Power Systems in Vancouver, BC, has for several years been developinga lightweight fuel cell, the "proton-exchange membrane" (PEM) type. In place ofphosphoric acid, PEM cells employ a thin polymer membrane as their electrolyte. By mid-1997, Ballard planned to launch a pilot fleets of a fuel cell-powered passenger buses inVancouver and Chicago. The U.S. Department of Transportation is also developing fuelcell buses. When portability is not an issue, as it is not for municipal utilities, otherpossibilities open up. "Molten carbonate" and "solid oxide" fuel cell technologies, forinstance, could bring extraordinary efficiencies to power-generating stations. Thesedevices run at far higher temperatures than PEM or phosphoric acid cells. Moltencarbonate and solid oxide cells might be able to achieve an impressive efficiencies of 55percent or more, according to Robert R. Rose of Fuel Cells 2000, an advocacy group. The hot steam and carbon dioxide they produce can be used to drive a gas turbine thatgenerates additional electricity, an approach that could push their efficiency to an unheard-of 80 percent. They are potentially up to twice as efficient as a typical oil or coal-firedplant (Scientific American).Energy Research Corporation (ERC) in Danbury, Conn., has built a two-megawattpilot molten carbonate plant for the municipality of Santa Clara, Calif. The fuel cells run atabout 650 degrees Celsius (1,200 Fahrenheit) and consume hydrocarbon fuel that is re-formed into hydrogen right inside the cells. Problems with electrical shorts within the cellshave restricted the plant's output so far to about one megawatt. As the ERC's William V.Baker is at pains to point out, however, that still makes the Santa Clara plant the highest-powered fuel cell unit in the U.S. The company is currently developing a modified designrated at 2.85 megawatts (Scientific America).Future.Although no one can tell the future of fuel cells, you can tell what dire...
