Seite - 123 - in Water, Energy, and Environment - A Primer

Beyond these numbers, it is important to recognize that wind energy is rapidly becoming a commodity, an unsubsidized technology competitivewith subsidized traditional technologies (fossil fuel and nuclear). It is a plentiful, renewable, widely distributed energy resource that produces no greenhouse gas emissions during operation, consumes no water, and uses relatively small amounts of land. Today, onshore wind is, in many cases, the least expensive of the newsources of electricity generation. Windpower does have negative impacts,which are generally less problematic than those from nonrenewable energy sources. These include the noise generated by whirling wind turbines, the visual impact of largewind structures, bird and bat kills that arise from collisions with turbine blades, and the complications that arise from the fact that wind is a variable resource.While the electrical output from an individual turbine may be relatively consistent from year to year, it can have significant variation over shorter timescales and create problems of grid integration. To address these issues the wind industry has switched from traditional (lattice) support structures to cylindrical supports onwhich birds cannot roost, stoppedwind turbine operations during periods of heavy bat activity, conducted extensive R&D on noise suppression techniques, firmed up wind farm output with backup fossil fuel sources, combined the output from geographically distributed turbine Figure 8.12 Global cumulative installed wind capacity (MW) (Source: GlobalWindEnergyCouncil). Renewableenergy 123