This winter the City of Salem plans to further explore whether placing a wind turbine at Winter Island would cause undue disturbance of neighbors due to the sound of the turbine. Just in time the Mass Clean Energy Center has issued new guidelines for acoustic engineers to ensure studies meet the highest standard. According to the recently released draft document guidance is provided on:
1) determining the ambient sound levels,
2) calculating the hub height wind speeds, and
3) modeling the increase in ambient sound pressure level associated with selected turbine(s) operating at the proposed location(s).
In particular, the methodology addresses the importance of collecting sufficient measurements in a project area to firmly establish the ambient sound levels at wind speeds high enough for the turbine to generate power. For a wind energy project, this task is complicated by the fact that simply measuring the lowest L90 sound level in a given one- to two-day period is insufficient because winds may be too light during that time period for turbine operation.
You can read the revised methodology guidelines here.