There is no simple solution for state's future electrical energy needs
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No comments [ Add Comment ]By Gary Sandquist
Guest commentary
Is wind power the solution to Utah's future electrical energy needs? For the past century, coal has been the principal fuel for generating electrical power in Utah and much of the West. Coal has been essential for industry, business and residents during this period, and will play a major role in the future as both a fuel and a petrochemical resource. However, with heightened environmental awareness and concern over greenhouse gases and global warming focus is now on alternative energy sources for electrical power including renewables and even nuclear.
Utah consumed 41,300 gigawatt-hours of electrical energy in 2006 for an average annual power consumption of 4.7 gigawatts (GW). About 90 percent of this electricity was produced from coal, 8 percent from natural gas, 2 percent from hydro and less than 1 percent from geothermal, wind and solar.
However, many claim that renewables, probably wind energy, can support Utah's future annual electrical energy growth of 3 percent. This projected growth rate implies a doubling of Utah's electrical consumption from 4.7 to 9.4 GW by 2030.
Let us examine the impacts of generating this additional 4.7 GW from wind energy only. Very large wind turbines (e.g., made by General Electric Corp.) can produce a peak output of about 2 megawatts (MW) at a cost of $1 million. Additional construction, transmission and distribution costs result in a total cost of about $3 million for each turbine. However, the average capacity factor for wind turbine energy generation is less than 30 percent -- accounting for actual average power output for varying wind loading, location, meteorology, and downtime for maintenance and repair. Thus, about 7,800 such wind turbines must be installed to provide 4.7 GW by 2030. The economic cost to rate payers for 7,800 wind turbines at $3 million per unit is $23 billion or $4,900 per kilowatt (KW) of delivered power.
New coal plants carry a projected capital cost of about $1,500 to $2,200 per KW, and new generation nuclear plant costs are estimated at $1,800 to $2,400 per KW.
Of course, the annual cost of fuel must be added to the coal and nuclear plants that could exceed $500 per KW to coal with increased environmental controls, and possible carbon taxes and about $300 per KW for the nuclear fuel cycle including reprocessing or disposal charges. The impact of this wind turbine infrastructure and construction effort is gained by recognizing that these wind towers have 200-foot diameter blades and reach a height of 300 feet above ground. Each wind tower has a profile similar in size to the LDS Church Office Building in Salt Lake City.
Assume these 7,800 wind turbines are distributed along the 300-mile Interstate I-15 that spans Idaho in the north to Arizona in the south, and along the 200-mile Interstate I-80 that spans Wyoming in the east and Nevada in the west. This distribution requires a wind turbine every 400 feet for these interstates.
Furthermore, since wind turbines extract and alter energy from the flowing wind, this corridor of wind turbines, because of turbulence, vortices and other complicated perturbing meteorological conditions, would create an artificial mountain range for wind flow over a mile-wide and 600 feet high along these conjectural interstate corridors.
A very important concern is the impact and consequences of such a major, artificial meteorological disturbance upon seasonal weather and precipitation conditions in Utah. Utah is the second-driest state in the U.S. after Nevada. Average Utah annual precipitation is only about 13 inches and has been declining over the past few years. Furthermore, Utah's water budget depends primarily upon mountain snowpack and water recharge zones located in the Bear, Weber, Jordan, Uinta and Sevier rivers watersheds along the Wasatch mountain range.
These areas are also the best wind resource areas as identified by the U.S. Department of Energy.
The critical, unresolved issue is: How would such a massive topological disturbance affect Utah's water storage economy? It is a well-known meteorological fact that as moisture-laden air is lifted by ground profiles, the temperature in the air mass changes and moisture may be deposited prematurely. The naive answer to locate all wind towers on mountain tops may not be the proper solution to avoid negative impacts on precipitation distribution and deposition for the state.
Furthermore, such remote locations would greatly increase capital, transmission and maintenance costs for the wind towers, and might prove unacceptable from visual impacts. The full impacts upon Utah's water budget, climate changes, electrical utility costs, and reliability and environmental issues of such a massive development of wind energy over the next two or three decades are difficult to assess, but must be evaluated and addressed before implementation. We conduct major environmental impact statement investigations of coal, hydro and nuclear installations before siting these utilities.
Obviously, there are similar and profound questions regarding the massive development of wind power. It should be apparent to Utah residents that there are no simple solutions for Utah's future electrical energy needs. Fossil fuel, renewable (hydro, wind, solar, geothermal), nuclear, and hydrogen production must all be carefully and rationally evaluated.
Sandquist is a professor of mechanical engineering at the University of Utah.
