Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.
Experimental French Régiolis Class train using biodiesel
Biodiesel sample
Rudolf Diesel
Older diesel Mercedes are popular for running on biodiesel.
Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricultural, domestic or industrial biowaste. Biofuels are mostly used for transportation, but can also be used for heating and electricity. Biofuels are regarded as a renewable energy source. The use of biofuel has been subject to criticism regarding the "food vs fuel" debate, varied assessments of their sustainability, and possible deforestation and biodiversity loss as a result of biofuel production.
A sample of biodiesel
Biofuel pumps, 2010
A biofuel truck in 2009
Neat ethanol on the left (A), gasoline on the right (G) at a filling station in Brazil in 2008