Biodiesel burns clean, which results in a significant reduction of the types of pollutants that contribute to smog and global warming and emits up to 85% fewer cancer-causing agents. It is the only alternate fuel approved by the Environmental Protection Agency (EPA), has passed every Heath-Effects Test of the Clean Air Act and meets the requirements of the California Air Resources Board (CARB).
Biodiesel is made using an alcohol like methanol and a chemical process that separates glycerine and methyl esters (biodiesel) from fats or vegetable oils. Glycerine is used in many common products including soap and is highly marketable; therefore there is little waste in the process. That said, growing crops requires time and significant investment, and the fuel must be made and shipped to a local station. For these reasons biodiesel is more expensive than petroleum, gallon for gallon. This must be considered against the many economic advantages, however, that arise from a domestic form of fuel, a cleaner environment, an improvement in air quality, and a reduction of cancer-causing agents.
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.