Recent studies have shown that there is sufficient wind resource in the United States potentially to develop electricity generating capacity roughly equivalent to twice the amount of existing U.S. generating capacity.(1) However, given economics, land use, the intermittent nature of wind energy, and other constraints, the usable portion of this resource is considerably less. Wind energy technology has progressed dramatically from the early days of California wind farms. Largely through a combination of improved design, accumulated operating experience, and better siting, wind turbines have established a track record of solid reliability and declining cost.(2) Yet the integration of wind capacity into electric utility systems continues to be hampered by a number of barriers, including the current and projected low cost of electricity from natural-gas-fired power plants, the intermittent nature of wind, the lack of data on viable wind resource areas, the distance of wind resources from demand centers, relatively high financing costs for wind energy projects, and overall reliability problems for individual utilities as wind capacity begins to increase its share of total generating capacity.