Ever since Duke Energy proposed building 112 utility-scale wind turbines in southern Benzie and northern Manistee Counties, opponents of the idea have sent dozens of letters to the Benzie County Record Patriot warning of the harm the project would cause.
The paper has also published several guest editorials opposing the project.
Most opponents concentrated on one of three issues: the effect of such a large development on the region’s viewscape, property values, and tourism; public health; or local bird and bat populations.
|Wind farm planners can use computers to determine where to site turbines to avoid throwing irritating, flickering shadows across highways or occupied buildings.|
Reporting by the Great Lakes Bulletin News Service, however, indicates that most concerns the approximately 60 letters raised are not backed by the most thorough current research—particularly, when available, peer-reviewed studies.
Trouble for Tourism, Property Values?
Of the Record-Patriot letters published since November 2010 opposing the project, the greatest number expressed fears about turbines’ effects on local tourism and property values. About 20 focuses exclusively on tourism and or property values; roughly 15 others alluded to those fears while raising other objections.
The Great Lakes Bulletin News Service, however, interviewed chamber of commerce or tourism officials in three scenic, tourist-friendly communities with large wind farms. Each official said turbines had proved to be either neutral to or a modest “plus” for tourism.
The story also unearthed four news reports, from Palm Springs, Calif. to Cape Cod, Mass., of wind farms that are or will soon become paid tourist attractions. It also found two academic studies, one rigorously constructed, revealing strong outstate tourist interest in visiting ocean beaches or paying for boat rides to view offshore turbines.
GLBNS also turned up dozens of other, non-academic studies and reports confirming this trend, and only four that said turbines harm tourism. Those four studies, of tourists in the United Kingdom, found that, on average, 11 percent of respondents said they would not return to a locale if there were wind turbines, according to a 2006 report by the UK’s Small Business Council.
“A large number of the visitors surveyed [65.5 percent on average],” the Council added, “did not feel the wind turbines would make a difference to whether they returned or not to the destination.”
Worries about wind farms lowering property values also seem misplaced.
The most well known study, peer-reviewed work by Lawrence Berkley National Laboratory, found that homes closest to turbines sometimes increased in value after they were built.
The 2009 study examined sales of 7,500 homes situated from 800 feet to 10 miles from 24 American wind farms and found that only the prices of those within one mile were affected. For homes within 3,000 feet of a turbine, values exceeded original levels after temporary decreases when the farms were first announced.
While Lawrence Berkeley doesn’t claim that turbines increase nearby homes’ values, it maintains that “no evidence is found that home prices surrounding wind facilities are consistently, measurably, and significantly affected by either the view of wind facilities or the distance of the home to those facilities.”
In 2003, a federally financed study covering 25,000 sales within five miles of nine wind farms in seven states reached a similar conclusion.
The 2009 study was challenged by Missouri realtor Albert R. Wilson on grounds that its analysis methods don’t meet the standards of the International Association for Assessing Officers, a real-estate appraisal non-profit. Mr. Wilson, who has written extensively about environmentally damaged real-estate value, did not state his own view on the question, but claimed that Lawrence Berkeley’s report “should not be given serious consideration for any policy purpose.”
Lawrence Berkeley’s study, however, is “believed to be the most comprehensive to date on the subject,” by the Michigan Public Service Commission.
Many opponents also worried about turbines’ health effects. Though few of these 20-plus Record-Patriot letter writers cited specific maladies, national anti-wind advocates claim that utility-scale wind power causes a slew of diseases and disorders, from sleep disturbance and deprivation to accelerated heart rhythm.
In an April editorial the Arcadia Wind Study Group, a citizens group in Manistee County opposing local, utility-scale wind turbine development, placed “health issues from noise, vibration, and light flicker” first on its list of objections. Many Record-Patriot letters echoed these concerns.
Many sound experts do view turbine noise as a possible problem, but they say that it should be kept in perspective.
One expert, Jim Cummings, is executive director of the Acoustic Ecology Institute, a Santa Fe non-profit that provides news, research, and policy advocacy about sound and listening. In an editorial, Mr. Cummings summarized current wind turbine noise research.
“Wind farm noise issues are subtler than the anti-wind groups may fear,” he said, “but much more real than the industry would like to believe.”
In 2010 Mr. Cummings spoke as a part of the New England Wind Energy Education Project (NEWEEP), a conference and series of webinars conducted by the New England Wind Forum and funded by the U.S. Department of Energy’s Wind Powering America Initiative.
He analyzed three surveys of about 1,800 people living near turbines in Sweden and the Netherlands and found that noise complaints “are the exception rather than the rule.” On average, Mr. Cummings said, less than 10 percent of those surveyed reported annoyance.
The studies found that annoyance is more common in rural areas, and turbines cause twice the annoyance of noise from road and aircraft traffic.
But “annoyance doesn’t imply a constant plague,” Mr. Cummings said. Only a quarter of the 10 percent of people annoyed by turbines were bothered daily. Half were disturbed only “once or twice a week,” and half were disturbed only outside of their homes.
He also found that annoyance correlated strongly with negative attitudes towards wind turbines.
The vibrations AWSG warns against are sounds so low in pitch that humans cannot hear them—“infrasound.” Like many mechanical and natural phenomena, utility-scale wind turbines produce infrasound, which, by definition, does not pose a nuisance because, except in extraordinary circumstances, humans cannot hear it.
Yet opponents claim that infrasound triggers “vibroacoustic disease” and “wind turbine syndrome,” disorders characterized by irregular heart rhythm, nausea, dizziness, difficulty concentrating, and other symptoms. They often point to a book by New York pediatrician Nina Pierpont, Wind Turbine Syndrome: A Report on a Natural Experiment.
Pierpont and other wind-disease researchers’ work, however, is inconclusive, according to scientists who investigated the claim. Wind Turbine Sound and Health Effects, a 2009 report from a panel of doctors, professors, and acoustic engineers assembled by the American and Canadian Wind Energy Associations, found that studies identifying these problems failed to use basic scientific methods such as control groups and peer review.
The panel also pointed out that pediatrician Pierpont’s work was based on a misunderstanding of how the human body is affected by infrasound. Because of such flaws, the group saw no need to further investigate such studies. Since first reporting on Ms. Pierpont’s claims, the Great Lakes Bulletin News Service has been unable to find follow-up studies that look more closely at them, although they are at least six years old.
Meanwhile, according to a Japanese news report, the Japanese Ministry of the Environment is conducting its own large-scale study on the health effects of wind turbine infrasound; its results will be released next year.
Flicker: More than a Nuisance?
AWSG also warns against “flicker,” a strobe-like lighting effect caused by turbine blades throwing shadows across the landscape in bright sunlight. Like turbine noise, flicker stands accused of being a nuisance and harming health.
Some turbine opponents claim that this unusual lighting effect can cause epileptic seizures. But several speakers at Understanding the Current Science, Regulation, and Mitigation of Shadow Flicker, another NEWEEP webinar, said they could find no clinical research and only a few anecdotes supporting that claim.
The U.S. National Library of Medicine’s PubMed online article database lists two studies concluding that turbines may cause seizures if they flicker more than three times per second. The Epilepsy Foundation sets the bar higher—light flashing five to 30 times per second. Utility-scale wind turbines, however, flicker no more than once per second, according to NEWEEP speaker Thomas Priestly, senior environmental planner at the multi-national construction company CH2MHill.
Record Patriot letters and statements on AWSG’s Web site claim flicker is a significant nuisance. Researchers agree that flicker can be a problem, but say it occurs infrequently.
NEWEEP speaker Matthew Allen, a 20-year, veteran visual impact assessor at Saratoga Associates, an New York architecture firm, reported that turbine flicker rarely occurs for more than 30 hours a year at any location. Mr. Allen said flicker’s common pattern is 30 minutes a day for two isolated, weeklong periods each year. He added that this is usually a worst-case scenario, because overcast or cloudy skies, trees, buildings, or other visual obstacles often block flicker. At one residence he studied, such factors cut flicker hours per year from a possible 33 to an observed 9.5.
Wondering about Winged Wildlife
The third-most common objection from letter writers concerned turbines’ harm to wildlife. About 15 Record Patriot letters warned against bird and bat collisions with turbine blades.
According to a 2005 report to Congress by the U.S. Government Accountability Office, however, “it does not appear that wind power is responsible for a significant number of bird deaths.”
Bat deaths related to wind turbines may be a different matter. They have at times reached significant numbers in several areas.
In its review of 30 studies conducted in the West, Pacific Northwest, Midwest, and Northeast, GAO found that only California and Appalachia had worrisome numbers of bird or bat fatalities.
In Northern California, one study estimated, turbines collectively killed 1,000 birds of prey annually. Those deaths were mostly at Altamont Pass, which has the largest concentration of wind turbines in the world. In Appalachia, which stretches from Pennsylvania to Alabama along the Appalachian Mountains, bat deaths were as high as 38 per turbine, per year.
These figures, however, are highly unusual. Outside of California the study found that wind turbines killed seven or fewer birds per turbine, per year.
Altamont Pass, where four of the five Northern California studies considered by GAO were conducted, is uniquely deadly among wind farms. It’s the world’s biggest, with 5,400 relatively small turbines sited along ridge tops and canyon edges where a large population of predatory birds often fly.
The turbines, built in the 1980s, have outdated structural characteristics dangerous to birds, such as guy wires and rapidly spinning, low-mounted blades. As predatory birds swoop down on prey, which are abundant at the base of turbines, according to the report, they frequently collide with the blades. The Altamont facility is now replacing the old turbines with fewer, larger, slower-rotating ones.
In Appalachia, however, “scientists do not have a complete understanding regarding why these [bat] collisions occur,” the report said, and so does not speculate on regional irregularities.
It did, however, report that there were fewer than four bat deaths per turbine per year outside of Appalachia.
Andrew Willens is a senior at Oberlin College and is interning for the Great Lakes Bulletin News Service this summer. You can reach him at firstname.lastname@example.org.