• Biodiesel is a fuel derived from oils and fats that provides domestic, renewable, cleaner fuel for compression-ignited engines. Biodiesel is produced here in the US and can be blended into traditional diesel fuel in any proportion, but some of the more popular blends include B2, B5, B20, and B99/100. The more biodiesel that is blended into the fuel, the better the emissions properties of the vehicle will be, but there are advantages to each blend depending on how a vehicle operates.