The so-called Two Million Mile Haul, sponsored by the National Biodiesel Board, Caterpillar and several government agencies, compares performance of 10 road tractors burning straight petroleum diesel with ten using B20 (diesel blended at 20 percent with biodiesel). Results have been monitored by Dr. Don Heck, a professor at Iowa Central Community College in Fort Dodge. The test began in August of 2006, and two years later, the 20 trucks had covered 1.6 million miles. Overall performance was much the same for both truck groups, Heck said.Fuel filter plugging showed up in therevenue runs thatcomprised the tests,especially those into Minnesota in winter.
While B20 delivered slightly worse fuel economy, it usually costs less than straight diesel, says Steve Lursen, special projects manager for Decker Truck Lines, the Fort Dodge-based fleet involved in the test. Prices for B20 ranged from 11 cents per gallon less to “slightly higher,” he says. Decker purchases B20 in bulk and has it delivered to its terminals, and that's where most of the trucks' tanks have been topped off. Some purchases are made by drivers when they find B20 available on the road.
Drivers affected tank mileage numbers by up to 23 percent, far more than petrol versus B20, Lursen said. To compensate, about halfway through the test he switched drivers between the two truck groups so the fuel economy numbers should statistically even out. Previous surveys of fleet operations by maintenance organizations and manufacturers have found that variances in drivers' skills and habits can raise or lower fuel economy by as much as 30 percent.
Decker has gained some hauling business from shippers tuned into the green movement and seeking carriers whose executives are of like mind, Lursen says. Truck operators interested in trying biodiesel should know that diesel makers have formally approved use of blends up to B5, and some will OK the use of higher blends, up to B20. But users are advised to get formal approval from their engine manufacturers before using biodiesel.