Thursday, May 12, 2005

Noise level not acceptable

Near Meyersdale in the Allegheny Highlands of southwest Pennsylvania, the wind facility with which Florida Power & Light replaced a forested mountaintop -- without any warning, as they own the land -- has had some troubles.

After Hurricane Ivan washed out roads and overwhelmed silt barriers in nearby towns in 2004, a few people wondered if clearcutting the ridge above their streams had aggravated the effect, since nobody could remember seeing or could find reports of such problems before. From calculations with the loss of absorptive ground cover and trees, they found that runoff from a severe storm would be 1.3 to 3 times what it would be had the ridgetop forest been left untouched.

A Danish worker was killed last fall while making repairs. Apparently nobody thought about locking the blades while he was up in the crane -- when they started turning they knocked the basket (and worker inside) right off. The chairman of the American subsidiary of Vestas (the Danish manufacturer of the turbines) responded, "These things just don't happen." Except they obviously do.

And the noise. A resident whose home is 3,000 feet or a bit closer (over half a mile) to the turbines got an engineer to measure the noise at his house. Over 48 hours, the noise level averaged around 75 dB(A), as described in this letter and shown in this graph (which mistakenly gives the distance as 3,000 meters (3 km) rather than 3,000 feet).

As quoted in the letter, the EPA says that noise above 45 dB(A) disturbs sleep and noise above 70 dB(A) prevents sleep for most people. Every increase of 10 dB is technically a tripling of the noise level and generally perceived as a doubling of loudness. The A scale is weighted for the normal range of audible sound, but many analysts have determined that the C scale should be used for this kind of monitoring, because it includes some of the lower frequencies that are felt more than heard. Lower-frequency sound waves, as well as vibrations through the ground, travel much farther and are more disturbing than noise in the normal range of hearing. Ignoring them, as well as coming to measure sound only at rare moments, has allowed the industry to claim there is no problem even as people who live near the turbines become addicted to sleeping pills.

In Fenner, N.Y., the wind company has bought neighboring homes that people have fled. They have sold them in turn, and the deeds specifically forbid complaints about the turbines. Similarly, leases with landowners to site turbines on their property typically hold the company free from responsibility for a long list of common complaints, even as the same companies deny such problems exist and insist that everyone loves them.

My thanks to Todd Hutzell of Friends of the Allegheny Highlands and Dan Boone, Conservation Chair of the Maryland Sierra Club, for providing much of the information here.

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