Penalties applied to wind farm noise: Current allowable limits, influencing factors, and their development

Expansion of wind energy facilities has been associated with noise complaints, raising questions regarding the suitability of current allowable limits applied to wind farm noise. Applied penalties and limits also differ between and within countries. This paper reviews current allowable limits and penalties for wind farm noise and its characteristics, discusses differences between limits and penalties and potential areas for improvements. Current guidelines differ up to 25 dBA between jurisdictions (range between 35 and 60 dBA based on outdoor L_Aeq). Wind farm noise acoustic characteristics which potentially make it more intrusive and annoying compared to other major environmental noise sources at equivalent sound pressure levels are also considered. Guidelines also vary widely in their treatment of specific noise characteristics and penalties, ranging from 0 to 6 dBA for the same characteristics. Different methodological approaches used to derive penalties and allowable limits, metrics used and methods of assessment and compliance procedures are also discussed. It is also highlighted that allowable wind farm noise limits and associated penalties are often lacking in evidence to support them and remain to be addressed in the future.