What is biodiesel made from?
Usually derived from vegetable oils -- soy is very popular these days, but animal fats can also be used -- biodiesel is made through a chemical process called transesterification which essentially splits the oil into two parts: alkyl esters and glycerine; the esters are the fuel, while the leftover glycerine is often used to make soap and other beauty products. Both virgin and waste oil (often collected from restaurants) can be used in this process with equally good results. The fuel can be produced domestically, from seed to pump, and is non-toxic and biodegradable. It typically produces about 60% less net carbon dioxide emissions than petroleum-based diesel, as it is itself (partially, at least) produced from atmospheric carbon dioxide via photosynthesis in plants.
Biodiesel in diesel engines: no conversion needed!
A common misconception is that engine modification is needed to use biodiesel. This is simply not true: any diesel engine can burn biodiesel without any modification; it?s a straight fill-up-and-go affair. This differs from both waste vegetable oil (WVO) and straight vegetable oil (SVO -- both coming later in this series), which is what biodiesel often starts its life as. Many biodiesel drivers do report a pleasant, French-fry-like smell coming from the tailpipe, though.