Following up on concerns expressed by locals near the Mars Hill wind farm, and preliminary studies done by a local doctor, the Maine Medical Association overwhelmingly approved a formal resolution that stresses “a need for modification of the State’s regulatory process for siting wind energy developments,” in order to reduce controversy and incorporate the latest evidence-based research results. The statement urges the Department of Environmental Protection and Land Use Regulation Commission to refine their procedures to reflect potential health effects, and to concertedly explore these effects, and calls on the MMA and doctors to work with regulatory agencies to provide what scientific information is available (scroll down at link above to read the final resolution wording). Two weeks earlier, the MMA’s Public Health Committee had rejected the proposed resolution, which many members felt was worded more strongly than current evidence would support; the resolution was slightly re-worked, and met with approval at the MMA’s annual session.  One of the resolution’s sponsors, Dr. Michael Nissenbaum, MD, is in the midst of completing a study of the residents both near the Mars Hill wind farm, and those further away, in an attempt to assess any significant differences.  The first part of his study (centered on interviews with wind farm neighbors) is available now, with the second part (similar interviews with residents out of earshot) still underway. A two-part radio interview with Nissembaum is available here.  A two-part local news feature on the Mars Hill controversy is available here.

A feature article in the fall issue of The Nature Conservancy’s magazine takes a close look at the rapid expansion of the wind industry in America’s prairie heartland.  The rolling hills of Kansas are a prime wind energy corridor, and TNC is concerned that the remnants of tallgrass prairie habitats could be irrevocably harmed if new wind farm development is not done carefully.  Rob Manes, TNC’s Director of Conservation for Kansas, sits on the Fish and Wildlife Service advisory committee that is developing wind farm siting guidelines, where he has proposed that key habitat be identified in advance, so that wind companies can plan around it.  Such landscape-scale analysis is already being done by some wind companies, and Manes urged the committee to recommend that the practice become standard procedure.  Manes imagines an ever-expanding regional database that would not only would provide maps of important environmental data, such as critical habitat for endangered species, but also would designate wind-friendly areas where turbines and wildlife are less likely to be in conflict.  (This idea is closely related to Marine Spatial Planning, as addressed in this recent AEInews post.)

From the TNC article: Manes is certain that a national set of detailed maps overlapping wind and wildlife resources is crucial to “doing wind power right.” That is because the Conservancy and its partners have already implemented a system of maps in Kansas. And local developers have responded enthusiastically. Horizon Wind Energy even worked with the Conservancy and the Ranchland Trust of Kansas to set aside protected lands to offset the footprint of one of its wind-farm developments.  “Our contacts in the wind industry said, Show us where we can develop our projects — so we did,” Manes says. The map shows the state’s native prairies, prairie chicken habitat, wildlife refuges and nature preserves, as well as where the best wind resources are. Now, when a wind developer wants to build in Kansas, the company knows which sites are likely to raise the ire of conservationists — and which areas aren’t.

The Conservancy has created similar maps in a handful of other states, including Colorado, Montana and Oklahoma. And in mid-2009, the Conservancy was awarded a contract to create a wind and wildlife resource map for the entire country. The map initiative is funded by the American Wind and Wildlife Institute, a coalition of wind-industry and conservation organizations with the aim of reducing conflicts between wind development and wildlife.

UPDATE: In the UK, the Royal Society for the Preservation of Birds, along with Scottish Natural Heritage, has initiated a similar project, centered on the production of a Bird Sensitivity Map for use in planning wind farms in Scotland. See this link for more information on the program, and click here to download the BSPB Bird Sensitivity Map Report.  Scottish Heritage previously released “Strategic Locational Guidance” for onshore wind farms.

While the province of Ontario appears to be onto something promising with its new Green Energy Act (see recent AEInews post), local wind skeptics point out that in recent years, the province has taken wind developers’ environmental assessments at face value.  Citizens can request that the province conduct a full-scale independent assessment, and indeed, such requests have been put forward 31 times since 2006.  In every instance to date, however, the request has been denied (nine are currently outstanding).  Provincial authorities assure that the required private assessments include taking into account citizen concerns, and often involve mitigation, as part of “a lot of back and forth” between the companies and provincial regulators.  Regarding noise issues (AEI’s primary concern), it would seem prudent to do some “ground-truthing” of industry sound propagation models: if there are instances in which neighbors are being affected by unexpectedly high noise levels, then future assessments should be sure to not use the same models that failed earlier.  This is but one example of the value that even a few independent assessments could offer as the province moves forward with its ambitious plans to abandon coal-generated power.

A great short piece in Canada’s esteemed Maclean’s magazine from early August highlights the aggressive push being made by provincial minister of energy to open up the province for wind power.  George Smitherman, the self-styled “Mr. Wind,” may be on to something, because his initiatives are stirring up both anti-wind activists concerned about noise and health effects AND the industry itself, aghast at new setback requirements for large wind farms.

A combination of requiring utilities to enter into long-term, premium price contracts with wind farms and a massive upgrade to the distribution grid has spurred plans for 103 new “shovel-ready” windfarms in the Province, especially along its extensive Great Lakes shorelines.  This has locals worried, after hearing tales of woe from wind farm neighbors elsewhere.  Dr. Robert McMurtry, a former dean of medicine at the University of Western Ontario, says that  “When I first read about the side effects I thought that they didn’t sound very convincing. But then I did my homework, and I became alarmed.”  Based on surveys he has done, and others in Europe, McMurtry estimates that 25 per cent of people living within 2.5 km of turbines experience disruptions in their daily lives, especially sleep disturbances, which often balloon into other health problems. He thinks that there are enough problems, in wind farms worldwide, to justify a serious epidemiological look at the industry. “You can assume that all these people are liars,” says McMurtry. “But many of these folks will tell you that they welcome wind turbines. They just want someone to turn them off at night, or move them further back.”

New provincial set-back standards issued in June may well be just what this doctor ordered. While not going all the way to 2.5km (about 1.5mi), the new standards call for increasingly large setbacks for larger windfarms, peaking at 1.5km (just under a mile) for wind farms of over 26 turbines; smaller wind farms can be 550m away, loud small ones 950m away.  The Canadian Wind Energy Association claims that these new rules will require changes in 96 of the projects, with 48% of their turbines out of compliance; 79 of the projects are now either “non-viable” or require “back to the drawing board” redesign.

Smitherman is not phased by either side’s reactions.  “I totally understand that there aren’t many people out there looking for more electricity infrastructure in their backyards,” he says. And if somebody has to go back to the drawing board and redesign some projects, “I apologize that it will be inconvenient in some circumstances. But bigger setbacks are part of the Green Act.” But he’s unapologetic about the larger goal, one that would be truly revolutionary: to eliminate coal-fired electricity by 2014—only five years away.

An Ontario group that compiles reports of troubles with wind farms has claimed that wind power companies have spent $1.75 million to buy six homes in Dufferin County.  According to the report, these six families had found their homes unlivable after wind farms began operations, and all were required to sign gag orders as part of their buy-outs. Given the gag orders, hard information on the distances from each home to operating turbines is not fully available, but from limited personal communication with folks in the area, it appears that the homes ranged from 700m to 2.5km from the turbines (just under a half mile to just over 1.5 miles).

UPDATE 11/09: According to Canadian Hydro Developers, only two of the homes were purchased due to noise issues; the others, the company says, were purchased during construction for company personnel, and will be resold.  More on this in a recent article here.

As AEI has tracked noise complaints around wind farms on land, which seem fairly common between a half mile and mile (and in some cases up to a mile and half or so), I’ve held on to the idea that offshore will be the better way to go.  Offshore wind developers have been mostly aiming for siting turbines far enough offshore to minimize visual impacts (2 or more miles), which I had assumed would also make them inaudible from shore.  But recent reports are throwing some doubts on that hopeful thought.  We need to hear more from other locations, but a wind farm that began operating on Wolfe Island, Ontario, this summer has surprised local observers with its long-range sound transmission.

Wolfe Island Wind Farm

Wolfe Island is at the eastern end of Lake Ontario, at the mouth of the St. Lawrence Seaway.  Even ship operators have noticed turbine noise at 2-3 miles distant (and ships are not exactly a quiet place to listen from), and locals across the channel in Cape Vincent, NY have also been hearing the wind farm readily at 2-3 miles, and, in some atmospheric conditions, as far away as 7 miles!  Yikes….   The reasons for the easy long-range sound transmission are not yet known, though sound does travel well across water, so that may be a key feature.  If so, it ups the ante on offshore wind farms, at least when prevailing winds are toward shore.  (Though we must note that this is not along the coast, but rather at the end of a huge lake which fosters strong prevailing winds.) This one is not yet a clear red flag, but it bears watching….

And, on a brighter note, the health of Wolfe Island residents is being charted by Queen’s University researchers, in the first research study to assess health before and after wind farm operations begin in a community.  This is an important next step in clarifying whether the health effects that have previously been reported are widespread, or rare.

With one of the nation’s “poster child” noisy wind farms in Mars Hill and a popular former governor advocating (and financing) more use of wind power, the State of Maine continues to be at the forefront of the debate over how much credence to give to neighbors’ reports and concerns about wind turbines close to their homes.  Seventeen neighbors of the Mars Hill wind farm, who live from under 2000 feet out to 3600 feet from active turbines, have filed suit against the wind farm developer, asking for compensation for loss of property values, nuisance and emotional distress, and upgrades to the turbines to make them quieter (download the full complaint).

The Todd Residence in Mars Hill. Photo by Anne Ravana.

The state gave the Mars Hill farm a variance to the state noise ordinance, allowing it to be 5dB louder than normally permitted; recordings made by a state-funded acoustics firm indicated that not all locations were fully in compliance, yet the state signed off on the results as being good enough.  The state also hired an acoustics consultant to peer-review the monitoring study, and in his report, this consultant expressed several concerns with the results, saying that “wind turbine noise needs more investigation!” Read the rest of this entry »

The North Dakota Public Service Commission declined to intervene in a last-minute request from a Luverne couple who wanted a neighboring wind farm moved from near their property line.  The Jim and Mary Anne Miller build dog sleds and keep 21 huskies for testing them, and were concerned that the 80 turbines planned in an area extending out to a half mile from their home would be disruptive to both the dogs and them. “I think it’s ridiculous that they would force this noise onto us, and we’re supposed to be happy about it,” Mary Ann Miller said in an AP story. The quiet of the rural area “is one of the big assets that we have here,” she said. “We don’t live next to Kmart or Wal-Mart.”  The PSC agreed only to ask the wind farm developer, NextEra Energy Corporation, if it would be practical to move the project to a half to three-quarters of a mile from the Millers, as they had hoped, a move of roughly a quarter mile.  However, construction of four of the turbine foundations has already begun, a NextEra spokesman said determining the placements was a “highly technical exercise” that could not easily be changed. “We think that the array that we’ve laid out is very sound for a number of reasons,” Stengel said. “Once we do that, we don’t think there is any need to move those turbines.”  The project was approved in June. UPDATE: This news report from the week before the hearing says that only the 4 turbines under construction (the closest of which was 1400 feet from a home) were under dispute and being asked to be moved, and that the company apparently began construction with those very four.  “I’m just incredibly frustrated,” said Merrie Helm, one of the neighbors asking for the turbines to be moved to a half mile from homes. “It’s like the small person in North Dakota just doesn’t matter. That’s how it feels.”

This case is one of the first that has revolved around what appears to be a common threshold for noise issues with wind farms, the half mile to mile range.  Though setbacks of a mile or more may still be warranted if the goal is to avoid noise problems altogether, very few serious noise complaints have arisen from wind farms that are three-quarters of a mile or more from homes.  Thus the Millers request, while coming too late for serious consideration, was very reasonable.  A recent report from the UK highlights another perspective on this half-mile issue: the Westmills Wind Farm consists of four turbines, all within a half mile of the village of Watchfield.  However, the project brought 2400 locals into a cooperative which owns 100% of the farm.  This is an example of a growing trend in the UK, by which communities buy into wind farm projects.  In these cases, it may well be that occasional noise issues are more easily accepted, in contrast to projects in which the noise is foisted upon unwilling neighbors.  An important note is that (as usual), news reports on both of these cases neglected to clarify whether the homes a half mile away were upwind or downwind of the wind farm sites, which can make a huge difference as to whether noise issues are likely to crop up.

A recent article in the UK newspaper The Independent has triggered an avalanche of commentary in the press and blogosphere about the possible health effects of living near wind farms; more is sure to come when Nina Pierpont’s Wind Turbine Syndrome book is finally published this fall. In the book, Pierpont posits a set of symptoms that can crop up in people exposed to wind turbine noise; she suspects that low frequency noise is the key factor, and that people with vestibular system imbalances may be especially prone to problems. UPDATE: The wind industry in the UK responded vehemently to the article, which was reprinted in several cities.

At its root, most of the hubbub centers around whether Dr. Pierpont’s research qualifies as science.  The fact that she’s publishing a book instead of journal articles is the first complaint, and relatively easy to understand from a scientific perspective.  But less valid are critiques that claim she used too small a number of people, or did not use “controls”; these complaints are based on a misunderstanding (or conscious misrepresentation) of her work. Much of the criticism is spurred by the perception that she is claiming that the health effects she cites are common, or are likely to occur near any and all wind farms.  As widely noted, wind farms are up and running around the world with little evidence of dire health effects.  However, just as anti-wind activists are clearly putting too much weight on her very preliminary research, so too are wind advocates being too quick to discount Pierpont’s study as hogwash.  More broadly, there is a risk that doubts about the validity of  a formal new “Wind Turbine Syndrome” or other low-frequency effects will distract both the public and policy-makers from the more concrete question of whether current wind farm setbacks adequately protect neighbors from sleeplessness, stress, and simpler, well-known effects of disturbances caused by audible noise.  I’ve been bouncing around the web in recent days, adding what I hope are thoughtful comments to newspaper and blog stories on the issue, and wanted to share some of my commentary here with you all as well: Read the rest of this entry »

The Minnesota Public Utilities Commission has initiated a formal investigation of wind turbine setback requirements, after numerous complaints about noise.  Minnesota Public Radio has a long piece on the process (both audio and a transcript), and a local regulatory advocate points us to the right documents on the PUC website for more information.

A recently-released report by Dr. Christopher Hanning, a UK MD whose specialty is sleep disorders, takes a comprehensive look at factors affecting sleep disturbance caused by nearby wind farms, and is highly recommended reading for anyone working to develop regulations at the local or state level.  Hanning’s primary point is that external noise need not WAKE a sleeper to cause problems, and the repeated “arousals” can break the most restful periods of sleep.  He notes that “The sleep, because it is broken, is unrefreshing, resulting in sleepiness, fatigue, headaches and poor memory and concentration.”  These are precisely the symptoms often reported by people living near wind farms. He stresses that arousals are also associated with “physiological changes, an increase in heart rate and blood pressure, which are thought to be responsible for the increase in cardiovascular risk. Arousals occur naturally during sleep and increase with age (Boselli 1998) which may make the elderly more vulnerable to wind turbine noise. Arousals may be caused by sound events as low as 32 dBA and awakenings with events of 42dBA (Muzet and Miedema 2005), well within the measured noise levels of current wind farms” and the levels permitted by most jurisdictions.

The report also summarizes other studies suggesting that night-time noise levels are often higher than sound models predict, as well as one that suggests that wind farms cause high levels of annoyance at lower sound levels than other common noise sources.  He concludes that “While it may be possible to produce a reasonable acoustically based theoretical approach to calculating set back distances (Kamperman and James 2008b), it makes more sense to rely on recommendations from observations of the effects on real people at established wind farms.”

Download the full report here.

Thanks to Lynda Barry at National Wind Watch for the heads up.

In a startling and far-reaching decision, the Wisconsin Supreme Court has ruled that counties cannot issue “blanket” standards for wind farm development, but must assess each project on a case-by-case basis.  The ruling invalidated one of the nation’s most precautionary local ordinances, passed in 2008 by Calumet County, but also undermines the logic behind any uniform standard for wind farm regulation.  The Calumet County ordinance adopted an “audible sound” standard as well as an 1800-foot setback (though the Supreme Court ruling would apparently not allow either approach).  The audible noise standard would, in most cases, have been the more stringent limit, as it allowed only a maximum of 5dB above the background ambient sound level at the quietest time of day or night; it is likely that night-time ambient noise is in the range of 25-35dB.  This sort of standard is designed to assure that the wind farms do not appreciably change the character of the local soundscape, and will not become the loudest sound at any neighboring houses. In practice, the audible noise standard used would likely create difficulties in siting turbines closer than about a mile from most homes.  By contrast, industry proponents generally favor a 1000 or 1500-foot setback, or a noise limit of 45-55dB. (Note: half-mile setbacks are becoming more common, and recently an Australian shire joined other localities around the world in adopting a 2km setback, which equates to just over a mile.) At the time the ordinance was issued, industry spokesman responded that it would trigger the “war to end all wars” over wind development regulations; the recent ruling comes as the Wisconsin state legislature is working to adopt state-wide standards for wind development.  For more info, you can read several articles covering the recent ruling, this article covering the adoption of the ordinance, or see the ordinance itself.

The US Fish and Wildlife Service has drawn a clear line in Wyoming, stating that designated Core Habitat for the Sage Grouse must remain free of wind turbines.  Even turbines built in order to conduct further research on effects on sage grouse would “negate the usefulness of the core area concept,” according to a response from the FWS to inquiries from the Wyoming Game and Fish Department.  In addition, mitigation aimed at minimizing the impacts of wind farms is considered inappropriate in these core habitat areas.  The implication is that any research efforts should take place in less critical habitat.  Aaron Clark, an adviser on energy infrastructure to Wyoming Governor Dave Freudenthal, said the governor’s office supports the Fish and Wildlife Service’s hard line on wind farms in core areas. “We don’t want to close the door on everything for ever,” Clark said. “If somebody can bring in some really good science that shows that wind turbines don’t have an adverse effect on sage grouse, obviously then our position needs to change. But everything we’ve seen so far is pointing the exact opposite way.” For more info, see this AP story, read a Press Release from the Wyoming Game and Fish Department, or read the letter from the FWS to the State GFD.

UPDATE 8/13/09: Horizon Wind has indefinitely suspended its planning for one of the two wind farms planned for the sage grouse core habitat, though a spokesman affirms that “the project is not dead.”  This New York Times article provides a clear recap of Wyoming’s initial plan to allow two wind farms in the core habitat, in order to study their impacts as several other wind farms await approval. The state, which is working hard to avoid having the FWS list the grouse as endangered, had requested guidance on their plan, and received a rebuke from FWS.

After a bit of a lull, I’ve spent much of the past couple days catching up on the folder full of research published in recent months, and summarizing key papers on the main Acoustic Ecology site.  Among the studies worthy of attention are:

• The first direct test of harbor porpoise sensitivity to seismic survey airguns confirms many observations from the field that this species is especially sensitive to noise; both temporary hearing loss and avoidance of sound occur at relatively low noise levels
• Orcas and dolphins seen to reduce foraging in the presence of boat noise
• Wind turbines don’t seem to replace most small wintering farm birds, but oil development noise can reduce forest bird abundance
• Right whales summer habitat is loud most of the time, suggesting a pressing need to identify their breeding grounds and assure they can hear each other there
• Two great overviews of fish hearing

See these and more at the AEI lay summaries of new research page.

For the first time, researchers have designed and initiated a broad-scale study that will provide enough data to begin to answer one of the key questions looming over wind energy development: do turbines close to residences create negative health effects?  The researchers sent health surveys to 1000 residents near a proposed wind farm; between 150 and 200 returned the survey, and received follow-up questionnaires as the wind farm completed construction.  Later rounds of study will seek to discover whether any reported changes in health are related to distance from the wind turbines, as well as correlating reported problems to individuals’ initial feelings about the new wind farm.   Read the rest of this entry »

After my participation on a Canadian government expert group looking at offshore oil and gas noise, I headed west to Banff for my second appearance as a plenary speaker at the Alberta oil and gas industry’s biannual Spring Noise Conference. Here, participants are largely agency staff and noise control contractors, with a few oil and gas companies participating as well. Alberta has a vibrant oil and gas industry (read: most important economic driver for the Province), and while the landscape is heavily tapped by traditional oil and natural gas drilling, coalbed methane development, surface coal mining, and, infamously, oil sands development, Alberta’s noise regulations are among the most stringent in the world: impact on neighbors cannot exceed 5dB above the local ambient noise conditions.  This year’s conference (and the very informative pre-conference workshop I attended) expanded from its roots in oil and gas development, to include wind farms.

Read the rest of this entry »

The revised draft of wind energy wildlife impact guidelines released by a US Fish and Wildlife Service Federal Advisory Committee was released in March, and like the first version, contains not a single occurrence of the words “noise” or “acoustic.” The Committee is directed to “recommend effective measures to avoid or minimize impacts to wildlife and their habitats related to land-based wind energy facilities.” How they can provide provide this guidance without considering acoustic impacts is simply unimaginable.  Modern wind turbines are hundreds of feet tall, and create significant sound; even the minimal setbacks for human residences are 1000 feet, with many cases of bothersome noise (especially at night) at a half mile or more.  Wildlife impacts of wind farms are sure to include increased ambient background noise over a fairly large area (half mile to a mile in diameter), which can make it more difficult for predators such as owls and coyotes to find their small prey, and likewise force prey animals to be more vigilant against attack, which has clear energy costs for the animals.  In addition, low-frequency noise radiated into the ground could affect burrowing animals.  Especially in “islands” of woods along ridgelines surrounded by farm land, this acoustic degradation could displace animals from key habitat; even in larger woodlands, steep terrain along ridgelines often contains a different mix of trees and thus habitat that is locally important.  As AEI noted in comments submitted to committee members in February, “In at least some situations/locations, acoustic impacts could be a primary or substantial contributing factor in displacement from habitat, as well as triggering stress that may have synergistic relationships with other impacts.”  Such considerations are basic requirements for effective analysis of impacts on wildlife.  The Committee briefly considered noise impacts, but concluded that no data (specifically involving turbine noise) was available with which to assess the possible effects.  As with ocean noise, though, this lack of specific data does not preclude assessing possible or likely impacts, using studies of other noise sources or even other species than those present at a given project area; NOAA and the Navy routinely take this approach to assessing the impacts of various ocean noise sources.  There is plenty of research on the noise impacts of oil and gas installations, road noise, and aircraft noise on many families of wildlife (birds, rodents, large mammals, etc.).  The National Park Service Natural Sounds office and bioacoustics researchers at universities across the country are good sources of information that this Federal Advisory Committee surely needs to consult before moving forward with guidelines for assessing the impacts of wind farms on wildlife.  These guidelines will shape wildlife impact analyses for years to come, and need to be done right.  

For more on the FWS wind advisory committee, see:
http://www.windaction.org/articles/21154
Industrial Wind Action Group letter to Sec. of Interior Salazar, May 2009

http://www.fws.gov/habitatconservation/windpower/wind_turbine_advisory_committee.html
Advisory Committee website 

Debate continues to swirl around wind farm development across the US, as local communities struggle to find the right balance between green energy and minimizing impacts on wind farm neighbors.  At the crux of the issue is how close to homes turbines should be built.  The wind energy continues to push for setbacks as small as 1000 feet, while local residents report significant noise impacts up to a half mile or mile.  In Wisconsin, where five wind farm proposals have been derailed since 2007 by local setback ordinances of 1800 feet to a mile, which the industry deemed too severe, a push is on in the state legislature to transfer all decision-making power to state authorities, stripping localities of regulatory authority.  In Maine, two physicians have urged the state to take note of clear health effects caused by audible noise from the Mars Hill windfarm: Read the rest of this entry »

Increasingly, local regulators are settling on a half-mile setback for wind turbines, despite many reports of noise issues beyond that distance.  At the Willow Creek Wind Farm in Morrow County, Oregon, local residents raised concerns in November when the developer’s noise models indicated that the farm would not meet the relatively stringent 36dB noise limit.  The company responded with new noise modeling that indicated they would indeed be quiet enough to meet this standard.  However, once the turbines began turning in December, neighbors found that the typical promise of not being any louder than a refrigerator in the kitchen “was a crock,” and they fired up their own hand-held decibel meters, regularly recording levels of 40-50dB, peaking to 67dB at the worst.   The county is now requiring the company to do real-world sound measurements.  The nearby neighbors insisted they aren’t against wind towers and are all for green energy, just not so close to their homes. “If they had just used a little foresight and moved these back a little farther…,” Michael Eaton said wistfully, “but they didn’t.”

Read more at East Oregonian, 3/7/09 [READ ARTICLE] The Oregonian, 3/25/09 [READ ARTICLE]

A new noise-cancelling system being developed in Germany could help to minimize what has become a major source of concern for residents near wind farms. While some noise-dampening systems are already used in turbines, they are “passive”, meaning that they reduce certain frequencies or sources of vibration noise, but do not respond “actively” to the changing frequency ranges of an operating turbine.

The new system “listens” for vibrations and then produces vibrations that exactly match, in reverse, the problematic motion within a turbine tower or base. From PhysOrg:

“These systems react autonomously to any change in frequency and damp the noise – regardless of how fast the wind generator is turning,” says André Illgen of the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Dresden. The key components of this system are piezo actuators. These devices convert electric current into mechanical motion and generate “negative vibrations”, or a kind of anti-noise that precisely counteracts the vibrations of the wind turbine and cancels them out. The piezo actuators are mounted on the gearbox bearings that connect the gearbox to the pylon. But how do these piezo actuators adjust themselves to the respective noise frequencies? “We have integrated sensors into the system. They constantly measure the vibrations arising in the gearbox, and pass on the results to the actuator control system,” says Illgen. The researchers have already developed a working model of the active vibration dampers, and their next step will be to perform field trials.

Manufacturer Quiet Revolution has completed installation of the largest-yet urban installation of its vertical-axis wind turbines, which they say are “whisper quiet.” The new installation consists of 8 turbines atop an office building, which generate enough electricity for the 200-person building. How quiet are they? Most vertical axis turbines produce less energy than utility-feeding wind farms want/need, but the promise of distributed power generation without severe noise issues is pretty enticing…. Read more at what appears to be a press-release-based post on Environmental Graffiti.

As towns, counties, and states across America work to establish permitting guidelines for wind farms, reports from many places continue to suggests that noise can be a real issue, especially within a mile of active turbines.

In Michigan, a resident near a new wind farm shares this: At 1500 ft, we thought we may be safe, but we were mistaken. I don’t know what the answer is for setbacks, but 1500 ft. is to close. Since the turbines began turning this fall, we have been amazed at the amount of noise they create. The sound is like that of a distant jet. The sound can often be heard indoors- especially at night. The nature of the noise is so out of place it is hard to mask. When we’re outside, the noise created by the turbine echoes off the buildings and seems to be amplified. When the wind is strong, the noise is masked, but about 75% of the time, the turbines are the dominant sound outside. A big concern we have at this time, is that as the weather improves (which we hope it will soon) windows will open, weather proofing will be removed and the noise that dominates the outdoors will intrude on the indoors even more. Read more from this person.

In New York, this: “When I signed the contract, I was assured there was no noise,” said Hal Graham. “”Don’t let them buffalo you. You know, I wanted to do something for the ecology. And now I can’t sleep at night, in the winter, with the windows closed. Read the rest of this entry »

In one of the first tests of wind advocates’ repeated claims that wind farms do not lower property values, a couple on Prince Edward Island asked for a reassessment, and found that their property had lost 10% of its value, solely due to the presence of wind turbines nearby. A spokesperson with the tax department said a handful of other residents living next to wind farms in West Prince also received lower assessments. Although the criteria for assessing property values doesn’t specify turbines, the department felt the properties near windmills should be treated the same as properties near industrial areas. Beverly Howard says there are now five new turbines within sight of their home, the closest about 500 metres away. “If you’re sitting out on your deck, they’re noisy, if you’re out gardening they’re noisy,” she said. “We can’t hear the surf anymore in the summertime; all we hear is windmills.” Source: CBC Canada, 12/23/08 [READ ARTICLE]
[See AEI Special Report: Wind Turbine Noise]

The Klondike Wind Rush is underway, and while wind energy is a crucial wedge in the emerging renewable energy mix, some nearby neighbors of wind farms are reporting noise levels that are higher and more disruptive than they’d been led to expect.  Simple noise models suggest noise should be inaudible beyond a quarter mile or so, but residents between a half mile and mile are quite often finding the noise intolerable.  What is going on?  This question is just the sort of thing we love here at AEI: a chance to dig in and get a big-picture view that moves beyond the strident and self-assured voices of advocacy groups on both sides of an issue.  The result, published online in March 2008, was the AEI Special Report: Wind Turbine Noise Impacts.

This report is now available as a downloadable, printable document.  Running to 30 pages in the pdf format, the report provides a comprehensive overview of issues being addressed by local planning commissions as wind energy companies seek new sites for this piece of our energy future.  We’ve also put together an 8-page pdf version that is useful as a quick overview for the public and local officials.  

See http://www.AcousticEcology.org/srwind.html for the full online report (continually updated), along with links to download the 30-page and 8-page pdfs.

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Underlying the spreading controversy about noise and health effects of wind turbines is the “million dollar question” for wind farm developers: how large a buffer must they leave between turbine towers and homes? In the US, pressure is on local and state authorities who are scrambling to write regulations to govern wind farm development, and many areas have taken the industry’s reassurances to heart, allowing towers as close as 300 meters (1000 feet) from homes. By contrast, Shear Wind, a Canadian wind developer, recently agreed to re-design an proposed wind farm to assure no turbines are any closer than 1.4km (1400m) from a residence. Read the rest of this entry »