Large wind-turbine projects in the United States wind energy program

Abstract

The technology for large, horizontal-axis wind turbines (100 kW–2500 kW) has been under development since 1973 as a major part of the United States Wind Energy Program which is sponsored by the U.S. Department of Energy. Specific projects are being managed for the Department of Energy by the Lewis Research Center of the National Aeronautics and Space Administration. The objective of the United States Wind Energy Program is to accelerate the development of reliable and economically viable wind-energy systems and enable the earliest possible commercialization of wind power. To achieve this objective requires advancing the technology, developing a sound industrial technology base, and addressing the non-technological i issues which could deter the use of wind energy. Significant advances have been made in the technology of large, horizontal-axis wind turbines since 1973. Technical feasibility has been demonstrated in utility service for systems with a rated power of up to 200 kW and a rotor diameter of 125 ft. (Mod-0A). There appear to be no major feasibility issues to be resolved. The activation of larger prototype units in utility service in 1979 (Mod-1; 2000 kW, 200-ft. diameter rotor) and in 1980 (Mod-2; 2500 kW, 300-ft. diameter rotor) are expected to confirm this assessment. The long-term reliability of wind-turbine systems is yet to be demonstrated. This will require time to accumulate service experience. In addition, machine capital costs must be further reduced through a combination of continued research and technology development and quantity production. The “second-unit” capital costs for large, horizontal-axis wind turbines currently range from about $8000 kW for operational prototype units in the 200-kW class down to approximately $1000 kW for advanced design prototype units in the multi-megawatt range. Current designs of large wind turbines such as the 2500-kW Mod-2 are projected to be cost competitive for utility applications when produced in quantity, with capital costs of $600 to $700 kW . At this level, wind turbines will produce electricity in the range of $0.03 kWh to $0.04 kWh when operated at sites with a mean annual wind speed of 14 mph (at 30 ft.). These machines will be attractive to some utilities, but for widespread use by many utilities, COEs of $0.02 kW to $0.03 kW will have to be achieved. We expect the advanced technology machines to achieve these COEs when produced in quantity and operated at sites with moderate wind speeds (14 mph yearly average). In addition to the projected favorable economics, wind turbines appear to have no significant environmental impacts and use a replenishable, non-polluting source of energy. These features make wind turbines today one of the most attractive potential solar options for widespread utility application.