NREL tests show improvement on fuel economy of heavy-duty hybrid trucks

A performance evaluation conducted by the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) shows significant improvements in the fuel economy of Class 8 hybrid electric tractor trailers, compared with similar conventional vehicles.
“During our 13-month study, the hybrid tractors demonstrated 13.7% higher fuel economy than the conventional tractors, resulting in a 12% reduction in fuel costs for the hybrids,” NREL Senior Project Leader Michael Lammert said.
For more than 10 years, NREL has been tracking and evaluating new propulsion systems in transit buses and trucks. These evaluations are necessary parts of the U.S. Department of Energy’s Advanced Vehicle Testing Activity, which is tasked to conduct comprehensive, unbiased evaluations of advanced technology vehicles operating in fleets nationwide.
In addition to field testing, the NREL team also performed dynamometer testing at its Renewable Fuels and Lubricants (ReFUEL) Research Laboratory. During the testing, the hybrids demonstrated up to a 30% improvement in fuel economy, depending on drive cycle, and up to a 32.1% improvement in ton-miles-per-gallon. The test was conducted on comparable conventional tractors of approximately the same age and operated in similar conditions in the same facility.
“Our analysis identified key variables on trucking routes–such as idle time, kinetic intensity, and average speeds that, if taken into consideration, can help Coca-Cola Refreshments optimize the use of its hybrid vehicles on routes where they offer the greatest fuel economy benefits. We see cost as the number one barrier to companies using advanced technologies. Testing like this helps companies understand whether these vehicles are going to save them money over the long run,” Lammert said. (September 17, 2012)