Biodiesel is made from renewable resources such as vegetable oils, animal fats or cast-off greases. It is a renewable diesel operating like the traditional diesel. Biodiesel can be used in its untainted structure as a fuel for vehicles, but usually it is used as a diesel stabilizer in diesel-powered vehicles, which helps to diminish the levels of carbon monoxide, particulates and hydrocarbons. Biodiesel can be used single-handedly or can be combined with petrodiesel. In United States it’s regulated as mono-alkyl ester.