Ive heard biodiesel called B20 and B100, what does that mean?
The designation B followed by a number indicates the amount of biodiesel used in a biodiesel/petroleum diesel blend. So B20 would be 20% biodiesel/80% petrodiesel. B100 is the term used for 100% biodiesel. B5 and B20 blends are commonly used as they greatly reduce the emissions relative to pure petroleum diesel, and also may be useful in very cold climates. So technically only B100 should actually be called biodiesel, but many people in the industry use the term to describe a diesel blend with any amount of biodiesel in it.