Biodiesel refers to a vegetable oil or animal fat-based diesel fuel consisting of long chain alkyl (methyl, ethyl or propyl) esters. Biodiesel is typically made by chemically changing reacting lipids (e.g. vegetable oil, soybean oil, animal fat (tallow) with an alcohol producing fatty acid esters. Biodiesel is meant to be used in standard diesel engines. Biodiesel can be used with petro diesel in the proportions under 30%, like B5,B7,B10,B20,B30. Biodiesel blends can also be used as heating oil.