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 through a refining process. This process turns raw plant material into ethanol Both corn ethanol and switch grass fuels come from plants that are replenishable. That means they can be grown over and over again. Just like regular gasoline- powered cars, biofuels emit carbon dioxide, but up to 94 percent less. Corn Ethanol One advantage of corn ethanol is that it burns hotter than gasoline. Although this is good for engine efficiency, corn ethanol has lower energy content. This means that it takes more corn ethanol fuel to produce the same amount of power compared to engines using gasoline Other disadvantages relate to the energy needed to grow the corn, transport it to the refinery plant and process it into ethanol. The entire process is very energy-intensive and wasteful. Moreover, growing corn for the ethanol market uses up valuable agricultural land. Despite these com ethanol fuel has become very popular. The Us. encouraged farmers to sell their government has corn to biofuel refineries. which has caused prices substantially-much more than any other biofuel than corn for animal feed source and more selling