Sound propagation from wind power plants. Measurements 1998-1999

Sound level measurements from wind turbines have been carried out during some days in October 1998 and May-June 1999. The studies showed that different weather conditions can make more than 20 dBA changes from one situation to another. It is therefore necessary to include meteorological and acoustical knowledge when deciding how to use land and sea areas in wind energy prospecting. Measurements over water for a distance of 4 km have been made. The representativeness of these levels are not known. Long-term measurements are the only way to determine the sound levels and how usual they are. Such measurements must also validate numerical sound propagation models. Wind energy prospecting should not be done before more knowledge has been achieved about sound propagation from wind turbines