Biodiesel (or bio-diesel) is a diesel that is produced from vegetable oils rather than petroleum oil. To create the biodiesel, it must be processed using methanol. The biodiesel can then be used in virtually any diesel engine without any modifications.
Common sources of vegetable oil include canola, corn and waste vegetable oil.
Biodiesel is usually sold as a blend with regular diesel. For example B5 is 5% biodiesel, 95% conventional diesel.