Biofuel
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Biofuel is any fuel that derives from biomass - recently living organisms or their metabolic byproducts, such as manure from cows. It is a renewable energy, unlike natural resources such as petroleum, coal and nuclear fuels.
Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work.
The carbon in biofuels recently was extracted from atmospheric carbon dioxide by growing plants, so burning it does not increase the average amount of carbon dioxide.
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Classes of Biofuels
Solid
There are many forms of solid biomass that are combustible as a fuel such as:
Liquid
There are also a number of liquid forms of biomass that can be used as a fuel:
- Bioalcohols — see alcohol as a fuel.
- Ethanol produced from sugar cane is being used as automotive fuel in Brazil. Ethanol produced from corn is being used as a gasoline additive (oxygenator) in the United States.
- Methanol, which is currently produced from natural gas, can also be produced from biomass — although this is not economically viable at present.
- Biologically produced oils can be used in diesel engines:
- Straight vegetable oil (SVO).
- Waste vegetable oil (WVO).
- Biodiesel obtained from transesterification of animal fats and vegetable oil.
- Oils and gases can be produced from various wastes:
- Thermal depolymerization can extract methane and oil similar to petroleum from waste.
- Methane and oils are being extracted from landfill wells and leachate in test sites.
Gaseous
- Methane produced by the nature decay of garbage or agricultural manure can be collected for use as fuel.
- Hydrogen can be produced by cracking any hydrocarbon fuel in a reformer or by the electrolysis of water.
- Gasification
See also
External links
fr:Biocarburant
