell vehicles. Battery powered electric vehicles store power in batteries that are recharged by plugging the vehicle into a standard electrical source. Fuel-cell vehicles run on electricity that is produced through an electrochemical reaction that occurs when hydrogen and oxygen are combined. Fuel cells produce electricity without combustion or pollution.
Hydrogen as an Alternative Fuel
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Hydrogen can be mixed with natural gas to create an alternative fuel for vehicles that use certain types of internal combustion engines. Hydrogen is also used in fuel-cell vehicles that run on electricity produced by the petrochemical reaction that occurs when hydrogen and oxygen are combined in the fuel “stack.”05of 08
Propane as an Alternative Fuel
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Propane-also called liquefied petroleum gas or LPG-is a byproduct of natural gas processing and crude oil refining. Already widely used as a fuel for cooking and heating, propane is also a popular alternative fuel for vehicles. Propane produces fewer emissions than gasoline, and there is also a highly developed infrastructure for propane transport, storage and distribution.06of 08
Biodiesel as an Alternative Fuel
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Biodiesel is an alternative fuel based on vegetable oils or animal fats, even those recycled after restaurants have used them for cooking. Vehicle engines can be converted to burn biodiesel in its pure form, and biodiesel can also be blended with petroleum diesel and used in unmodified engines. Biodiesel is safe, biodegradable, reduces air pollutants associated with vehicle emissions, such as particulate matter, carbon monoxide and hydrocarbons.07of 08
Methanol as an Alternative FuelMethanol molecules.
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Methanol, also known as wood alcohol, can be used as an alternative fuel in flexible fuel vehicles that are designed to run on M85, a blend of 85 percent methanol and 15 percent gasoline, but automakers are no longer manufacturing methanol-powered vehicles. Methanol could become an important alternative fuel in the future, however, as a source of the hydrogen needed to power fuel-cell vehicles.08of 08
P-Series Fuels as Alternative Fuels
P-Series fuels are a blend of ethanol, natural gas liquids and methyltetrahydrofuran (MeTHF), a co-solvent derived from biomass. P-Series fuels are clear, high-octane alternative fuels that can be used in flexible fuel vehicles. P-Series fuels can be used alone or mixed with gasoline in any ratio by simply adding it to the tank.