diesel99B99 Biodiesel is a hh-level biofuel blend consisting of up to 99.9 percent biodiesel and 0.1 percent petroleum diesel. B99 and other hh-level blends (B100) are less common than B20 and other low-level blends.What is renewable diesel fuel (R99)? Often called green diesel or second generation diesel, it refers to petrodiesel-like fuels derived from biological sources that are chemically not esters