Over the past decades, fossil fuel have been polluting the emviroment. But ,recentry some fuels is paid attention. Biofuels can be made from renewable natural resources, whareas fossil fuels are non-renewable resources. Corn ethnol fuel and fuel made from switch grass are two of the most promising altanative fuels or biofuels. Biofuel is used so as to automotive engin. And, just like regular gasoline powered cars, biofuels emit carbon dioxide, but up to 94 percent less. Corn ethanol habe adovantage that it burns hotter than gasoline. This is good for engin efficiency. However, there are disadvantage. It is relate to the energy needed to grow the corn, transport it to the refinery plant and process it into ethanol. The entive process is very intensive and wasteful. Moreover, growing corn for the ethanol market uses up valuable agricultural land. And corn has caused prices to rise. Switch grass is a perennial crop, meaning that it grows all year long. Through afrefining process, switch grass is turned into cellulosic ethanol which can be used in car engines. Fortunatery, switch grass is the one biofuel that does not adversery affect food prices.