Biofuels are liquid and gaseous fuels which are in some way derived from biomass. Biofuels are gaining increased public and scientific attention, driven by factors such as oil price spikes and the need for increased energy security.
Bioethanol is an alcohol made by fermenting the sugar components of plant materials and it is made mostly from sugar and starch crops. With advanced technology being developed, cellulosic biomass, such as trees and grasses, are also used as feedstocks for bioethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase gasoline's octane number and improve vehicle emissions. Bioethanol is widely used in the United States and in Brazil.
Biodiesel is made from vegetable oils, animal fats or recycled greases. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel oil additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is the most common biofuel in Europe.
Biofuels provided 1.8% of the world's transport fuel in 2008. Investment into biofuels production capacity exceeded $4 billion worldwide in 2007 and is growing.
- Towards Sustainable Production and Use of Resources: Assessing Biofuels. United Nations Environment Programme (October 16, 2009). Retrieved on October 24, 2009.