by Annette Smith, Danby
Prospective neighbors of wind turbines heard all the promises: “Quiet as a library. The same decibel-level as a refrigerator.” More brazen wind developers claimed “you will not hear them.”
Then the 450-foot wind towers with their bus-size (generator housing) and three-bladed fans were built. Sixteen in Sheffield, four on Georgia Mountain, 21 in Lowell. And neighbors learned the truth. Yes, you can hear them. They sound like “a jet plane that never lands,” or “sneakers in a drier,” or there is a “whoosh whoosh whoosh” as the blade passes the tower, causing something called amplitude modulation.
Neighbors talk about feeling a deep rhythmic rumble inside their homes. “We feel the vibrations over the TV set,” they say. That is the low frequency noise.
Some farmers living five miles from the Lowell wind turbines talk about the side of the barn vibrating. (Donald and Shirley Nelson), who had no choice but to sell their farm in Lowell to Green Mountain Power (for $1.3 million) due to their deteriorating health and quality of life, said their windows vibrated, and the vibrations were visible in a bowl of water on the kitchen counter.
Some experience the barometric pressure waves that hit their homes, turning the house into a drum, producing inaudible infrasound inside the home at higher levels than outside. “Imagine you are sitting at your kitchen table and are seasick, except you are not on a boat and nowhere near water,” says one former neighbor whose family became so sick after living 3,500-feet from the wind turbines that they abandoned their home of 17 years.
Infrasound cannot be heard, but it has been scientifically proven by recent studies to be a component of the acoustical profile of wind turbines. The vortexing pressure waves do not dissipate and can go out for miles.
This acoustical profile of wind turbines creates a challenge for regulators and experts they rely on. Typical noise control measures such as insulating the source or insulating the receptor do not work with an open air source and a receptor that experiences higher levels of infrasound inside the home than outside. And people have a right to have their windows open. Insulation does not work.
The noise produced by wind turbines does not create a problem for the wind industry, though. “There are no problems,” is their attitude. “It’s all in their heads,” they say. “The “nocebo effect” is at work,” they claim, alleging that people’s beliefs are making them sick. They heap ridicule on neighbors who are victimized once by the wind turbines themselves, a second time by the industry which refuses to accept responsibility and a third time by regulators who have turned a deaf ear to complaints filed since mountaintop wind turbines began operating.
A unanimous vote by the Vermont House last year affirmed that there is a problem. The legislature directed the Public Service Board to right the wrong.
The board issued a rule that sets a night-time level of 35 audible decibels. This has resulted in a shrill response from wind proponents who claim that this standard would outlaw bird songs.
On wind turbines and decibel levels:
- Nighttime background noise levels in the areas where wind turbines have been constructed are about 20 audible decibels. Ten audible decibels above background results in complaints. The correct standard for wind turbines in the very quiet areas where wind turbines are being built would be 30 audible decibels — lower than the board is proposing.
- The board rule has a 10 times total height setback, or 5,000-feet for 500-foot-tall wind turbines. It may not be far enough, but it is a step in the right direction.
The wind developers have made big promises. Now they have promises to keep — so their neighbors don’t have miles to go before they sleep. And the Vermont Public Service Board should establish standards that reflect those promises.
The writer is executive director of Vermonters for a Clean Environment
Note: Edited for length.