Biodiesel is a liquid fuel used to power compression-ignition engines manufactured from vegetable oils, animal fats and recycled restaurant grease. It can be used in any equipment that operates on diesel fuel.

Using biodiesel reduces lifecycle emissions because carbon dioxide released from biodiesel combustion is offset by the carbon dioxide absorbed from growing soybeans or other feedstocks used to produce the fuel. It is less combustible than petroleum fuel.

It can crystallize in very cold weather, so users must be cautious about the blend used. It is produced in the United States, often with soybeans, which yields 4.56 units of energy for every unit of fossil energy consumed over its life cycle, according to a study by the United States Department of Agriculture.

Renewable diesel, which is not the same as biodiesel, is a hydrocarbon. Renewable diesel fuel is made from fats and oils, such as soybean oil or canola oil. It is processed to be chemically the same as petroleum diesel. Renewable biodiesel can fully replace petroleum diesel or can be blended with petroleum diesel. Nearly all domestically produced and imported renewable diesel is used in California due to economic benefits under the Low Carbon Fuel Standard in that state.