FUEL CELLS—ENERGY FOR A POWER-HUNGRY WORLD - Chemistry: Notable Research and Discoveries - page 153

bining battery power with a small gasoline engine. The resulting car, called
a hybrid electric vehicle (HEV), gets more miles out of a gallon of gasoline
than a conventional automobile, which helps the motorist's finances as
well as the environment. But HEVs are not zero-emission vehicles.
Early versions of fuel cell vehicles have already been built and are being
tested. For example, National Renewable Energy Laboratory (NREL), one
of the U.S. government's leading centers for energy research, is evaluating
fuel cell vehicles deployed at Hickam Air Force Base, in Honolulu, Hawaii.
Scientists at NREL are involved in a large number of projects aimed at re-
searching, designing, and testing a variety of technologies to improve the
nation's energy efficiency. The sidebar on pages 154-155 provides more
details about this important research and development laboratory.
Conservation and energy efficiency is critical at all levels, but the fed-
eral government is the biggest consumer of energy in the United States,
and military operations account for the bulk of this usage—the Depart-
ment of Defense accounts for nearly 80 percent of federal government
energy consumption. Increased efficiency in federal government activi-
ties would translate into big savings. One young airman who worked on
the flight line at Hickam Air Force Base in the 1980s once decided to
conserve fuel by walking out to the airplanes instead of taking a motor
vehicle. His supervisors were favorably impressed with his initiative. his
conservation effort worked out well, until one day when even the young
airman's spry legs almost failed to get him out of the way of a taxiing
KC-35 airplane, the pilot of which was for some reason in a hurry to reach
the hangar. From then on, it was back to the motor vehicles. (But the air-
man, who now has a more sedate job—and is the author of this topic—
continues to walk instead of drive when he can safely do so.)
Two types of vehicle are being tested at Hickam Air Force Base. One
is a 30-foot (9.1-m) bus, used for shuttling passengers around the base,
and the other is a step van to carry packages and equipment (similar to
the vans used by FedEx and UPS). Powering these vehicles are hybrid
engines, consisting of both a battery pack and a fuel cell. The bus has a
relatively small fuel cell stack, capable of generating 20 kilowatts, and
relies more on batteries supplemented by fuel cell energy. But the step
van contains a larger, 65-kilowatt fuel cell system. The fuel cells of both
vehicles are proton exchange membrane cells operating on hydrogen.
To provide fuel, officials built a hydrogen station on the base. This
station consists of a power control unit, a water container, a fuel pro-
cessor that produces hydrogen by water electrolysis, a compressor (to