LOWELL -- State utility regulators on the Public Service Board said Wednesday that Green Mountain Power should have the time to research how to continuously monitor sound from the Lowell wind turbines.
The board also said that complaints by Shirley Nelson about the health impacts of noise from the turbines near her Lowell home cannot be considered as part of a discussion over penalties for noise violations. The board said Nelson's private monitoring results don't meet board standards.
The board is awaiting information from GMP and the Department of Public Service about whether continuous monitoring of sounds from the 21 Lowell wind turbines is financially and physically feasible.
The department wants GMP to pay a penalty for several noise violations last winter that came from selected monitoring of four areas around the turbines. The department wants the PSB to enforce a $56,000 penalty against GMP to be used to do continuous monitoring.
GMP at first resisted the idea of continuous monitoring, but then said it would research the idea.
The board this week said GMP has the rest of the year to do that research.
GMP spokesman Dorothy Schnure said Thursday that the order gives GMP time to do a comprehensive look at monitoring options and to see if other wind projects have tried to do the same kind of monitoring.
The Nelsons wanted GMP to file its research promptly, but the board said GMP needs the time.
Nelson provided a diary of her own observations about turbine noise at her home and how her health and the health of others was impacted. She observed and reported what she saw were violations of the maximum sound level allowed at her home.
The board reacted to the diary in its order Wednesday.
"First, we take the descriptions of project impacts set forth in Mrs. Nelson's diary seriously," the three members of the board stated.
"However, as the department points out, Mrs. Nelson's diary indicates impacts during times when the existing monitoring protocol has confirmed that the turbines are operating below the maximum permissible sound level imposed in the certificate of public good (for the Lowell turbines).
"Additionally, for those instances where monitoring has confirmed violations of the sound standard, the increment of violation has been small enough to be imperceptible by the human ear," the board stated.
"In other words, Mrs. Nelson's complaint appears to be more with the actual sound standard that we imposed in approving the project, rather then the actual monitoring being done to confirm whether or not the project is in compliance with that standard. Shortening the deadline as requested would not address what appears to be Mrs. Nelson's true concern."
The board said it is reviewing whether Lowell turbines have violated noise standards set by the board. The board is not reviewing the sound standards that the board has used for all wind projects in Vermont.
The board indicated that private monitoring is problematic.
"We are also aware of the fact that Mrs. Nelson has obtained and been using a sound meter to take decibel readings of turbine sound levels on a regular basis, and that those readings indicate sound levels at times in excess of the applicable noise standard, including times when GMP is not conducting sound monitoring.
"However, while we appreciate Mrs. Nelson's efforts, the approach does not allow for the elimination of background sound levels to isolate and determine the actual sound levels of the turbines themselves. The sound standard for the project applies to noise from the Project only, not to the total sound level from all sources in the vicinity of receptor locations. As a result, we cannot draw any conclusions regarding project compliance from the information submitted by Mrs. Nelson."
The board, in a footnote, noted that there are "technical issues" with the readings taken by Nelson, which board members stated "render the reliability of the results questionable." Background noise is the most significant of those issues, the board stated.
The board did note that the department has asked GMP to expedite the research and has offered staff time to produce a complete report as soon as possible.
The board has received the summer monitoring report and fall monitoring is underway.
The board is considering an order to have GMP monitor sound before and after the installation of what's called a synchronous condenser, which is intended to stabilize the flow of electricity from the turbines to the grid. That is expected to allow GMP to operate the turbines at a higher capacity, which the Nelsons fear would create even more noise.