Electric Wind : The Whirling Turbines Are Back in Power Picture
As she looks at her computer screen, Jacqui Ryder notices a warning signal. One of the generators has gone off-line. A click of her mouse--a small controlling device--reveals the problem. The wind has fallen below 12 m.p.h. and the machine has ceased producing power.
“No problem,” Ryder said. “We’re picking up the slack with machines from the other end of the ridge.”
Ryder and her colleagues are in an unusual line of work. They operate--or “fly,” as they like to call it--wind turbines from the new computerized control room of Livermore-based U.S. Windpower Inc., the largest American wind energy company and operator of about 4,000 wind turbines.
Most of these modern-day windmills line the hilly, wind-swept ranchlands of nearby Altamont Pass, high above this San Francisco suburb. To motorists on Interstate 580, they are a spectacular sight. Some look like outsized eggbeaters. Others resemble giant fans. Yet for their otherworldly appearance, the high-tech towers represent the densest concentration of wind turbines on Earth.
As their huge blades catch the breezes off the Pacific, they collectively produce as much as 750 megawatts of electricity--only slightly less than what might be expected from a nuclear or fossil-fuel power plant, though without the potential danger of radiation or a whiff of pollution.
A few years ago, the experts were proclaiming the wind industry’s demise. Federal and state tax incentives had expired in the mid-1980s, and many of the original investors and manufacturers, like the Boeing company, fled the field as government research funds for alternative-energy sources dried up.
“We were a very dispirited group,” said Randall Swisher, executive director of the American Wind Energy Assn., a Washington-based trade group. Edgar DeMeo of the Palo Alto-based Electric Power Research Institute, the research and development arm of the U.S. utilities industry, said, “A lot of people thought the wind power industry would disappear.”
Yet wind power has not only survived, as the whirling beanstalks atop Altamont Pass show, it appears to be entering a boom time. Nowhere is this more apparent than in California, which produces 85% of the world’s wind-generated electricity. Its 15,000 wind turbines have a capacity of 1,500 megawatts, enough to meet the electrical needs of a city as large as San Francisco and the energy equivalent of 3.5 million barrels of oil per year. (A megawatt equals a million watts. An ordinary light bulb uses 75 watts.)
Moreover, those figures promise to grow in California and elsewhere in the United States as engineers develop a new generation of more efficient and powerful windmills.
Though wind power seems like the simplest of technologies--a marriage of helicopter-like blades and small electrical generators--early turbines suffered from inadequate engineering and testing and were often poorly located. The machines broke down frequently and fluctuated wildly in output. Utility company engineers understandably worried about the effects of the erratically behaving turbines on power grids. “We’ve had a heck of a research demonstration going on in our back yard in the Altamont Pass,” Carl Weinberg, PG&E;'s manager of research and development, said wryly.
Having absorbed those early lessons, said the wind association’s Swisher, the industry is finally coming of age technologically. One example of its new maturity is U.S. Windpower’s state-of-the-art control room. In operation since last April, it allows controllers to monitor the performance of every one of the company’s turbines at all times, including a new collection of wind plants being built in the Suisan Bay area northeast of San Francisco.
Color-coded screens show not only the location of every tower on the hillsides above the company’s Livermore headquarters, but also such information as local wind speed, the rate at which the blades are rotating and how much power is being generated. When something goes amiss, a red light flashes. If adjustments are required, operators can “feather” the blades (adjusting their angle to the wind for more efficient operation), call up a history of the machine’s performance or shut the turbine down so a field crew of “windsmiths” can make an on-site inspection.
“It’s a very sophisticated control system, better than anything anyone else in the industry has done,” Ilyin said.
Thanks to such improvements, wind-generated electricity is becoming more competitive. It costs less than 7 cents per kilowatt-hour, compared to 5 cents for power from a new coal-fired plant. (A kilowatt-hour represents the use of 1,000 watts for an hour.) Moreover, when potential health costs, acid-rain damage and other harmful effects from fossil-fuel power plants are taken into account, they add hidden costs of 3 to 7 cents per kilowatt-hour, according to a recent European study.
Most turbines being put on-line are relatively small, with triple blades, each about 25 feet long, and a rated output of about 100 kilowatts. Simple in design, they are easy to operate and maintain and don’t make the thumping noises that characterized some of the older, football-field-sized, multi-megawatt turbines built by Boeing in collaboration with NASA and the Department of Energy. (Only one of these behemoths remains in operation, on the island of Oahu in Hawaii.)
While this approach has made today’s machines highly reliable, it has hurt their efficiency. They can operate over only a limited range of wind speeds. When the wind suddenly gusts, the extra rotational velocity must be absorbed by the turbine’s gears to keep electrical output at a constant frequency of 60 cycles per second, matching the frequency of the grid’s alternating current. But the braking puts stress on the drive train, shortening the turbine’s life and wasting potential power.
In a $20-million collaboration with the Electric Power Research Institute and PG&E;, U.S. Windpower is developing a new line of less wasteful variable-speed turbines. These are not only larger in size (54-foot blades) and output capacity (300 kilowatts), but more efficient and should bring the cost down to 5 cents per kilowatt-hour. Earlier this month, Niagara Mohawk Power Corp. of Syracuse, N.Y., joined the consortium.
When the wind kicks up, instead of relying on mechanical braking, the turbine uses the extra rotational energy to produce more power, yet the frequency of the electricity never wavers.
The new machine’s secret weapon is a solid-state power converter. It smoothes out the effects of fluctuating wind currents by temporarily converting the electricity into direct current then converting it back into alternating current of precisely 60 cycles before releasing it to the grid.
When U.S. Windpower begins commercial production of its new model in 1993, there should be no shortage of sites for the machines. At Windpower 90, the industry’s recent gathering in Washington, researchers at the Pacific Northwest Laboratory in Richland, Wash., reported that a dozen states have even higher wind-energy potential than California. Most are in the Midwest, where winds commonly average at least 13 m.p.h., regarded as a minimum for the operation of wind plants.
Indeed, the DOE-sponsored survey found that just a single ridge in southwestern Minnesota could produce as much electricity as all of California’s wind farms. Such studies suggest that the United States might be able to get perhaps as much as 10% of its electricity from the wind even without any great investment in electrical-storage facilities to meet demand when the breezes die down.
But American turbine makers face strong foreign competition. At least half of the machines in Altamont Pass are imports, most of them from Europe, especially Denmark. On the eastern side of the Tehachapi Pass, several hundred new 250-kilowatt single-speed turbines built by Japan’s Mitsubishi Heavy Industries are spinning away. More are on order by San Diego-based SeaWest Inc., operator of the turbines.
Though the U.S. Department of Energy once invested heavily in wind research and development, European governments are currently spending 10 times as much. For fiscal year 1991, the DOE has a wind budget of about $11 million, down from more than $80 million annually a decade ago. Most of the money will go to three centers: Pacific Northwest Laboratory; the Solar Energy Research Institute in Golden, Colo., site of an equipment test facility, and Sandia National Laboratories in Albuquerque, N.M., which has been developing eggbeater-type vertical-axis turbines.
Even if Washington decides to pay more attention to wind and other alternative-energy sources in the wake of Iraq’s invasion of Kuwait and the steep climb in oil prices, some observers are worried that the United States won’t have the scientists and engineers to pursue these options.
“We’ve behaved like ostriches, keeping our heads completely in the sand while becoming more and more reliant on foreign oil,” said Otto Smith, a retired professor of electrical engineering at UC Berkeley who has long campaigned for increased funding for wind power. “Even my department at Berkeley has just about given up any thought of training engineers that could build alternative energy systems.”