A 2-million-mi. over-the-road field test of biodiesel-blended fuel has passed the 1.6-million-mi. mark and should be wrapped up by November of this year, with detailed data analysis on fuel performance available by spring 2009.

“What this test is designed to do is provide a roadmap for the successful use of B20,” said Dr. Don Heck, coordinator of the biotechnology and biofuels program at Iowa Central Community College, as well as the director of the 2-million-mi. haul field test.

B20 is a blended fuel made up of 20% biodiesel — in this case made largely from soybean oil — with 80% regular No. 2 diesel fuel. Refrigerated and flatbed carrier Decker Truck Lines of Ft. Dodge, IA, is participating in the study, using 20 trucks in its 600-truck fleet — 10 operating on diesel and 10 using B20 biodiesel.

To date, Heck noted that the fuel economy difference between B20 and regular diesel is around 2% for the entire study, narrowing to 1% in the summer months. On average, Decker's Peterbilt 378s and 386s equipped with 475 hp. Caterpillar engines are achieving 6.25 mpg with diesel and 6.12 mpg with B20.

Heck noted that other B20 metrics are being confirmed by the study as well. So far, petroleum diesel has a higher energy content, with 2.7% more Btu than B20; but B20, in turn, has a 1.8-point higher cetane rating. Oil analysis shows that B20 produces more soot in the oil, while there's been a higher level of some metals in the oil from using regular diesel.