Energy | Ecotrope

Wind energy: The noise and the "hush money"

Ecotrope | Nov. 11, 2010 8:20 p.m. | Updated: Feb. 19, 2013 1:44 p.m.

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Think Out Loud is making noise about wind energy this morning on OPB Radio. I'll be on the show talking about why Oregonians are split on whether the state needs more wind farms. What do you think?

Think Out Loud is making noise about wind energy this morning on OPB Radio. I'll be on the show talking about why Oregonians are split on whether the state needs more wind farms. What do you think?

As Oregon has become a national leader in wind-energy production, the regional voices of opposition to wind power have gotten louder.

Oregonians’ complaints about wind-turbine noise and the offer of “hush money” from Caithness Energy, for example, have been heard across the country, thanks to this story and others in The New York Times.

The Times confirmed in August that Caithness had offered landowners near its Willow Creek wind farm in eastern Oregon $5,000 if they sign a waiver promising not to complain about excessive noise from wind turbines. The story didn’t say how many people are being offered this deal now that the New York company is proceeding with the adjoining Shepherd’s Flat Wind Farm – on track to be the largest in the world.

Two perspectives on the money offer from locals, as reported by NYT:

  1. “Shall we call it hush money?” said one longtime farmer, George Griffith, 84. “It was about as easy as easy money can get.” Mr. Griffith happily accepted the check, but not everyone is taking the money.
  2. “The lady that came said everyone else signed,” said Jarrod Ogden, 33, a farmer whose house would be directly opposite several 300-foot turbines once Shepherd’s Flat is completed. “But I know for a fact that some people didn’t. I’m all for windmills, but I’m not going to let them buy me like that. I think they’re just trying to buy cheap insurance.”

Wind-energy opponent groups want to use Oregon’s noise ordinance to get companies to the bargaining table, and neighbors are taking their complaints to county governments in an effort to get the companies to turn down the volume.

DEQ said the noise ordinance – which allows for wind-turbine noise to exceed an area’s ambient noise level by only a certain amount – is on the books but not being enforced by the state on the ground.

“We have the regulations still on the books, and entities are expected to comply with those regulations,” said William Knight, a spokesman for the Department of Environmental Quality. “But there really isn’t anybody from D.E.Q. going around to find out if that’s occurring. I’m not sure who you’d call out there in Columbia Gorge.”

Brian Keane at Grist put together this explanation of how wind turbines are not that loud compared with other noises we hear everyday in response to another story in the New York Times about complaints from wind-farm neighbors in Maine:

“Large turbines like the ones in Maine emit collectively, from a distance, around 45 decibels at their top rotational speed, which they reach in winds upwards of 12 to 15 miles per hour. Typical residential-size wind turbines, whose blades are approximately 6 feet long, are actually louder — 57 decibels at maximum rotational speed, which they achieve in a wind of about 28 to 30 miles per hour — than the big guys. This is because smaller turbines usually spin faster.

So what does this mean? It means that in order for turbines to be making the most noise, the wind has to be blowing hard enough to be nearly as noisy as the turbines. In the wind industry, the turbine noise being washed out by the ambient sound of the wind is referred to as “masking.”

Now let’s put this into perspective. A dishwasher emits about 60 decibels. Imagine you are standing in front of your dishwasher while it is running. Now move away from it. The sound diminishes. Now imagine that on the scale of large wind turbines, located outside, on towers over 200 feet high, surrounded by all of the other naturally occurring sounds in the immediate environment. Even accounting for the subjectivity of individual reactions to sound, it just doesn’t seem quite so offensive now, does it?”

Along those lines, yet another story on the issue in the New York Times reported information from the Acoustic Ecology Institute suggesting only about a dozen of the 250 new wind farms that have come online in the last two years have generated significant noise complaints.

One of the key takeaways from all this is that wind companies can dial down the volume of noise from wind turbines by reducing the speed at which their blades are turning. But the industry doesn’t always want to do that because it means a loss in power generation and higher power costs.

The American Wind Energy Association has a fact sheet on noise associated with commercial-scale wind farms that explains where the noise is coming from:

“The sounds emitted from wind turbines can be mechanical, from internal equipment such as the gearbox or yaw drive, or aerodynamic, from air moving past the rotor blades. Current turbine designs effectively reduce mechanical sound through sound proofing; therefore, the aerodynamic sound, often described as a “whooshing” sound, is what can normally be heard. The aerodynamic noise is present at all frequencies, from the infrasound range over low frequency sound to the normal audible range.”

AWEA convened a scientific review panel last year to look at noise issues, and based on that analysis has concluded:

“Wind plants are always located where the wind speed is higher than average, and the background sound of the wind itself will often “mask” any sounds that might be produced by operating wind turbines - especially because the turbines only run when the wind is blowing.”

There are some who argue requiring bigger buffers around wind farms would help reduce noise impacts on the neighbors, and there are sound dampening systems in the works that should help reduce noise with less power generation lost.

Beyond that, maybe $5,000 per neighbor will silence the debate. Of course, there are still some people worried about the potential problems with turbine noise that we can’t hear. But that’s a whole other story

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