Industrial operations have long done just that, but residential or commercial users couldn’t fulfill their needs using the available small power systems: the diesel generators that keep hospitals alive are too loud and dirty for a suburban neighborhood. Solar power keeps getting cheaper, but it can’t always deliver the kilowatts. Not that these technologies were capable of making much difference, since state laws kept most power consumers shackled to their local utility. Deregulation is changing all that, freeing consumers and unleashing a torrent of investment and innovation. The first products of this wave of technology development are clean, quiet and dependable microturbines, developed in the 1960s to provide electric power for air conditioning and circulation systems on aircraft. They descended toward the consumer market in the early 1990s thanks to Rosen Motors, the company created by Compaq Computer cofounder Ben Rosen to build turbine-powered hybrid electric cars.Rosen’s company was ahead of its time, though, and it paid the price, folding in 1997 just before Toyota and Honda rolled out gas-electric hybrids in Japan. Last year, the Japanese auto giants brought hybrids to America, forcing Detroit to lay hasty plans for its own hybrid cars.
Although the company’s automobile venture collapsed, its microturbine power source lives on in another Rosen venture: Chatsworth, CA-based Capstone Turbine. Capstone’s 30-kilowatt microturbine functions just like the several hundred-megawatt natural-gas-fired power plants that prop up the electrical grid. Ignite the fuel (natural gas, gasoline, kerosene-just about anything that burns) and rapidly expanding combustion gases push the turbine blades to spin a rotor and generate electricity. Exhaust from the microturbines contains only about three parts per million of smog-forming nitrogen oxides-about a hundred times less than diesel generators-and virtually no soot.
And the microturbine is ready to go the distance without burning out, thanks to air bearings that float the turbine on a turbulent film of air just two micrometers thick. The air bearings experience no friction and no wear, even at punishing speeds-more than 1,500 revolutions per second in the Capstone turbine-that would burn up lubricated bearings.
Fuel-cell power plants will run even smoother and cheaper because they are solid state: rather than burning hydrocarbons, fuel cells employ steam and catalysts to release the fuel’s hydrogen atoms and strip away its electrons. Eschewing combustion and bypassing mechanics makes this technology clean and efficient: fuel cells running on natural gas release virtually no nitrogen oxide and convert 40 percent of the fuel’s energy into electricity (a third more than the microturbine). Capturing the wasted energy by using the fuel cell’s hot water byproduct to warm a building’s air and water pushes the overall energy efficiency to 80 percent or more.
At least half a dozen types of fuel cells are under development for electrical power generation. The best hope for smaller, more affordable units lies in a light, compact version based on a structure known as a proton exchange membrane. This is a technology for which we can thank the auto industry; Ford, DaimlerChrysler and Toyota are investing billions to make this variety of fuel cell powerful and cheap enough to replace the internal combustion engine (see “Fill’er Up with Hydrogen,” TR November/ December 2000).
As the technology spreads from the auto industry, a host of startups, including Ballard Power Systems of Burnaby, British Columbia, and Plug Power of Latham, NY, are pushing proton exchange membrane technology for stationary power production. The goal is 1- to 15-kilowatt power plants to enable a family to declare independence from the electrical grid; larger units, 60 to 250 kilowatts, would do the same for offices. Though these companies have aggressive marketing plans, reality-in the form of engineering obstacles-has begun to intrude. Plug Power and its marketing partner, General Electric, planned to be the first to market with thousands of residential units this year. Engineering the units for continuous, glitch-free operation is proving to be unexpectedly complex, however, and Plug Power now expects to introduce commercial fuel-cell systems in the first half of 2002.