Regulating and Predicting Wind Turbine Sound in the U.S.

There are very few states with a state-wide noise rule. In the 1980's President Reagan, disbanded the US EPA's Office of Noise Control as noise was determined to be a local land use issue that didn't warrant federal oversight. Thus, the development of noise control regulations falls to a local land use planner. An acoustical professional is not often involved in the development or review of such codes. As such, clarifying terminology is often lacking and seemingly simple plain language may be interpreted to be extraordinarily precise. This paper suggests methods and guidelines for local noise ordinances to avoid potential future confusion. In addition, requirements for the prediction of sound levels from wind turbines are often inconsistent between the various states and local governments that require it. Underprediction of sound levels can lead to potential compliance issues for a wind project, while overprediction can result in projects restricting operations unnecessarily. This paper suggests sound propagation modeling parameters and procedures that are recommended when applying them to noise standards commonly used in the U.S. Real-world post-construction sound measurement programs will be compared to pre-construction modeling using the recommended modeling parameters and procedures.