This type of fuel is considered to be more friendly to the environment.. The main type of biofuel available in America is corn-based ethanol. This is added to gasoline as an anti-knock compound. It replaces previously used compounds like tetramethyl lead and MTBE.
Biofuels are produced from organic plant material rather than petroleum. This organic material can come from plants such as sugar cane, soybean and corn or from animal products like fat and waste.
One prominent biofuel is biodiesel. Plant oils and/or animal fats are combined with alcohol and catalyzed to form ethyl or methyl esters. They are sold either neat, as 100% biodiesel, or blended with conventional diesel oil. Other forms of biofuels are biologically produced alcohols and biogases. 
Increases in the price of fossil fuels, combined with fears of a shortage in the future, have spurred research into biofuels as a clean and renewable energy source. The US, European and other governments have put measures in place encouraging the production of biofuels.
However, the enthusiasm for biofuels has led to deforestation as natural forests in countries such as Indonesia, Malaysia and Thailand have been cleared to plant oil palms, considered to be one of the best and cheapest sources of biodiesel. Large areas of the Amazon have been burned to plant more sugar and soybeans. This has led to habitat destruction for animals, particularly the increasingly-rare orangutans, and the monoculture of plantations replacing the variety of species in native forests. Almost 50,000 acres of forest a day are lost. Because that number includes the planting of plantation forests, it masks the true loss of tropical forests, which is almost 100,000 acres a day, or more than twice the size of Washington, D. C. Deforestation is the largest cause of increasing greenhouse gases in the atmosphere. 
A recent 10-year evaluation of native grassland perennials by the University of Minnesota concluded that biofuels from this source could displace about 13% of global petroleum without losing agricultural land. Their study indicated that the process was carbon negative in that it removed more carbon dioxide from the atmosphere than was released by the combustion of fossil-fuel during the processes involved in agriculture, transportation and processing. Opponents of this kind of land use point out, however, that in the US the use of corn to produce ethanol encourages monoculture farming, which leaves soils eroded and water polluted. 
There is a concern that the production of biofuels will reduce the amount of food, and thus raise food prices. High food prices most affect poor people, who spend a larger percentage of their income on food. 
Biofuels from Waste
Bio-fuels may also be manufactured from products which would otherwise be considered waste. For example used cooking oil is collected by people who use it to manufacture bio-diesel for their own use. There are a variety of processes that may be used (called "recipes" among home bio-diesel makers). In undeveloped locations, animal waste is fed into anaerobic composters to produce methane gas for fuel, usually only on a small, household scale. Dried dung is also used in undeveloped areas as a replacement for firewood. While these applications provide benefits both by easing the load on mineral fuel sources and by re-processing and recycling end products that would otherwise present disposal difficulties, bio-fuels from waste have not been pursued on large scales. 
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