Wind Farm Sound Level Study Assessment

Achievements and Results

-   External study found to have used inappropriate methodology in measuring noise, modeling, and assessing comparisons.

The Problem

Wind energy facilities produce a new and distinctive type of noise that is unfamiliar in rural, mountainous areas where the turbines are often located, especially in the eastern United States. Modern noise pollution concerns were first acknowledged with the creation of the Federal Environmental Protection Agency (EPA) in 1970, and a great deal of noise information has been learned since then.

Post-construction noise evaluations for wind energy sites are rare worldwide, with only a few published studies having been conducted in Germany and Sweden. As wind facilities become increasingly more common, worldwide noise complaints have emerged as one of the dominant wind facility detriments, second only to aesthetics.

UPC Wind Management LLC / Evergreen Wind Power LLC (UPC) constructed and operates a 28-unit wind facility along a hilltop ridge in Mars Hill, Maine. The wind facility generators are GE 1.5sle models, with a nameplate capacity of 1.5 MW each, for a total installed capacity of 42 MW.

Residents living near the turbines filed noise complaints with the State of Maine shortly after only a few of the turbines became operational. Complaints grew as more turbines came on-line.

In response to these noise complaints, UPC volunteered to collect and analyze sound samples over the course of four 24-hour periods. The purpose of the study was to verify the noise, determine its cause, and to confirm whether the facility was operating within the noise constraints as detailed in the approval permit. UPC engaged RSE for this work, the same firm that had conducted a pre-construction noise assessment of the Mars Hill wind facility.

This expert was hired to examine the RSE study and assess its validity.

The Solution

RSE conducted several site location noise measurements and compared those with their original computer model predictions. RSE also compared the noise data to Maine DEP regulations governing noise, as specified in Chapter 375 of Maine Site Location Law, “No Adverse Environmental Effect Standard.”

Their results were published in a document entitled "Sound Level Study Ambient & Operations Sound Level Monitoring," and submitted to the Maine DEP.

Conclusion

While it is beyond the scope of the present report to evaluate the original RSE noise analysis or the derivation of the Maine DEP noise criteria, it is clear from this expert’s reading of the RSE study that the firm utilized a) inappropriate noise measuring methodology, b) inappropriate modeling software, and c) inappropriate assessment comparisons. The expert also found that RSE did not follow Maine DEP procedures when assessing noise at the site.

To see the resume of the expert associated with this case study, see the link below.