Environmental noise impact of modern wind farms

Electric power production from wind turbines has increased substantially during the past few years due to the growing emphasis on renewable energy sources and more efficient wind turbine technology. Although modern turbines are significantly quieter than early models, wind farms that are proposed near residential areas generate concern about potential noise issues. The present study consists of two parts: (1) the measurement of sound levels within a 2‐km radius of the existing Nine Canyons wind farm near Richland, WA, and (2) the application of an outdoor sound propagation model to predict noise levels, both at Nine Canyons and in the vicinity of a proposed farm near Ellensburg, WA. At most locations within the Nine Canyon site, recorded sound levels were less than predicted levels, with the exception of some downwind sites that were lower in elevation than the source. Noise levels were greatest downwind from the turbines, but never exceeded 50 dBA beyond 500 m from the nearest turbine. In many cases, win...