by other energy sources, and on a more complete understanding of the environmental and economic effects of all other available energy sources. LCA can be used to help fulfill that need.

  • Projections for future development of wind-powered electricity generation, and hence projections for future wind-energy contributions to reduction of air-pollutant emissions in the United States, are highly uncertain. However, some insight can be gained from recent model projections by the U.S. Department of Energy. Estimates for onshore installed U.S. windenergy capacity in the next 15-year range from 19 to 72 GW, or 2 to 7% of projected U.S. installed electricity-generation capacity.5 In part because the wind blows intermittently, wind turbines often produce less electricity than their rated maximum output. On average in the MAH, the capacity factor of wind turbines is about 30% for current technology, forecast to improve to near 37% by the year 2020. The projections the committee has used in this chapter suggest that onshore wind-energy development will contribute about 60 to 230 billion kWh, or 1.2 to 4.5% of projected U.S. electricity generation in 2020. In the same period, wind-energy development is projected to account for 3.5 to 19% of the increase in total electricity-generation capacity. If the average turbine size is 2 MW—larger than most current turbines—between 9,500 and 36,000 wind turbines would be needed to achieve that projected capacity.

  • Projections for future wind-energy contributions to air-pollution emissions reductions in the United States also are uncertain. However, given that current and future regulatory controls on emissions of NOx and SO2 from electricity generation in the eastern United States involve total caps on emissions, the committee concludes that development of wind-powered electricity generation using current technology probably will not result in a significant reduction in total emission of these pollutants from EGUs in the mid-Atlantic region. Using the future projections of installed U.S. energy capacity by the U.S. Department of Energy, we further conclude that development of wind-powered electricity generation probably will contribute to offsets of about 4.5% in emissions of CO2 from electricity generation sources in the United States by the year 2020. In 2005, emissions of CO2 from electricity generation were estimated to be 39% of all CO2 emissions in the United States.

  • Although the wind resource in the MAH is closer to electricity markets and transmission lines than much of the wind resource in the United

5

There was no installed offshore wind-energy generating capacity in the United States as of mid-2006, although several projects have been proposed and at least two projects are currently in the permitting stage of development. Department of Energy projections for total installed offshore wind capacity in the next 15 years range up to 12 GW.



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