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Limitations of wind energy concern electricity providers

...because of reliability problems, wind power must be supported by more traditional and reliable sources of generation, such as hydroelectric, coal-fired, nuclear, and natural gas generation. Wind generation is intermittent and sometimes poses challenges to load schedulers who manage the transmission grid systems.

As our country's economy continues to grow, demand for additional supplies of electricity will increase. Energy conservation and new technologies will also play an important role in shaping our energy future.

The different types of additional generation that Montana and our nation should pursue are being debated. Coal supplies about 53 percent of our nation's electricity generation, while nuclear supplies 20 percent, natural gas 16 percent, hydroelectric 7 percent, and petroleum about 3 percent. Wind supplies about 1 percent of our electricity production. In 2005, about 2,500 megawatts of additional wind were added.

Wind has gained popularity as a generating source in part because of the Renewable Energy Production Incentive of 1.5 cents per kilowatt hour (indexed for inflation), that is paid to wind developers for the first 10 years of operation. If the growth in wind generation continues at the same pace as it did in 2005, wind energy will steadily increase its market share. Wind generation has also been helped by a number of states passing legislation requiring a defined amount of production from wind energy. In Montana, the 2005 legislature passed legislation mandating that 15... more [truncated due to possible copyright]  
As our country's economy continues to grow, demand for additional supplies of electricity will increase. Energy conservation and new technologies will also play an important role in shaping our energy future.

The different types of additional generation that Montana and our nation should pursue are being debated. Coal supplies about 53 percent of our nation's electricity generation, while nuclear supplies 20 percent, natural gas 16 percent, hydroelectric 7 percent, and petroleum about 3 percent. Wind supplies about 1 percent of our electricity production. In 2005, about 2,500 megawatts of additional wind were added.

Wind has gained popularity as a generating source in part because of the Renewable Energy Production Incentive of 1.5 cents per kilowatt hour (indexed for inflation), that is paid to wind developers for the first 10 years of operation. If the growth in wind generation continues at the same pace as it did in 2005, wind energy will steadily increase its market share. Wind generation has also been helped by a number of states passing legislation requiring a defined amount of production from wind energy. In Montana, the 2005 legislature passed legislation mandating that 15 percent of a utility's energy purchases come from wind generation by the year 2015.


Back-up generation

Wind energy will play a role in meeting our nation's future energy needs. However, because of reliability problems, wind power must be supported by more traditional and reliable sources of generation, such as hydroelectric, coal-fired, nuclear, and natural gas generation. Wind generation is intermittent and sometimes poses challenges to load schedulers who manage the transmission grid systems. The expected annual electricity production from a wind farm is measured in terms of the turbine's capacity factor when the average annual wind speed is known. A capacity factor between 27 percent and 35 percent is the general industry range. A wind farm with 100 megawatts of generating capacity that has a capacity factor of 30 percent will only produce an average of 30 megawatts of power over the period of one year. Some hours of the day the output will be the full 100 megawatts of power when all of the turbines are performing at optimum performance. However, when some of the turbines are not working or when the wind is minimal, the production output will be something less than the 100 megawatts of capacity. When the wind is not blowing, which can occur during the hottest and coldest days of the year, the production will be zero. Wind advocates promote that a 100-megawatt wind farm that operates at a 35 percent capacity factor produces 35 megawatts of power all of the time. This simply is not the case. In general terms, a wind farm will be producing far less energy then its rated capacity about 65 percent of the time.

Another misconception regarding wind energy is that by increasing its use, we will reduce greenhouse gases. This is only true if wind power is backed up with new nuclear or hydroelectric power or if natural-gas power plants are utilized only for peaking or load-following. When wind power is backed by coal-fired generation, adding wind generation will not reduce greenhouse gases because it will not displace or reduce the production output from the coal-fired plants. This is because wind cannot be relied on as a firm source of capacity output.


Pairing wind, hydro power

Because of the geographical and electrical constraints, along with the characteristics of our nation's transmission system, it is impractical to back up wind power with other wind generation.

If our political leaders were to formulate a long-term plan on reducing greenhouse gases from power generation, the added wind generation, along with other renewable generation and conservation measures, would be backed up with additional nuclear or hydroelectric generation. In fact, hydroelectric generation is the most effective and efficient method of shaping or firming wind power because of the storage capability of the dams.

Because of our nation's vast coal resources, the federal government must also provide the leadership and the research dollars necessary to further develop clean-coal technologies that will produce virtually zero emissions. Wind energy will play an important role in our nation's energy production, but we must be realistic and understand its limitations and challenges.

Terry M. Holzer is general manager of Yellowstone Valley Electric Cooperative in Huntley, which is part of a group of co-ops that has proposed building a coal-fired electricity plant near Great Falls.


Source: http://www.billingsgazette....

MAY 8 2006
https://www.windaction.org/posts/2497-limitations-of-wind-energy-concern-electricity-providers
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