Clean Alternative

Fuels: 

Fuel Cells

One in a series of fact sheets

United States 

Environmental Protection 

Agency

EPA420-F-00-037

March 2002

www.epa.gov

Transportation and Air Quality

Transportation and Regional

Programs Division

C L E A

N

A L T E R N A T I V E F U E L S

C L E A N E R A I R

Georgetown University

in Washington, DC, has

successfully developed a fuel

cell that uses methanol—a

fuel derived from renewable

sources and readily available

at a reasonable price. Granted money in 1991 from the

U.S. Federal Transit Administration, Georgetown has

actively researched using

fuel cells in transit buses.

The university has proposed

building eight fuel cell-powered transit buses for

research and testing.

Through this program,

Georgetown has learned

valuable information about

fuel cell technology’s performance and promise. The

university’s research will play

an important role in the

future commercialization of

fuel cell technology for vehicles. 

For more information,

contact James Larkins,

Georgetown’s program

manager, at (202) 687-

7361.

F

rom midsize passenger vehicles to large transit bus fleets, fuel

cells offer a promising new source of clean power for electric vehicles. This innovative technology uses chemical energy rather than

combustion to generate electric power, resulting in far fewer emissions. In

addition, fuel cell vehicles can utilize renewable fuel and are expected to provide a wider driving range than today’s battery-powered electric vehicles. At

least seven types of fuel cells are currently being researched (see box).

Fuel cells generate power through an electrochemical process, much like a battery.

They convert chemical energy to electrical

energy by combining hydrogen from fuel

with oxygen from the air. Hydrogen fuel

can be supplied in two ways—either

directly as pure hydrogen gas or through a

“fuel reformer” that converts hydrocarbon

fuels such as methanol, natural gas, or

gasoline into hydrogen-rich gas.

Three major U.S. manufacturers and several European and Japanese manufacturers

are actively researching fuel cell transportation technologies and testing prototype passenger vehicles. Several North

American cities are also testing fuel cellpowered transit buses. There are no fuel

cell vehicles currently available for sale in

the United States, but one major U.S.

automaker has announced plans to make

40,000 fuel cell vehicles available for purchase by the general public by 2004. At

least four other manufacturers also plan to

market fuel cell vehicles that year.

Providing fuel to power these vehicles

presents several challenges. Large investments are required to establish hydrogen

production facilities and a convenient

hydrogen distribution system to serve the

general public. As an alternative, manufacturers are working to improve fuel reformers to allow fuel cell vehicles to use

conventional fuels, which would 

encourage consumer acceptance of this

technology.

Actual emissions will vary with 

engine design.

• Fuel cell vehicles operating on

hydrogen or methanol can achieve

zero emission vehicle levels.

• Fuel cells operating with a fuel

reformer emit water vapor, carbon

dioxide, and hydrocarbon emissions.

* Estimates based on fuel cell’s inherently

“cleaner” properties.

*
There is no data currently available

on fuel cell vehicle costs because the

vehicles are not yet commercially

available. Vehicle costs are expected

to vary depending on the fuel cell

technology used and the scale of

vehicle production. Fuel prices also

will vary. Though hydrogen derived

from natural gas is more expensive

than conventional fuels, vehicles

fueled by hydrogen achieve greater

fuel economy. Keys to making these

vehicles cost-competitive include

providing low-cost, high-volume

manufacturing processes, as well as

lightweight, compact, and affordable

hydrogen storage systems.

Because the technology is still under

development, fuel cell vehicles’ performance has not been well-studied

or documented. Based on available

research, fuel cell vehicles are expected to offer an extremely quiet ride

with little vibration. Compared with

conventional vehicles, fuel cell vehicles are also expected to provide

improved fuel economy, increased

engine efficiency, lower smogforming emissions, and reduced

greenhouse gas emissions.

Safety issues vary depending on the

specific fuel source used. Although

most fuel cells, fuel reformers, and

fuel storage systems are not heavier

than conventional systems, some may

be. For such systems, the added

weight can make stopping the vehicle

more difficult. The onboard fuel

reformers also present unique safety

concerns—some reformers can generate internal temperatures up to

1,000°C and produce steam or steam

fuel mixtures at very high pressures.

For More Information

EPA Alternative Fuels Web Site

www.epa.gov/otaq/

consumer/fuels/altfuels/

altfuels.htm

Fuel Cell Institute

P.O. Box 65481

Washington, DC 20035

Phone: 301 681-3532

Fax: 301 681-4896

Alternative Fuels Data Center

Web site: www.afdc.nrel.gov

National Alternative Fuels

Hotline

Phone: 800 423-1DOE

2 Printed on paper that contains at least 30 percent postconsumer fiber.

Types of Fuel Cells

All fuel cells contain two electrodes—one positively and one negatively charged—with a substance that conducts

electricity (electrolyte) sandwiched between them. Fuel cells can achieve 40 to 70 percent efficiency, which is substantially greater than the 30 percent efficiency of the most efficient internal combustion engines. The following

are different types of fuel cells:

• Phosphoric Acid—The most commercially developed fuel cell, generates electricity at more than 40 percent

efficiency.

• Proton Exchange Membrane—Considered the leading fuel cell type for passenger car applications, operates at

relatively low temperatures and a high power density. 

• Molten Carbonate—Promises high fuel-to-electricity efficiencies and the ability to utilize coal-based fuels. 

• Solid Oxide—Can reach 60 percent power-generating efficiencies and be employed for large, high-powered

applications such as industrial generating stations.

• Alkaline—Used extensively by the space program, can achieve 70 percent power-generating efficiencies, but is

considered too costly for transportation applications.

• Direct Methanol—Expected efficiencies of 40 percent with low operating temperatures; able to use hydrogen

from methanol without a reformer.

• Regenerative—Currently being researched by NASA; closed loop form of power generation that uses solar

energy to separate water into hydrogen and oxygen.