Wind turbines: How loud is too loud?

EAST LANSING, MI—Wind power is among the most frequently cited alternative sources of energy. And, to be sure, advocates for wind power have some good arguments on their side. It is a proven technology that has been providing energy for decades. It doesn’t generate materials that pollute the air, water, or soil. And the wind is a truly unlimited resource.

However, like every other energy source yet found, wind power has its problems. Perhaps the most troublesome of these is the roar created by the turning of the blades of a giant wind turbine.

That’s why a pair of Michigan State University (MSU) professors with expertise on the effects of noise were called on to help prepare a report examining the main issues related to wind turbine.

In their report, issued June 28, 2011 (which is available in full at www.oem.msu.edu/userfiles/file/Resources/WindandHealthReport.pdf), Dr. Ken Rosenman and Dr. Jerry Punch called on the State of Michigan to impose stricter regulations on noise levels than had been recommended 3 years ago.

Rosenman, who is chief of MSU’s Division of Occupational and Environmental Medicine in the College of Human Medicine, said “We strongly recommend [that] Michigan consider our recommendations in revising its 2008 guideline on the placement of onshore wind turbines. We believe wind turbines will benefit our state by offering a viable source of alternative energy, but the public must be protected from risks to safety and health.”

 

LOWER NOISE LIMITS URGED

Specifically, the new report calls for noise levels not to exceed 40 dB, as compared to the 55 dB currently recommended.

“A level of 55 dB or higher presents unacceptable health risks,” said Rosenman, citing research from the World Health Organization that found repeated exposures to a level of 40 dB at night led to long-term adverse health effects such as cardiovascular disease, while shorter-term exposures are associated with sleep disturbances.

The report also sets guidelines on how to measure noise levels and calls for a minimum distance from each turbine to the nearest residence or residential property line to provide adequate safety in the event of falling towers, blade failure, or ice throw.

However, noted Punch, a retired professor of audiology in the MSU Department of Communicative Sciences and Disorders, “It can’t be assumed that distances that protect against physical safety are adequate to protect against annoyance and sleep disturbance from noise.”

The report also recommends several ways for municipalities to minimize complaints and disputes regarding wind turbines, including a mediation process as an alternative to litigation and “good-neighbor” payments to residents within pre-determined distances of wind turbines.