There has been a lot of debate recently about the low-intensity, low-frequency noise created by megawatt class wind turbines. Although a few credible studies have been conducted (and several are still underway), there is still a great deal of uninformed hyperbole flying around on all sides of the issue.
I'd like to see some sanity in this debate, and I'd like the discussion to be grounded in scientific evidence. Without rehashing the entirety of the debate, here are a couple of points that might smooth developer-community relations a bit.
To start with, the noise levels. I live next to a major arterial road, heavily traversed by buses, trucks, the fire department, and the occasional street racer. Noise levels alongside such a road are typically in the range of 60 to 70 dB. This has been routine in cities worldwide for many decades. Megawatt-class wind turbines produce noise levels, at typical listening positions, of 45 dB or so. In other words, traffic is about fifty times louder than wind turbines. Let's keep things in perspective: that crow that was rooting through your garbage this morning was far, far louder than a turbine half a kilometre away. If we are to come up with logical, reasonable policy for wind turbine deployments, hyperbole will not help make a case for stricter development controls and larger setbacks. Yes, low frequencies do carry for longer distances- but there just isn't very much sound energy there, at least not when compared against any of the noise sources encountered in or near a city.
Now, to the wind developers: It's not necessary to go out of your way to upset people. I can think of no case where there would be any legitimate reason to short-circuit the environmental assessment process- indeed, the most well-respected wind companies make a point of being very thorough in their environmental impact studies. The same goes for the public consultation process that forms a part of every major planning decision. Any cost savings from rushing the planning process will, inevitably, be more than counteracted by the ill will created in the community and the resulting opposition to future projects. We don't fully understand infrasound, and surely, adapting development plans to alleviate any potential issues is preferable to dismissing residents' concerns out of hand. A supportive community means good press and political brownie points, making future projects more likely.
As our scientific knowledge of the physiological effects of infrasound grows, we'll eventually be able to make rational, well-informed decisions on turbine setbacks and zoning. Until then, we have to go with the evidence we have- which, by and large, suggests that turbine noise is no more of a problem than any of our other noise sources, and that as long as turbines are kept an appropriate distance (at least several hundred metres, although the exact figure varies) from houses, residents tend not to have any complaints about them.
Shall we step away from the hyperbole, then- on both sides- and stick to the responsible, consultative planning process that has been proven time and time again to serve us well?