Biodiesel is a form of diesel fuel derived from plant & animal products. Biodiesel, as opposed to used vegetable oil sometimes used to fuel converted diesel engines, is a “drop-in biofuel,” compatible with existing diesel engines and distribution infrastructure.

Feedstock & Technologies

Biodiesel is produced by the reaction of a vegetable oil or animal fat with an alcohol (typically methanol) in the presence of a catalyst to yield mono-alkyl esters (biodiesel or methyl ester) and glycerin (~10% by weight). This reaction is called transesterification.

Raw or refined vegetable oil or recycled greases that have not been processed into biodiesel are not biodiesel.

Applications

Biodiesel has a higher cetane number than diesel fuel, allowing low-level blends to provide similar fuel consumption, horsepower, and torque as fossil diesel fuel. Biodiesel provides significant lubricity improvement over petroleum diesel fuel, which can lengthen engine life.

Biodiesel blends are designated BXX, where XX represents the volume percentage of biodiesel fuel in the blend. The most common blends are B5 and B20; pure biodiesel is referred to as B100.

Biodiesel can be used in unmodified diesel engines and with little or no change to fueling infrastructure for blends up to 20% (B20). Hundreds of millions of on-road kilometers and countless marine and off-road applications, as well as extensive studies, have demonstrated biodiesel’s power and efficiency across the full range of duty cycles, climatic conditions, and applications.

B20 has been widely available in high-blend states such as Minnesota, Illinois and Iowa, and also at truck stops across the US. B20 blends are not generally recommended for model year 1993 and older engines. (Certain elastomers soften and degrade with prolonged exposure to higher levels of biodiesel; B100-compatible materials have been used since 1994.)