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22 April 2005
Wind Power World’s Fastest-Growing New Electricity Source
Financial incentives, technology critical for further development
Energy issues are critical to earth's environment. This article is part of a series of articles on renewable energy, an increasingly promising element in future energy calculations.
Washington -- Wind power, the technology of using the wind to generate electricity, is the fastest-growing new source of electricity worldwide. Continuing this trend requires aggressive research and development, experts say, and government commitment to giving the technology an economic foothold.
The modern age of wind power arose in the late 1970s and the first wind plants began to appear in California in the 1980s. Today, the industry is growing at 20 percent to 30 percent annually worldwide, said Charles McGowin, wind-power technical leader at the Electric Power Research Institute, an independent, nonprofit center for public-interest energy and environmental research.
“It’s growing because it’s become the most economical renewable energy resource as a result of the large growth in the market,” he said.
“In the 1980s, wind cost about 40 cents per kilowatt hour,” said Robert Thresher, director of the U.S. Department of Energy National Wind Technology Center at the National Renewable Energy Laboratory (NREL) in Colorado. “Now the cost is between 4 [cents] and 6 cents per kilowatt hour, so we’ve reduced the cost of wind by an order of magnitude in the past two decades,” putting it in a competitive range with some conventional technologies.
WIND-POWER TECHNOLOGY
Wind energy is produced mainly by massive three-bladed wind turbines that sit atop tall towers and work like fans in reverse. Rather than using electricity to make wind, turbines use wind to make electricity.
Wind turns the blades and the blades spin a shaft that is connected to a generator; the spinning produces electricity. Industry-scale turbines for utilities are capable of generating from 750 kilowatts to 1.5 megawatts. Homes, telecommunications dishes and water pumps use single small turbines that generate less than 50 kilowatts.
The three-bladed wind turbines operate upwind -- with the blades facing into the wind. Another common wind turbine type is a two-bladed, downwind turbine.
Thanks to research and development, wind turbines have changed considerably over the past two decades.
“The rotor [blades and hub] diameter in 1984 or 1985 was on the order of 20 meters,” Thresher said. “Now, the rotor diameter is on the order of 100 meters, so we’re talking about rotating blades that [cover an area] the size of a football field. The span of today’s wind turbine is bigger than the wingspan of a 747 [aircraft].”
In wind plants or wind farms, groups of turbines are linked together to generate electricity for the utility grid. The electricity is sent through transmission and distribution lines to consumers.
WIND-FARM DEVELOPMENT
The best places to locate wind plants are areas that have strong, frequent winds. For areas around the world, NREL produces wind maps that incorporate wind speeds based on measurements taken over the course of the year at monitoring stations and on estimates from meteorological models.
For specific locations, annual average wind speed is used to calculate the amount of energy in the wind blowing through a wind turbine's rotor per square meter of area. From this calculation of energy available in the wind, geographic areas as small as one square mile are assigned a wind power class from 1 to 7, with 7 being highest. Developers use this information to find the best areas for wind development.
Sites in Wind Power Class 3 or higher are candidates for wind-farm development. Class 2 sites or higher offer possibilities for adding small wind generators.
Wind maps also are being created by the United Nations. The Solar Wind and Energy Resource Assessment (SWERA) is a four-year-old project to map the solar and wind resource of 13 developing countries. So far, the survey has discovered thousands of megawatts of new renewable energy potential in Africa, Asia and South and Central America.
According to a United Nations press release, the U.N. Environment Programme is coordinating SWERA on behalf of more than 25 institutions around the world.
Results of the mapping project have prompted action in several countries, including Nicaragua, Guatemala and Sri Lanka. In Ghana, more than 2,000 megawatts of wind energy potential were discovered, mainly along its border with Togo.
SWERA also has carried out surveys in Bangladesh, Brazil, China, Cuba, El Salvador, Ethiopia, Honduras, Kenya and Nepal. SWERA partner institutions in the United States include NREL and NASA.
GROWING INTERNATIONAL POPULARITY
As an industry, wind power is also growing internationally, McGowin said. The leading wind turbine manufacturers are in Denmark, and there are manufacturers in India, Germany, Spain and Japan.
In terms of installed wind power, he added, “Germany by far has the most -- 17,000 megawatts, of a total worldwide installed capacity of more than 47,000 megawatts.” “Spain is number two and the United States is number three.”
NREL's Thresher said the Kyoto Protocol – an international agreement among 141 countries to reduce emissions of carbon dioxide and five other greenhouse gases – is driving the use of wind energy in European countries, where governments are subsidizing the increase in installed wind capacity.
The Kyoto Protocol, an amendment to the U.N. Framework Convention on Climate Change, came into force February 16. The United States is not a signatory to the protocol.
In the United States, Thresher said, the installed capacity of wind energy is 6,700 megawatts out of a total U.S. demand for electricity of 800,000 megawatts.
“Today,” he said, “wind supplies less than one half of 1 percent of the country’s electricity needs. In comparison, Denmark gets about 20 percent of its electrical energy from wind, and Germany gets something on the order of 6 percent.”
OFFSHORE SITING
All European countries have some installed wind capacity, he added, but some are running out of room for land-based turbines.
“Now they’re starting to move wind turbines offshore. In the European Union, the current plan is to install 50,000 megawatts of wind power offshore, in shallow water, by 2025.”
Offshore wind turbines, now in the early stages of development, are more expensive and harder to install and maintain than turbines on land. Offshore turbines must be stabilized to survive waves and weather, and protected against the corrosive environment. Two advantages of offshore installation are that offshore turbines can be made bigger than those onshore to produce more power per turbine, and the ocean location provides a greater amount of wind.
The United States has no installed offshore wind power but two projects are in the planning stages along the northeast coast. Testifying before the U.S. Senate Committee on Energy and Natural Resources April 19, Thresher said that developing offshore wind energy technologies potentially could provide up to 70,000 megawatts of wind power to the electric grid by 2025, nearly 10 times the current level.
Around the world, he said, about 600 megawatts are installed offshore, and no offshore turbines are installed in waters deeper than 20 meters. A research and development program could help provide access to deeper waters by creating floating platforms for wind turbines similar to the platforms used for offshore rigs.
The goal of such a program, he said, would be to achieve a wind-energy cost of 3 cents to 4 cents per kilowatt hour by 2020.
“Right now, wind energy costs for a typical site are 4 [cents] to 6 cents per kilowatt hour,” Thresher said. “That doesn’t sound like much because the average price of electricity in the United States is about 8 cents per kilowatt hour, and that includes the generation equipment and the cost of fuel.”
Feedstocks for electricity generation can be fossil fuels such as petroleum products, nuclear sources, coal or natural gas, or renewable sources such as hydropower and wind, or a combination of these, depending on a plant’s geographical location.
A problem with wind power, Thresher said, is that wind is an intermittent source, so turbines are not always dependable power sources.
“For the wind turbine to be cost effective,” he said, “it must be cheaper than the price of fuel alone,” he said. In the United States, “hydropower is very cheap – 3 [cents] to 4 cents per kilowatt hour. Coal is probably on the order of 2 [cents] to 3 cents per kilowatt hour. Natural gas is more like 5 [cents] to 6 cents per kilowatt hour, so right now wind is only competitive with natural gas at today’s natural gas prices.”
IMPORTANCE OF U.S. TAX CREDITS
Wind power only can be competitive, Thresher explained, if a production tax credit (PTC) is available for those in the wind-technology industry. Such a tax credit – of 1.9 cents per kilowatt hour -- is in force now in the United States but is slated to expire December 31.
“When the production tax credit is in force,” he said, “wind goes ‘gangbusters’ because people can make money. If the tax credit expires and Congress doesn’t renew it, all the development will stop.”
The situation has created a feast-or-famine market for wind technology in the United States, EPRI’s McGowin said.
“In 2003, 1,600 megawatts were installed in the United States and last year less than 400 megawatts were installed. Congress re-extended the tax credit to the end of 2005, and this year I’m sure more than 2,000 megawatts will be installed.”
In fact, he said, “because of the demand in the United States this calendar year, the entire 2005 production of wind turbines is already sold out. Part of the reason is that the United States does not have a consistent policy on tax credits for wind and other renewables.”
At the National Wind Technology Center, Thresher said, the goal is to perfect wind turbines and bring the cost of wind power down to 3 cents per kilowatt hour over the next 10 years for moderate (Class 4) wind sites where winds are measured 10 meters above the ground at about 13 miles (21 kilometers) per hour.
The United States has many such sites, he said. “The United States has an abundant wind resource. We have plenty of windy land and a very rich offshore wind resource.”
Wind does not necessarily blow at the right time or in the right places, Thresher said, “but if you use wind when you can, you’re saving fuel and reducing emissions and greenhouse gases. You’re basically cleaning up the atmosphere when you have the opportunity to use wind,” he said.
Information about the National Wind Technology Center is available at http://www.nrel.gov/wind/.
Information about the Electric Power Research Institute is available at http://www.epri.com/.
Information about SWERA is available at http://swera.unep.net/swera/index.php.
For additional information on renewable energy resources, see Washington File articles on solar energy, hydrogen fuel cells, biomass and green power marketing.
