Wind Energy Biography: A Review of Wind Turbine Technology and Economics
Wind energy is widely acknowledged as one of the most sustainable sources of electricity: environmental impacts are relatively low, further reductions in production costs are expected, the distribution of global wind resources is diverse, and the potential for market expansion is large. Life cycle greenhouse gas emissions per unit of wind energy are approximately ninety percent less than emissions from conventional fossil fuel power sources, and bird population impacts and of noise pollution have been reduced significantly in recent years. For these and other reasons, a range of policies have been adopted in various countries to promote wind energy development.
A combination of technological improvements, cost reductions, and economic incentives has made wind energy the fastest growing source of electricity, with installed global capacity doubling approximately every three years over the last decade. The state of the art turbine in 1989 was a 300 kW unit with a rotor diameter of 30 meters. By 1999, 1.5 MW wind turbines with 70 meter rotor diameters were available, and today 4 to 5 MW turbines are under development. Total installed global wind capacity was 4,844 MW by the end of 1995, and had increased over threefold to 17,706 MW by the end of 2000 (Ackerman and Söder 2002). Today’s production costs are one-sixth the costs seen in the early 1980’s, averaging around $0.04 to $0.06 per kWh, and production costs are projected to drop to $0.027 to $0.045 per kWh by 2030 (this report).
A variety of technological and economic issues underlie these impressive developments in wind energy. Several extensive reviews of wind energy technology have recently been published and cover these developments from various perspectives. Ackerman and Söder (2002) review recent global developments and major wind power characteristics. A recent book by Manwell, McGowan and Rogers (2002) provides detailed information on the theory and analysis of wind turbine design and operation. An updated version of Hau’s book on wind technology (2000) provides a detailed account of a range of issues, including turbine design, manufacturing and economics.
This report is intended as a general primer on wind energy technology, with a focus on technological characteristics and how they relate to the economics of wind energy. It draws upon the three major sources mentioned above, as well as a variety of additional sources, to provide a concise survey of four wind energy topics: 1) characteristics and extent of wind resources, 2) fundamentals of wind turbine technology, 3) intermittency of wind energy and the roles of transmission and storage, and 4) the economics of wind energy. Within these topics, there is an emphasis on the theoretical aspects of converting wind energy into electricity, was well as subsequent conversion of electricity into hydrogen.