In the fall of 2012, the Massachusetts Clean Energy Center (MassCEC), in partnership with the Massachusetts Department of Environmental Protection (MassDEP), launched the Research Study on Wind Turbine Acoustics (RSOWTA) to advance the understanding of wind turbine acoustics, taking into account the influence of variables such as turbine size, technology, wind speed, topography, and distance from the turbine. The study will provide a quantitative basis for testing noise evaluation and modeling methodologies and improve wind turbine siting and approval processes. This report describes the methods and findings of the RSOWTA.
In the fall of 2013, as a first step in the process of incorporating the latest research on wind turbine acoustics into policy and regulations, MassDEP formed a Wind Turbine Technical Advisory Group (WNTAG), made up of representatives with technical expertise in wind turbine acoustics and who offer a range of perspectives. The WNTAG provides technical advice to MassDEP on how best to craft effective regulatory and policy responses to wind turbine installations and to possible noise impacts. Members of the group are listed at the WNTAG website. To inform ongoing WNTAG discussions, two interim reports of preliminary RSOWTA findings were shared with the WNTAG:
- Amplitude Modulation. The first interim report (October 17, 2013) uses some of the data collected to evaluate the spectral and temporal characteristics of amplitude modulation with turbines operating and in ambient conditions. The report includes a discussion on how sound meter settings and sampling rates affect the levels reported for wind turbine and ambient sound.
- Sound Modeling and Monitoring. The second interim report (February 26, 2014) focuses on a comparison of sound levels from operating wind turbines with calculations from sound propagation models to help inform and synchronize the pre-construction estimates of wind turbine noise impacts with post-construction monitoring.
This final report provides additional information on the topics addressed in the interim reports and addresses the following additional topics: low frequency sound and infrasound, tonality, meteorological data, and standards analysis.