What is Biodiesel?

Biodiesel is a form of diesel fuel that is natural and renewable and is manufactured from vegetable oils, mostly soy and corn, and animal fats. It primarily comes from soy and corn, contains no petroleum, is nontoxic, and biodegradable. In addition, biodiesel produces less air pollutants and carcinogens than petroleum-based diesel.

Is Biodiesel Safe For My Vehicle?
Biodiesel can be used in its pure form (B100) or blended with petroleum diesel. Common blends include B2 (2% biodiesel), B5, and B20. B2 and B5 can be used safely in most diesel engines. However, most vehicle manufacturers do not recommend using blends greater than 5%—using higher blends will void some engine warranties. Check with your owner’s manual or vehicle manufacturer to determine the right blend for your vehicle.

Biodiesel has been rigorously and independently tested in virtually every type of diesel engine by a number of agencies in the laboratory and on the road. The National Biodiesel Board (NBB) reports the tests combine to account for over 50-million street miles plus intense off-road and marine use. Performance is said to rate comparably to petroleum in all areas from power to efficiency, hauling and climbing. It can be used in its pure form or blended with petroleum fuel. The most common mix is 20/80, referred to as "B20" containing 20% biodiesel by volume, and 80% petroleum.

Biodiesel can be used in any diesel engine with few to no modifications. The main effect is super-lubrication which has the benefit of acting like a solvent to clean the engine. If the engine has been previously running on conventional diesel this can result in an initial need to change fuel filters until sludge left by petroleum fuel is purged. This effect is more pronounced when using B100 (100% biodiesel), and may be less so with B20. Precautionary measures should be taken however, by checking the fuel filter after initial hours of running blended or neat fuel (100% biodiesel).

When using B100 exclusively, the lubrication could degrade certain types of rubber over time, which may require replacement of fuel hoses or fuel pump seals. This isn't as much of a concern with newer engines that contain parts designed for low-sulphur diesel (known as #2 diesel), as these parts are also compatible with biodiesel. The use of B20 did not result in the need to replace hoses or seals in the many miles of tests previously mentioned.

Like conventional diesel, biodiesel will cloud and gel at very cold temperatures, but blends like B20 are only slightly more sensitive than #2 diesel in this respect. The recommendations are the same regardless of blend: park the vehicle in or near shelter if possible; use optional fuel heaters; or mix with #1 diesel.

Biodiesel should not impact or void the manufacturer's warranty of any compression-ignition motor (diesel), however, it's always safest to check your warranty first. Call the manufacturer if unsure.

What Are The Environmental Benefits Of Biodiesel?

In 2000, biodiesel became the only alternative fuel in the country to have successfully completed the EPA-required Tier I and Tier II health effects testing under the Clean Air Act. These independent tests conclusively demonstrated biodiesel’s significant reduction of virtually all regulated emissions, and showed biodiesel does not pose a threat to human health. Biodiesel contains no sulfur or aromatics, and use of biodiesel in a conventional diesel engine results in substantial reduction of unburned hydrocarbons, carbon monoxide and particulate matter. A U.S. Department of Energy study showed that the production and use of biodiesel, compared to petroleum diesel, resulted in a 78.5% reduction in carbon dioxide emissions. Moreover, biodiesel has a positive energy balance. For every unit of energy needed to produce a gallon of biodiesel, 3.24 units of energy are gained. Additionally, biodiesel is made using an alcohol such as methanol, along with soy, corn, or animal fats, in a chemical process that separates glycerine and biodiesel. The residual glycerine can then be used in many common products such as soap, which results in very little waste in the manufacturing process.

What are the Economic Benfits of Biodiesel?
The use of biodiesel benefits the U.S. economy by reducing dependence on foreign oil while increasing the use of naturally occurring products in the U.S. In recent years, the prices of agricultural commodities such as corn and soy have hit record lows, while the price of oil is at a record high. Biodiesel allows U.S. companies to utilize domestic surpluses of vegetable oils by manufacturing them using existing industrial production capacity and conventional equipment.

wheat field picture

Quick Facts

Biodiesel Compared to Petroleum Diesel Advantages

  • Domestically produced from non-petroleum, renewable resources

  • Can be used in most diesel engines, especially newer ones

  • Less air pollutants (other than nitrogen oxides) and greenhouse gases

  • Biodegradable

  • Non-toxic

  • Safer to handle

  • Use of blends above B5 not yet warrantied by auto makers

  • Lower fuel economy and power (10% lower for B100, 2% for B20)

  • Currently more expensive

  • More nitrogen oxide emissions

  • B100 generally not suitable for use in low temperatures

  • Concerns about B100's impact on engine durability

National Biodiesel Board, www.biodiesel.org