Ontario’s wind-turbine-installing powers-that-be have been trying to convince everyone (and maybe even themselves) that wind turbines do not cause any health problems for those unfortunate to live too close. There are now two major reports being bandied about that try to make that case. First was the report from the Ontario Chief Medical Officer of Health, Dr. King. Second was the Sierra Club’s report, of which I’ll have more to say in a later posting. A key part of the “evidence” they both use is the work of Eja Pedersen, a medical researcher in Sweden. As an example, from the Sierra Club:
In this self-reported study, for levels between 37.5-40 dBA, 73% of respondents noticed the noise of wind turbines while approximately 6% were annoyed. At 40 dBA and above 90% of people noticed the sound while 15% were annoyed. By maintaining the limit of 40 dBA most people will hear the sound of a wind turbine, but very few if any will be annoyed and there are no negative health effects (Pederson, 2008).
Both King and the Sierra Club insist the Ontario limit for noise is 40 dBA, and since Pedersen didn’t find much annoyance at that noise level, therefore Ontario’s limits will protect the neighbors. There’s a number of problems in this chain of logic (which of course I’ll detail below), enough to render the comparison totally misleading.
First let me lay out how Pedersen set up her studies. She located homes where the calculated wind turbine noise would be greater than 30 dBA at several selected projects and from that pool she contacted some portion of the homes asking them about their reaction to the wind turbine noise. She then divided the responding homes by their calculated noise levels into 5 groups and compared their level of annoyance (among other things). As you can imagine, the high-noise groups expressed more annoyance than the low-noise groups did.
One critical point was how she calculated the noise; in particular, at what wind speed the noise calculations were made. Wind turbines make more noise as the wind increases and they produce more electricity until leveling off. In Pedersen’s studies they did the calculations at a wind speed of 8 m/s. Now, 8 m/s is pretty brisk – Beaufort 5, “fresh breeze”, many whitecaps, some spray, small trees swaying. Especially at the defined height of 10 m. The turbine would be pretty loud at that point. So Petersen’s 40 dBA line (relating back to Ontario’s limits) would extend quite far from the turbine, relatively speaking, picking up homes that really don’t get as much noise as you might first expect.
The problem is that Ontario’s wind turbine noise limit is NOT 40 dBA; it is really 51 dBA, depending on wind speed. More specifically, at Pedersen’s 8 m/s the Ontario limit is actually 45 dBA. Ontario’s reasoning (apart from being developer-friendly) is that the noise of the wind itself at that speed will “mask” the noise of the turbine. Ontario is the only remaining jurisdiction in the world to use this logic; everyone else has found that nothing masks a turbine’s noise and has eliminated this loophole.
Perhaps you can now see the problem. King and Sierra Club both use Pedersen’s 40 dBA results and correlate that directly with Ontario’s 40 dBA limit and conclude that there’s not a problem. But Ontario’s rules actually allow an extra 5 dBA. What happens to the complaint/annoyance numbers at 45 dBA? They increase dramatically, somewhere off the end of this Pedersen annoyance curve:
If that extra 5 dBA were applied in the other direction, Ontario’s noise limit would be 35 dBA and we likely wouldn’t be having this discussion, as setbacks would likely be in the one mile range and complaints would be minimal. But a mile setback doesn’t meet the wind developers’ needs, so Ontario sacrifices its citizens for corporate profit.
And that isn’t all. Both the turbines and projects used in the Pedersen studies are a fraction of the size of those in Ontario. There’s evidence that the larger turbines are not only louder, but their spectrum shifts towards lower frequencies, plus the turbulence between multiple turbines increases the noise too. Below is the chart with all of the turbines in Pedersen’s studies; to compare Sweden’s circumstances with Ontario’s is just not appropriate.
Finally, how much energy is produced by Sweden’s turbines compared with Ontario’s? Ontario’s average has been slightly above 26%, Sweden’s is about 19%.
No wonder Sweden’s complaint rates are so low: their homes are further away due to the 8 m/s calibration point, the smaller projects and turbines, and the low utilization. A real problem is that reporters, judges and politicians listen to people like King and the Sierra Club without understanding all the wrinkles that make what they say totally unrelated to the reality of people who live in the shadow of wind turbines. I suspect that King and the Sierra Club don’t understand these wrinkles either, and I have to wonder if some of that lack of understanding is intentional.