DesMoinesRegister.com

DesMoinesRegister.com: "The idea that vegetable oil could be used as an engine fuel has been around for more than a century. But it wasn't until the 1990s that commercial production of biodiesel began in the United States. Production has skyrocketed from under 1 million gallons in 1999 to 91 million gallons last year.

Biodiesel can be produced from palm, canola, cottonseed and other vegetable oils or from animal fats, including beef, pork or poultry. Research has even explored using algae. But the primary feedstock in America has been soybean oil. Iowa led the nation in soybean production four of the past five years, topping Illinois in all but 2003. Likewise, Iowa leads the nation in biodiesel production capacity, edging Texas, according to a September compilation from the National Biodiesel Board.

Diesel engines have long been attractive as a more powerful, fuel-efficient alternative to similar-sized gasoline engines - delivering 30 percent to 35 percent greater fuel efficiency. But the soot and smell were turnoffs for most American drivers. Today's diesel fuel has cleaned up its act. Petroleum-based diesel meets the same emissions standards as gasoline. And biodiesel, while slightly less fuel efficient than petrodiesel, reduces emissions of several greenhouse gases."