Over the past several decades, fossil fuels have been polluting the environment. Biofuels can be made from renewable natural resources whereas fossil fuels are non-renewable resource. Corn ethanol fuel and fuel made from switch grass are two of the most promising alternative fuels or biofuels.
By definition, biofuels are fuels that are comprised of biological ingredients like plant material. In order to be used in an automotive engine, plant material has to go though a refining process. This process turns raw plant material into ethanol.
Methanol and Ethanol fuel are typically a primary sources of energy; they are convenient fuels for storing and transporting energy. These alcohols can be used in "internal combustion engines as alternative fuels", with butanol also having known advantages, such as being the only alcohol-based motor fuel that can be transported readily by existing petroleum-product pipeline networks, instead of only by tanker trucks and railroad cars.
The U.S. government has encouraged farmers to sell their corn to biofuel refineries, which has caused prices to rise substantially much more than any other biofuel source and more than selling corn for animal feed.