The real cost of wind energy.

The cost of electricity from wind is about 4 ¢ per kilowatt-hour (kWh) according to M. Z. Jacobson and G. M. Masters' estimate in their Policy Forum "Exploiting wind versus coal" (Science's Compass, 24 Aug., p. 1438), making wind energy competitive with new coal-fired generation. There is a 1.5-¢/kWh federal credit for wind energy producers, and, in addition, consumers are willing to pay a premium for wind. Given this credit, and a conservative 0.5-¢/kWh green power premium (1), one might expect wind producers to break even at ~6 ¢/kWh. If their costs are 4 ¢/kWh, producers should make large profits and wind should dominate new electric capacity. No such boom is observed; wind generates only 0.1% of U.S. electricity and accounts for only 1% of capacity additions in the last 5 years (2). Two factors--transmission and intermittency--raise the real cost of wind and explain the discrepancy between simple estimates of cost and observed installation of capacity.