The wind energy industry has a long list of “studies” (i.e. Chapman’s 17) that they claim “proves” that wind turbines present no health issues for nearby residents. One of my strongest criticisms of all of these studies is that nowhere in them has anyone ever gone to a victim’s home and actually measured what was going on in there. There’s good reasons why they don’t.
Three families living within the Shirley project in Wisconsin have abandoned their homes and gave evidence to that effect (along with 50 other affidavits) in front of the Wisconsin PSC. While the industry of course will try to discredit their experiences with all the usual innuendos the stories have the ring of truth and the PSC, to their credit, recognized this. The complaints included the following details:
- Wind direction didn’t matter
- Every above-grade room was affected
- Worse indoor than out
- No or little audible sound
- The basement gave some relief
- Some people were seriously affected, others not at all
- No in-between – it was either tolerable or not
- Staying away (and eventually moving away) did fix the symptoms
The specificity and details are convincing to anyone willing to listen. A acoustician with close ties to the industry (Hessler) proposed going into the homes and doing some testing, concentrating on infrasound. The homeowners balked, fearing (rightfully, in my opinion) that Hessler would predictably find nothing. Finally it was agreed that 4 acousticians with differing perspectives would participate. The PSC and a pro-green-energy organization named Clean Wisconsin ponied up some money and early in December 2012 everyone converged in Wisconsin for 3 days of measurements. Although the acousticians have represented both proponents and opponents (in differing proportions), they are all pro-wind – assuming the siting was away from neighbors.
One of the things the group wanted was to verify how much of the noise was actually being created by the turbines, vs normal sources of infrasound. This would have required the cooperation of Duke Energy, who would have had to turn the turbines off for “short intervals”. Almost needless to say, Duke declined to cooperate, citing lost revenues. I don’t know what “short intervals” translates to, but if each turbine generates at best about $200 worth of electricity per hour, the total lost revenues probably comes to well short of, say, $5000. I can pretty much guarantee that 3 days of 4 acousticians (and a mountain of equipment) cost a great deal more than that. Duke had $14B+ in revenues last year. Using “lost revenues” as an excuse isn’t credible. I think we can all guess what is credible – Duke knows what their turbines are doing to the health of the neighbors and wants to deny and delay as long as possible. Morality and decency be damned.
The resulting report was 52 pages long, with an 8-page body that was jointly authored and 4 individually-authored appendices. The body is reasonably readable while the appendices get pretty technical. The money quote, from the body on page 7, is: “The four investigating firms are of the opinion that enough evidence and hypotheses have been given herein to classify LFN and infrasound as a serious issue, possibly affecting the future of the industry. It should be addressed beyond the present practice of showing that wind turbine levels are magnitudes below the threshold of hearing at low frequencies.” When 4 pro-wind professionals state that infrasound is a serious issue, “possibly affecting the future of the industry” I’d hope that previously passive governments would take notice.
I won’t (thankfully!) go through all the details. There are, however, several interesting tidbits.
- Rob Rand was the only acoustician known to suffer from seasickness, and he was also the only acoustician to be personally affected by the infrasound. There is likely some common mechanism to both, although it is too early to do more than speculate.
- Previous assertions (and that’s all they were) about the absence of infrasound (i.e. Leventhall and Jakobsen) that were embraced by the wind industry have been shown to be untrue.
- The frequencies of interest were on the same scale as the “blade pass frequency”, or how often the blade passes the tower, plus their harmonics.
- The “noise” may be better thought of as a pressure wave. The wave could be created as the blade passes the tower, or perhaps as the blade flexes back on the downstroke as it encounters slower wind (google “wind shear”).
- As turbines get larger they tend to have several characteristics that make them more problematical for the neighbors:
- Their additional height catches better and more consistent wind. This may be good for capacity factors but extends the periods of noise, especially at night.
- Their additional size and power creates more noise to begin with.
- Their additional size shifts the noise created to lower frequencies.
- Their longer blades flex more (due to both their length and to the greater wind shear), potentially creating larger pressure waves.
- They rotate slower, getting closer to the peak frequencies of something called “nauseogenicity”.
Nauseogenicity is a new term to me and probably to you too. I have visions of nerdy teenagers throwing the insult that someone is the epitome of nauseogenicity. It stems from early Navy research that discovered that certain frequencies induced motion sickness in pilots. Rand created a chart that showed how the blade passing frequencies of larger turbines have converged on nauseogenicity’s peak frequencies.
Like all studies there are aspects to this one that you could quibble with. But let there be no mistake – this study is far and away the most rigorous one undertaken to date, and the unanimous opinion of the participants is that infrasound represents a very serious (even industry-threatening) problem. Below are a number of links to other commentaries.
Green Bay Press Gazette, back in November. Read the comments for some truly uncaring and ignorant viewpoints.
Green Bay Press Gazette, in December.
Update: Acoustic Ecology Institute, nice review of the study
Update: Wind Wise Radio, Rob Rand Interview, 69:50 in (the first half is also very interesting and very germane)
Update: The wind industry has been spinning this report, claiming that it found no evidence of health issues. This seems a strange critique, as these are acousticians not medical researchers, and have no business opining on health issues, and in fact didn’t say anything about health. Rob Rand, in the Wind Wise Radio interview above, explains very well his approach to the health issue.