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Fuels and Fuel Additives

Renewable and Alternative Fuels

Gasoline and diesel have long been the predominant vehicle fuels in the United States, but today, concerns ranging from greenhouse gas emissions to energy security are spawning new interest in other sources of energy for cars, trucks, and motorized equipment. Fuels such as natural gas, propane, alcohol, and electricity can also power the nation's motor vehicle fleet. These fuels are attractive because of their potential to offer a clean-burning, domestically-produced alternative to imported petroleum.

The terms "alternative fuels" and "renewable fuels" are sometimes used interchangeably, although they carry very specific meanings in statute and regulation. The definitions even differ from law to law. In general, however, alternative fuels are understood to mean alternatives to traditional gasoline and diesel fuels. Renewable fuels are those derived from renewable, non-petroleum sources such as crops, animal waste, or municipal solid waste.

Renewable Fuels (Renewable Fuel Standard Program)

Renewable fuels include liquid and gaseous fuels and electricity derived from renewable biomass energy sources, as opposed to fossil fuels. Many renewable fuels achieve significant lifecycle greenhouse gas emissions reductions relative to fossil fuels. Increased use of renewable fuels in the United States can reduce dependence on foreign sources of crude oil and foster development of domestic energy sources, while at the same time providing important reductions in greenhouse gas emissions that contribute to climate change.

To accelerate use of fuels derived from renewable sources, Congress established standards under the Energy Policy Act of 2005 designed to encourage the blending of renewable fuels into our nation's motor vehicle fuel supply. Congress strengthened the renewable fuels program under the Energy Independence and Security Act of 2007 to include specific annual volume standards for total renewable fuel and also for the specific renewable fuel categories of cellulosic biofuel, biomass-based diesel, and advanced biofuel. The revised statutory requirements also include new criteria for both renewable fuels and for the feedstocks used to produce them, including lifecycle greenhouse gas emission thresholds.

Other Information

Alternative Fuels

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 original manufacturer. Others are converted to run on an alternative fuel by modifying the engine controls and fueling system from the original configuration.

Alternative Fuel Topics

External Links

If you have questions or request information, please contact the appropriate support or help line found on the Support & Help page.

Please visit EPA's Transportation and Air Quality web-based repository of mobile source documents, Document Index System (DIS). This searchable repository contains regulations, Federal Register notices, policy letters, and guidance documents.

Please visit our Related Links page for other fuel related information within EPA, other U.S. Agencies, and other fuel related websites.

This page is maintained by EPA's Office of Transportation and Air Quality (OTAQ).
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