Fuel Cell Unit Replaces Conventional Generator
FOR RELEASE: January 9, 2003Fuel Cell Unit Replaces Conventional Generator
Unit Enhances Military's 'Silent Watch' Capability
WARREN, Mich. -The 5-kilowatt regenerative fuel cell auxiliary power unit (APU) with its metal hydride hydrogen storage system is a key component of General Motors Corp.'s diesel hybrid military truck for the U.S. Army.
It opens the door to a new world of flexibility and mobility for the military, and provides an important step toward fuel cell commercialization.
Designed and built by GM's strategic fuel-cell alliance partner, Hydrogenics Corp. - which is 24-percent owned by GM, the APU provides a solution for the Army's increasing electrical power needs in the field while enhancing the military's ability to operate undetected by the enemy.
"This military application of fuel cell technology has the potential to demonstrate valuable benefits and capabilities to an organization that relies on the best available technology for mission critical situations," said Pierre Rivard, Hydrogenics president and CEO. "We are confident that our technology will demonstrate its strengths in a compelling manner."
The hydrogen-powered APU produces electricity quietly with a low temperature signature, zero emissions and better efficiency than the conventional generators powered by internal combustion engines, and provides six to 10 times the endurance of battery-based systems of comparable power. The unit is considerably more efficient in cold weather than batteries and eliminates any issues related to toxicity and recycling.
The Army increasingly relies on the operation of surveillance, computer and communications electronics in the battlefield. Typically, the electricity to power this equipment must be provided by either operating the engine or by storage batteries. In a "silent watch" mode, the engine cannot be operated without the vehicle being detected, and battery technology alone cannot provide sufficient energy for the extended operating times required.
The APU also has lower maintenance costs since fuel cell systems have very few moving parts. Internal combustion engines are subject to considerable wear and tear, and require regular operational checks, lubrication and parts replacement.
The APU's design relies on the regenerative, or reversible, properties of proton exchange membrane (PEM) fuel cell technology. While the vehicle is driving, engine-produced electricity operates a PEM electrolyzer unit, which breaks down water into hydrogen and oxygen. The hydrogen is stored in a metal hydride solid material, GM's first application of a solid-state storage device. When the vehicle's engine is off, the hydrogen is combined with oxygen from the air and fed to a fuel cell unit to generate electricity, with water as a byproduct. The water is stored to repeat the cycle.
The storage unit provides enough gaseous hydrogen to operate for three hours at a peak power of 5kw, or five hours at an average output of 3kw. An external hydrogen fuel supply is not required.
Hydrogen for the APU is stored at low pressure and released at low temperature in a metal hydride container. The metal hydride stores about 1 percent hydrogen gas by weight. The hydrogen is stored very compactly in a space smaller than if the hydrogen were liquefied.
In addition, if the metal hydride were punctured, very little hydrogen would be released at ambient temperatures. The combination of compact storage and inherent safety of metal hydride makes this an ideal technology for military applications.
The APU produces DC power to meet the specifications of the particular applications. In the event that the application requires AC power, the unit's power electronics can be designed to offer this. Such design flexibility makes the APU suitable for a broad range of applications, including backup power, auxiliary automotive and marine power, and off-grid solar power storage.
Hydrogenics Corp. , headquartered in Mississauga, Ontario, is a designer and manufacturer of proton exchange membrane (PEM) fuel cell systems for clean power generation.
General Motors , the world's largest vehicle manufacturer, designs, builds and markets cars and trucks worldwide, and has been the global automotive sales leader since 1931. More information on GM can be found at www.gm.com.