Pisgah Mountain Wind Farm is a five-turbine, nine-megawatt wind farm in a rural, mountainous area east of Bangor, Maine. RSG conducted a postconstruction compliance assessment to determine if the sound from the project was within the limits of the town ordinance.

The ordinance had specified methods for sound monitoring and data analysis that required careful planning and consideration for the assessment. RSG conducted continuous monitoring of sound levels at one-third octave bands and at 50-millisecond intervals over approximately 20 days. We continuously collected weather data and audio during the monitoring period. During sound monitoring, the wind turbines were shut down periodically to assess background sound levels. This was done to determine the sound level attributable to just the wind turbines. We determined the wind farm followed the sound requirements of the town ordinance, with measured turbine-only sound levels of approximately 30 dBA. We reached this determination after a detailed time-synchronized analysis of operational sound levels, background sound levels, audio files, meteorological data, and turbine production data.