Future Fuel (Bio Diesel)

TECH Cleaner-burning than ethanol, with vastly better fuel economy, biodiesel could soon move beyond the fryer-grease fringe it's often associated with. Made largely from soybean oil or recycled cooking oil, biodiesel runs fine in unmodified diesel engines at up to a 20 percent blend with 80 percent petroleum diesel, a combination known as B20. Mercedes is conservative with its warrantied vehicles, recently announcing that drivers of Bluetec and CDI diesels could run B5; the same is true for Jeep's Liberty and the upcoming Grand Cherokee diesel. (In Europe, Citroën and Peugeot diesels can run up to B30.) Pure liquid biodiesel thickens at low temperatures, however, creating challenges for cold-climate storage and operation.

GREEN BENEFITS Biodiesel's greenhouse-gas emissions are about one third lower than gasoline. A University of Minnesota study found that biodiesel creates 93 percent more energy than is used to produce it, compared with just 25 percent for ethanol.

ECONOMICS B20 fuel contains only 2 percent less energy than regular diesel, so it delivers terrific mileage: 20 to 40 percent better than gasoline. Prices vary by region because of the limited supply sources, and it costs more than either gasoline or petroleum diesel.

OUTLOOK Despite efforts toward large-scale biodiesel production, for now it's a mere drop in a huge national reservoir of gasoline. Just 225 million gallons were produced in the U.S. last year, about as much gasoline as the nation guzzles in a day. There are only about 1,000 pumps nationwide, and any growth in that number depends on a rise in diesel usage. Biodiesel has better prospects in Europe, where diesel holds half the car market and the European Union produces nearly 90 percent of the world's biodiesel.

EST. MARKET SHARE IN 2027: 4% (B20)