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Clean Fuels Program


Biodiesel is a clean-burning, renewable, non-toxic, biodegradable and environmentally-friendly transportation fuel that can be used in neat form or in blends with petroleum--derived diesel. As generally defined, "biodiesel" refers to alkyl or esters made by transesterifying vegetable oils and animal fats as well as used vegetable oils, fats and waste products for use in compression-ignition diesel engines.

The wide variety of potential feedstocks including soybean oil, rendered animal fats and used vegetable oils - yellow grease - means that some type of biodiesel could be produced in every region of the country. The renewable fuel standard and stricter U.S. Environmental Protection Agency emissions requirements for heavy-duty engines, both on- and off-road, including urban buses, have generated substantial interest in biodiesel. Its performance similarities to con-ventional "petrodiesel" have moved biodiesel into consider-ation as a clean-burning alternative fuel or fuel component that will be required in fleets and other applications well into the next century.

The principal bus engine manufacturers, Detroit Diesel Corporation, Cummins and Navistar, are cooperating with the Board in testing their engines. In blends of biodiesel of up to 30 percent by volume, no instances of fuel system degradation have been identified. In cooperation with the U.S. Bureau of Mines, the Board is also investigating engines operated in underground mines, as well as inside buildings such as warehouses.

Liquefied natural gas or propane, compressed natural gas, methanol and ethanol fuels have been under consider-ation and tested for over a decade. Biodiesel, a relative late-comer as an alternative fuel, is being tested extensively.

For more information on clean fuels programs browse our Publications and Current Events sections.