Biodiesel = petroleum diesel?

The July/August 2007 guest column "Biodiesel from the Bench" by Joffre M. Berry, MCIC, was clear, accurate, and, therefore, acceptable--except for the statement that "Biodiesel is a biological equivalent of petroleum diesel." That is stretching it a bit. One could state more accurately that biodiesel fuel, like petroleum diesel fuel (ASTM International Specification D 975), is a fuel suitable for compression-ignition (diesel) engines. To claim equivalency is to contradict the article itself. Storage stability of biodiesel fuel is an admitted problem. It is best used as a 20 percent blend (B20) with petroleum diesel fuel. So says the article. Continuing, it can have low temperature flow problems. And because oxygen is present in the molecules, biodiesel fuel is likely to possess less energy than pure hydrocarbons, the principle constituents of petroleum diesel fuel. Finally, there are all those years of experience backing the petroleum variety. Biodiesel fuel is the "babe in the woods" and will surely endure some growing pains. In light of the slow disappearance of sweet, light, easy-to-recover crude oil and the cheap products recovered therefrom, we do have to find alternatives. Biodiesel fuel is a logical one.

Paul L. Strigner, FCIC