The United States Army Tank-automotive and Armaments Command's National Automotive Center introduced a Class 8 Freightliner truck with a prototype liquid-fueled, roadworthy fuel cell auxiliary power unit (APU) at the Society of Automotive Engineers 2003 World Congress in Detroit MI.
This system uses a Ballard Power Systems fuel cell stack and reforming technologies to generate electricity for onboard demands and power external devices. The 5-kilowatt APU is mounted on the driver's side of the truck. An onboard power management system delivers electricity to the truck's systems or exports it from the vehicle as standard household power. The current APU is fueled with a mixture of methanol and water, and further development will enable it to use ultra-low-sulfur commercial diesel fuel.
On the average, heavy trucks idle 20% to 40% of the time depending on season and mode of operation, using one to two gallons of fuel an hour. A single idling vehicle can easily consume more than 2,000 gallons of fuel in a year. The fuel cell APU is expected to reduce that usage, while reducing emissions and noise.