[The following is the electronic edition of _Wind Energy Weekly_, Vol. 12, #544, 4.26.93, published by the American Wind Energy Association. For more information on the Association, contact AWEA, 777 North Capitol Street, Suite 805, Washington, DC 20002, USA, phone (202) 408-8988, FAX (202) 408-8536, email 3304640@mcimail.com] UCS: WIND IS LOWEST-COST RENEWABLE FOR MIDWEST The Union of Concerned Scientists (UCS), a leading environmental organization, recently published a major study, Powering the Midwest: Renewable Electricity for the Economy and the Environment, which concluded that wind energy is among renewable energy technologies holding great promise for the region. This is one of a series of articles reprinting excerpts from the report, by permission of UCS. Wind Energy: Background Winds are created by the sun's heating of the earth's surface and are strongly influenced by local terrain, bodies of water, weather patterns, and other factors. In some areas, like the Altamont and Tehachapi passes in California, where most of the world's windpower development has taken place, winds follow a strong daily cycle created by temperature differences between land and water. In the Midwest, the predominant winds are associated with large-scale air movements driven by the jet stream, although daily temperature-induced effects can be important. Winds also vary with height above the ground. In relatively flat or rolling terrain typical of much of the Midwest, wind speed rises steadily with height . . . Since the 1970s, the wind energy industry has learned an enormous amount about wind turbine design and operation. Initially, federally-funded research focused on very large machines capable of producing one to five megawatts (MW) each. But the high unit costs of these machines and their unsatisfactory performance led to their gradual abandonment (except in Europe, where research continues). Small wind machines of one to 50 kilowatts (kW) peak power, on the other hand, have proven very reliable and now compete in markets for remote power supply worldwide. These machines usually deliver direct current (DC) power for battery charging, water pumping, refrigeration, and other uses. They can also be connected directly to utility girds on the customer side of the meter . . . By far the greatest activity, however, has occurred with utility-scale, intermediate-size wind turbines of roughly 50 to 500 kW peak capacity. This class of machine has accumulated the vast majority of operating experience in the past 15 years. Today there are roughly 2,000 MW of intermediate-size wind generators in operation worldwide, with about three-quarters of this capacity located in California and most of the rest in Denmark. On average, wind energy supplies around one percent of California's electricity demand and 2.5 percent of Denmark's. Among electric utilities, Pacific Gas & Electric (PG&E), one of the largest in the country, uses the most windpower. At peak times during the summer, as much as seven percent of its demand is supplied by wind . . . Although wind turbines appear simple, there are many subtleties to their design that have proved the downfall of more than a few ambitious inventors. Reliability was initially a serious problem, as components proved unexpectedly susceptible to fatigue, vibration failure, and mechanical breakdowns. Instead of the expected 20- to 30-year life spans, some lasted only five years, while operating and maintenance costs were also higher than expected. Incremental improvements over the years have gradually resolved these problems, however, resulting in far more reliable and efficient wind turbines. With more rugged designs, better choice of materials, and more careful attention to maintenance, average wind-turbine availability1 has risen above 90 percent--a level typical of conventional power plants--and mature systems routinely operate 95 to 98 percent of the time.2 It remains to be seen how well existing wind machines will perform in the very cold weather experienced in parts of the Midwest, but there are no technical reasons why high reliability cannot be achieved under such conditions as well . . . The machines in a windfarm must be spaced far enough apart to avoid excessive wake interference between wind turbines. In the California sites that have been developed, winds are largely one-directional, so it is possible to space wind turbines two to three rotor diameters apart in the crosswind direction and five to 10 diameters apart in the downwind direction. In the Midwest, however, wind directions tend to be more variable, so a spacing of five to 10 rotor diameters in any direction is preferred. Based on existing wind turbine designs, this means roughly three to 12 MW peak wind capacity per square kilometer of land area. Only about three to five percent of this land is actually occupied by the wind turbines. 1Availability is the percentage of time that a wind turbine is ready to perform its function. 2See, for example, Jon G. McGowan, "Large-Scale Solar/Wind Electrical Production Systems," in Energy and the Environment in the 21st Century, edited by Jefferson W. Tester, David O. Wood, and Nancy A. Ferrari (Cambridge, Mass.: MIT Press, 1991); and Cavallo, Hock, and Smith, "Wind Energy." [Copies of the executive summary of Powering the Midwest are available for $3 from Union of Concerned Scientists, 26 Church Street, Cambridge, MA 02238, USA, phone (617) 547-5552, fax (617) 864-9405. Copies of the entire study are available for $18 from the same source.] U.S. WINDPOWER TO INSTALL 38 NEW TURBINES U.S. Windpower has received approval to install 38 of its new 33 MVS turbines in the Altamont Pass, according to the trade newsletter California Energy Markets. The turbines, which will replace 131 of the company's older 56-100 model, will be installed by summer 1993 if no objections are filed to the project, U.S. Windpower said. The new installation would be the largest number of turbines expected to be installed in the United States this year. It will also be the largest single project in California using wind turbines greater than 30 meters in diameter. (San Gorgonio Farms is currently operating a total of 40 wind turbines 35 meters in diameter or larger, but in four separate projects.) Originally, U.S. Windpower had proposed to remove the older machines and replace them with 80 units of an early production version of the new 33 MVS design. The proposal was part of a planned effort to study the impact of newer wind turbine designs on birds in the Altamont Pass. Currently the fleet of machines there is among the oldest in California, with technology dating largely from the early 1980s. Few of the turbines running today in the pass are still being manufactured, and U.S. Windpower argued that it makes little sense to test measures for mitigating bird problems with turbines that won't be used in future projects. However, the U.S. Fish & Wildlife Service (USFWS) objected to the proposal, charging that a "study to identify mitigation measures is not in itself a mitigation measure," the article said. It said the energy chair for Sierra Club California, Rich Ferguson, rose to U.S. Windpower's defense, noting that a statistically significant number of turbines is needed to make headway on the problem of wind turbines and raptor mortality. Alameda County limited the number of new turbines based on USFWS testimony that 38 of the new machines were equivalent in rotor swept area to the 131 older turbines being removed. U.S. Windpower's permit brings to 15 MW the amount of capacity that will be installed this year in California. However, only 3.4 MW, from AB Energy's 15 turbines recently installed in Tehachapi, will be added to capacity totals. AWEA SEEKS 150 MW OF WIND IN NEW YORK BY 2000 In comments submitted to the New York Public Service Commission April 12, AWEA urged that state's utilities to set a goal of 150 MW of wind capacity by the year 2000, and to take other steps to "ensure that wind energy will become available as an energy supply option during the next decade." Former AWEA Executive Director Tom Gray presented the comments before an informal "working group" sponsored by the Commission which is discussing implementation of a State Energy Plan goal of 300 MW of new capacity from renewable energy technologies by 1998. Gray noted that a summary of utility research, development and demonstration (RD&D) plans provided to the group by New York's utilities indicated a commitment through 1998 only to 0.7 MW of wind, which consists of two U.S. Windpower turbines that are already under test by Niagara Mohawk Power Co. He said AWEA recommends instead that the utilities acquire at least 30 MW of wind by the end of 1996, in order to develop experience with "issues involving sizable deployment of wind technology, including planning, siting, public acceptance, turbine selection, licensing, permitting, windfarm design and infrastructure expenses, system integration, and other [operations and maintenance] concerns." Department of Public Service staff also recommended an increase in utility wind RD&D. Staff Counsel Paul Agresta urged that five other utilities in addition to Niagara Mohawk install demonstration facilities to gain "hands-on experience" with the technology, and added, "We'd also like to see a windfarm, whether it's carried out by one utility or jointly." The windfarm, he later said, should be at least 15 MW in size. Overall, the Department supported the installation of approximately 100 MW of renewables. Utility spokesmen generally seemed receptive, suggesting that the proceeding will ultimately result in some additional renewable generating capacity, but an amount short of the 300-MW goal. New York's utilities are currently in a position of overcapacity and the state's economy is sluggish, stirring concern about the economic impacts of a more ambitious effort. In addition to its total capacity recommendations, AWEA offered what it described as "an appropriately scaled, balanced wind RD&D and commercialization program for [New York] utilities," including: - Construction of an advanced wind turbine demonstration windfarm, in cooperation with the Electric Power Research Institute and the U.S. Department of Energy, which have announced their intent to fund several such facilities. - An increased program of wind measurement and site selection, to further define the state's wind resources and most promising locations for development. - A program to evaluate and purchase small wind turbines as potentially cost-effective power sources for remote applications. AWEA also backed net billing for wind turbines below 40 kW in capacity. - Establishment of a utility wind group which would share knowledge and information about wind energy installations.