April 2003 | 7100 | 0371-2307-MTDC |
Kathleen
Snodgrass, Project Leader
and Longchaw Lee, Project Assistant
Fuel cells hold promise for Forest Service use, especially in areas where commercial electric power is not available. Although solar, microhydro, and wind power are also environmentally attractive energy sources, their use is not practical everywhere. Fuel cells could provide a clean, quiet alternative supply of power where it is impractical to use renewable energy sources. Possible future applications of fuel cells in the Forest Service include providing power for lights, showers, cooking, and computers at remote fire camps, providing battery-type power for portable field equipment, powering water pumps at recreation sites, and even providing electric power for remote ranger stations. The Forest Service Technology and Development Program, along with other agencies and private industry groups, has begun a fuel cell demonstration installation at the remote Big Goose Ranger Station near Sheridan, WY. This Tech Tip is the first of several that will explain how the Forest Service can use fuel cells.
In 1839, Sir William Grove successfully combined hydrogen and oxygen to produce electricity, inventing the first fuel cell. However, with abundant fossil fuel and the invention of the steam engine, fuel cell technology languished until the 1960s, when the U.S. National Aeronautics and Space Administration (NASA) began using the technology. In space, fuel cells were a desirable alternative to dangerous nuclear power, bulky solar collectors, and heavy batteries—and they produced drinking water. Use of fuel cells by the space program caused industry and government to recognize the potential of fuel cells as a clean energy source.
Fuel cells can power a laptop computer or a clock battery, and large units can be combined to produce many megawatts, potentially serving entire cities. A midsize unit (figure 1) could provide electric power and hot water for your home in the not-too-distant future.
Figure 1—Moderate-size fuel cells can provide
continuous or emergency power for homes or businesses.
Fuel cells are similar to large batteries with constant fuel input. They are energy conversion devices that transform energy stored by hydrogen into electricity, heat, and water. Unless fuel cells use pure hydrogen for fuel, they also produce small amounts of carbon dioxide. The fuel cells have no moving parts. Because they do not burn their fuel, fuel cells produce virtually no pollution. Fuel cells convert 30 percent of the energy in their fuel to electricity, compared to just 20 percent for a typical power plant. The heat produced by fuel cells can be used to provide domestic hot water and to heat or cool buildings, raising the total potential efficiency of fuel cells above 80 percent.
A fuel cell is two electrodes sandwiched around an electrolyte (figure 2). Hydrogen fuel is fed to the anode (positive electrode) of the fuel cell. Encouraged by a catalyst, each hydrogen atom splits into a proton and an electron, which take different paths to the cathode (negative electrode). The proton passes through the electrolyte. The electrons create an electric current (generate electric power) as they return to the cathode. Oxygen enters the fuel cell through the cathode, where the electrons are reunited with the protons and combine with oxygen to form water. Most fuel cells use a reformer to extract hydrogen from propane, natural gas, methane, or other fossil fuels.
Figure 2—This schematic drawing shows how fuel cells produce electricity.
The Forest Service, United States Department of Agriculture (USDA), has developed this information for the guidance of its employees, its contractors, and its cooperating Federal and State agencies, and is not responsible for the interpretation or use of this information by anyone except its own employees. The use of trade, firm, or corporation names in this document is for the information and convenience of the reader, and does not constitute an endorsement by the Department of any product or service to the exclusion of others that may be suitable. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.
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