By now, most freshmen students of alternative fuels know that ethanol is primarily made from corn, sorghum or sugarcane and that biodiesel comes from vegetable oils.

But did you know that a less expensive source of biodiesel comes out of animal rendering plants?

That’s right. The old gray mare is already providing horsepower (we couldn’t resist) for diesel-powered trucks and sedans, and other animals are giving their parts, too, to help American reduce its dependency on imported petroleum.

Writing in the July issue of Biodiesel Magazine, Nicholas Zeman informs us that “material from rendering plants is considered a choice feedstock for the production of renewable diesel.”

Apparently, there’s lots of it around. Zeman says that “With 273 facilities in the United States, the rendering industry processes 60 billion pounds of raw materials a year and generates billions of dollars in revenue.”

His article, “Recycling for Renewables” is an interesting piece. We recomend, however, that you don’t read it over lunch, especially if you packed a nice Spam sandwich.