Lower Energy Density

Neat biodiesel contains about 8% less energy per gallon than typical No. 2 diesel in the United States, or 12.5% less energy per pound. The difference between these two measurements is due to the higher density of biodiesel compared to diesel fuel. All biodiesel, regardless of its feedstock, provides about the same amount of energy per gallon or per pound. The energy content of petroleum diesel fuel typically varies more widely than that of biodiesel. However, some reference values are:

The difference in energy content between petroleum diesel fuel and biodiesel can be noticeable with B100. For B20, the differences in power, torque, and fuel economy are 1% to 2%, depending on the base petroleum diesel fuel. Most users report little difference in fuel economy between B20 and No. 2 diesel fuel. Any differences between B20 and No. 2 diesel fuel are about the same as would be expected between summer and winter diesel. As the biodiesel blend level is lowered, differences in energy content become proportionally less significant: blends of B5 or lower cause no noticeable differences in performance compared to No. 2 diesel.