Energy Content

With conventional diesel fuels, the inherent energy content of the fuel is the largest factor affecting the fuel economy, torque, and horsepower delivered by the fuel. The energy content of conventional diesel can vary up to 15% from supplier to supplier and from summer to winter. This variability is due to changes in its composition that are determined by the petroleum feedstock, as well as refining and blending practices to produce finished diesel fuels. No. 2 diesel fuel usually has higher energy content than No. 1 diesel fuel, with blend values somewhere in between.

With B100, the refining (esterification or transesterification) process and blending of B100 from different feedstocks has no significant effect on energy content. The energy content of B100 varies little because the energy content of the fats and oils used in biodiesel production is highly similar. Therefore, B100 made from most of the common feedstocks will have the same fuel economy, power, and torque when burned in an engine. Compared to most No. 2 diesel fuel in the United States, B100 has a slightly lower energy content (12.5% per pound or 8% per gallon). Typical No. 2 diesel fuel has an energy content of around 18,200 Btu/lb. Losses in power, torque, and fuel economy would be expected to be proportional to the difference in energy content, although any differences may be too small to notice. The energy content of biodiesel blends and diesel fuel is proportional to the amount of biodiesel in the blend and the heating value of the biodiesel and diesel fuel used to make the blend. For example, B20 users experience a nearly 1% loss in fuel economy on average, which may not be noticeable to the driver, and rarely report changes in torque or power.