A sound by any other name…

Timlynn Babitsky | Noise Pollution | Sunday, March 2nd, 2008

by Timlynn Babitsky
“Noise” is definitely in the ear of the listener.  What constitutes “noise” has pretty much shifted with every generation’s music. Ask any parent — what may be soothing rhythms to one can be headache producing racket to another. So, when it comes to the Noise Issue and wind turbines, there is no objective way to measure how upsetting a sound may be to one person and not another. 

Noise was a very serious problem for the wind energy industry back in the 1980s. Some early turbines were so noisy that even from a mile away it was often annoying to hear them. But today, “an operating wind farm at a distance of 750 to 1,000 feet is no noisier than a kitchen refrigerator or a moderately quiet room.” (American Wind Energy Association)

Well-designed wind turbines are generally quiet in operation. When compared to the noise of traffic, trains, aircraft, industrial and construction activities the noise from wind turbines is very low. And since the 1980s, turbine manufacturers have done a great deal to reduce wind turbine noise.

How noisy are wind farms today?
Compared to other types of industrial and commercial facilities, wind farms are very quiet. But their location in rural, rather than more noisy urban areas gives them less ability to blend into the area’s background “white noise.” On the other hand, most wind farms are located where the wind speed is higher than average. High wind itself will mask the sounds of turning blades.

However, if you are looking to site your turbines in hilly terrain where nearby residences are downwind in shallow valleys, dips or hollows, turbine sound may be an issue. Turbine noise may carry further and not have the high wind “white noise” to mask it as you would find on flat terrain. So, choosing the best site for project turbines becomes an even more important issue.

How noisy are small wind turbines?
Small wind turbines tend to be noisier for their size than large turbines. The manufacturer can provide information about its noise levels, based on standard measurement techniques. Most communities have noise ordinances that typically specify an allowable decibel level for noise at the property line nearest to the source. So, again before you launch into a wind project, there is a lot of homework you need to do.

To address “noise issue” resistors, your best bet is to have a noise analysis conducted as early as possible in your project planning.

A noise analysis will assess:

  • Operating sounds of the specific wind turbine that will be used
  • The topography of the terrain where the project will be located
  • The distance to nearby residences from the wind turbine(s) site
  • Where residences are located relative to the wind blowing across the terrain
  • If any residences are sheltered from the wind (and the natural sound it produces)
  • The normally-occurring background noise levels at the site (pre-construction)

“The most common method for dealing with a potential noise issue is to simply require a “setback,” or minimum distance between any of the wind turbines in the project and the nearest residence, that is sufficient to reduce the sound level to a regulatory threshold.” (American Wind Energy Association “noise facts” ).

“In general, wind farms are not noisy, and wind is a good neighbor. Complaints about noise from wind projects are rare, and can usually be satisfactorily resolved.”

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