IHT : Wind Energy Unreliable

Friday, December 29, 2006

Wind, almost everybody’s best hope for big supplies of clean, affordable electricity, is turning out to have complications.  Engineers have cut the cost of electricity derived from wind by about 80% in the last 20 years, setting up this renewable technology for a major share of the electricity market. But for all its promise, wind also generates a big problem: Because it is unpredictable and often fails to blow when electricity is most needed, wind is not reliable enough to assure supplies for an electricity grid that must be prepared to deliver power to everybody who wants it — even when it is in greatest demand.  In Texas, as in many other parts of the country, power companies are scrambling to build generating stations to meet growing peak demands, generally driven by air-conditioning for new homes and businesses.  But power plants that run on coal or gas must “be built along with every megawatt of wind capacity,” said William Bojorquez, director of system planning at the Electric Reliability Council of Texas, a power grid that covers most of the state.  The reason is that in Texas, and most of the United States, the hottest days are the least windy.  As a result, wind turns out to be a good way to save fuel, but not a good way to avoid building plants that burn coal.

…..Frank Prager, managing director of environmental policy at the company, said that the higher the reliance on wind, the more an electricity transmission grid needs to keep conventional generators on standby — generally low- efficiency plants that run on natural gas and can be started and stopped quickly.  He said that in one of the states the company serves, Colorado, planners calculate that if wind machines reach 20% of total generating capacity, the cost of standby generators will reach $8 per megawatt hour of wind.  That is on top of a generating cost of $50 or $60 a megawatt hour, after including a U.S. tax credit of $18 per megawatt hour.  By contrast, electricity from a new coal plant currently costs in the range of $33 to $41 a megawatt hour, according to experts.  That price, however, would rise if the carbon dioxide produced in burning coal were taxed, a distinct possibility over the life of a new coal plant.

Without major advances in ways to store large quantities of electricity or big changes in the way regional power grids are organized, wind may run up against its practical limits sooner than expected.  At a recent discussion of clean energy technologies at General Electric’s research center in Niskayuna, New York, Dan Reicher, an assistant secretary of energy for conservation and renewable energy in the administration of President Bill Clinton, predicted that renewables, led by wind, could reach 20% of demand in the next decade or two…..But Reicher drew a quick response from James Rogers, chief executive of Cinergy, one of the nation’s largest utilities, and chairman of the Edison Electric Institute, the industry’s trade association. “I love his optimism,” Rogers said. “But unfortunately, I have to deliver electricity every day.”  Rogers said that wind and another big renewable source that is available only when nature cooperates, solar power, would be necessary because the government would eventually regulate carbon emissions from coal-fired power plants…..The economics of wind would change radically if the carbon dioxide emitted by coal were assigned a cash value, but in the United States it has none.  Coal plants produce about a ton of carbon dioxide each megawatt hour, on average, so a price of $10 a ton would have a major impact on utility economics.  Another possibility is energy storage, although this presents other difficulties.

Reference : http://www.iht.com/articles/2006/12/28/business/wind.php

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