Two recent articles in trade magazines caught me up on efforts taking place within the wind power industry to reduce the noise levels of wind turbines. While it’s great to know it’s on everyone’s mind, it also appears that so far, noise reductions are modest.

In the July 2011 issue of North American Windpower (back issues not available for online reading, sorry to say), one of the feature articles was “Turbine Manufacturers Focus on Reducing Noise Emissions.”  It included discussions with reps from most of the major turbine manufacturers, and was full of fascinating hints of ongoing research.  As the article noted:

As the so-called “low-hanging fruit” of land with good wind and transmission access gets used up and wind turbines move closer to residential areas, noise concerns are expected to become more prevalent, according to wind turbine manufacturers.

“It’s on the top of the minds for all manufacturers,” said Paul Thompson, commercial director of Mitsubishi’s wind turbine group, “we’re all doing things to reduce the amount of noise that’s generated.”  GE’s Henrik Stiesdel stressed that wind turbines do “have a noise impact.  The main remedy is to ensure that they are not sited to close to dwellings. If that’s not possible because you are in a densely populated area, then we have remedies where we control the power output when conditions are such that noise might be exceeding limits.” The article describes this system:

GE’s sound power management (SPM) works by optimizing control setting based on real-time wind conditions, according to Sean Fitzgerald. The SPM option can be configured for day and night modes, at angular intervals depending on the mode switching and based on wind turbine placement. “These applications enable the customer to specify the appropriate, desired sound emission characteristics by customizing the sound power curve to the precise requirements over the entire wind speed range,” Fitzgerald tells NAW.

Gamesa’s Miguel Angel Gonzalez-Posada notes that there’s a trend of having to keep noise as low as possible near populated areas, especially at night.

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The Roanoke County Board of Supervisors has adopted a wind energy policy that sits on the least-protective edges of current siting standards: a 60dB sound limit, and setbacks of 1000 feet from homes. Four of the five supervisors supported the proposal, saying it would protect residents; the 60dB limit was said to be comparable to sound along US 460, a four-lane federal highway in the area.

A fifth board member, representing the district where the only current wind farm proposal is sited, encouraged the board to hold off on setting absolute limits; Ed Elswick said the county should wait until it has a proposal and hire experts to weigh in “rather than grabbing numbers out of the air.” That didn’t stop him from tossing a number in the hat: he proposed that sound be limited to levels typical of rural areas, suggesting 30dB at the nearest property line.

UPDATE, 10/12/11: Elswick has asked the board to reconsider the 60dB limit; it will be on the agenda at a meeting in late October. Two board members said they knew they wouldn’t change their votes; one said he wanted to hear further discussion, and the fifth board member was not present when Elswick raised the issue again. And, 26 local residents have sued the Board of Supervisors, saying that the sudden shift from a 2600-foot setback proposal to the 1000-foot decision lacked proper notice of a public hearing, and was “clearly unreasonable, arbitrary or capricious.” UPDATE, 10/26/11: The Board of Supervisors voted to not reconsider their previous decision.

The area where 15-18 turbines are currently proposed is a section of hills about ten miles from Roanoke, a near-to-town rural enclave that has federal highways two to four miles in two directions, along with I-81 a few miles distant (see 2 mile scale at lower left, above). It appears that no existing ambient levels have been determined there, though it would not be surprising if some of the highways are faintly audible at the site.  There may well be homes in valleys, however, where current soundscape conditions are notably free of road noise, and which will now face next-to-the-highway noise levels from turbines on ridges nearby.

It is unclear at this point how many homes are close to the 1000-foot setback distance; these will be the places where the soundscape is likely to be most dramatically changed. A half-mile setback was proposed in a previous draft of the policy; this would have likely minimized the likelihood of major impacts on neighbors, though it may not have eliminated noise issues entirely. In areas such as this, it’s often hard to site wind farms without fairly relaxed noise and setback limits.  Here, as in many other towns and counties, board members apparently felt that it was more important to not exclude wind development than it was to maintain current soundscape conditions in this rural enclave.

A sprawling wind farm in northern New York state is the latest new installation to trigger push-back from neighbors complaining about excessive noise.  The Hardscrabble Wind Project is centered in Fairfield, just north of I-90 between Syracuse and Albany; its three-dozen turbines stretch across parts of three towns, covering an area of roughly ten miles by three miles.

A recent local press report summarizes the current situation: several nearby residents have complained of noise issues, leading the developer, Iberdrola, and the town of Fairfield to commission noise studies to determine what sound levels were occurring.  The Iberdrola study found that sound was generally in line with the predictions made during project planning, falling below the regulatory limit of 50dB, though in high winds some recordings came in above that with combined turbine and ambient wind noise.  The town study will take place this winter, when the leaves are off the trees.

UPDATE, 10/4/11: Good local article on the preparations for the new noise study, with a classic example of neighbors reacting differently to the sound, one saying the noise “is really bad, very hard to live with,” and another saying “to be honest with you, I don’t even notice them.”

A look at the sound assessment documents compiled as the project was being approved offers some hints as to why this project might trigger noise complaints; several factors compound the likelihood of issues here.  First is the town’s noise limit of 50dB for non-participating neighbors, which is on the very high end of regulatory limits for wind farms.  The sound assessment went through several versions as the project was revised and refined; a noise analysis from March 2009 lists 25 homes where the modeled noise levels were predicted to be between 45 and 50dB; 11 were hosting turbines and 14 were not. An apparently final revised noise analysis dated December 2009 (after some site adjustments to some turbines) does not list the affected homes, but includes very detailed sound contour maps, which show well over a hundred homes sitting in the 40-50dB zone, where it can be expected that a significant minority of residents will find the noise intrusive (based on experience at other wind farms in similar communities, and on the limited research data we have available; for more on this, see AEI’s 2010 NEWEEP presentation on community responses).  It all adds up to the classic conditions that have often led to problems in rural towns that are home to many residents who are not actively farming and ranching: too many homes receiving noise levels close to (relatively high) regulatory limits.

The final hint that there might be problems lies in the March noise assessments definition of existing ambient noise. This is often the key factor that is given too little attention in wind farm siting,

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Apparently this proposal has little chance of proceeding, but in June the British House of Lords spent two hours discussing a bill that would establish a 2km setback provision for new wind farms.  Such a setback would leave little room for new wind farms in England, but many suitable sites would remain in Scotland.

The Parliament website has the full text of the debate, replete with the always-entertaining combination of formality and shouted “interventions” from dissenting members.  Go to this page and scroll down just a bit, past the prayer and a quick “dog control notice”; the first major topic is the wind farm bill, and discussion lasts from 10:17 until shortly after noon.

This is somewhat old news, but I just heard about this workshop (thanks to Kathy Hemenway), and it’s full of useful insights: in March, the Consensus Building Institute brought together 100 wind farm developers, environmentalists, state regulators, and technical experts, including proponents and opponents of wind energy, to spend three days discussing what works – and more importantly, what doesn’t work – as communities seek to make informed and effective decisions about wind farm siting.

The quick list of take-aways posted by organizer Larry Suskind on his blog include reminders that there are hundreds of wind farms in the US that can be instructive as we plan new ones, and that it’s unrealistic to expect everyone to get behind ANY project.  Several of his bullet points sound like things that could really help reduce the perceived lack of respect for community concerns that often colors local proceedings, and so reduce the fear and resistance that accompany many wind farm proposals:

• Don’t let wind developers proceed without discussing how turbine operations might have to be restricted to reduce the risk to wildlife and the annoyance to neighbors.
• Do promise to compensate anyone who lives near a proposed facility for any decline in property values that might occur. (It is possible to buy “property value insurance” to make 100% sure that no one suffers any loss of property value.)
• Do realize that everyone reacts differently to noise and visual impacts.

And, in his most far-reaching observation, Suskind stresses the need to “Avoid the dueling experts syndrome that is so common when cases go to court.”  From the outset, he says:

It’s very clear that the traditional “town meeting” or “hearings” approach to energy facility siting is useless. Nobody learns anything at raucous public meetings…..Professionally facilitated stakeholder engagement (involving representatives chosen by the stakeholder groups themselves) can create a level playing field in which informal problem-solving is possible. This all has to be completely open and accountable.

Interesting stuff! And here’s a long blog post from one of the participants, including links to most of the Powerpoints and a lot of audio from the three days.

This is very interesting, though may get blown out of proportion: in April 2010 a District Environmental Officer submitted a memo to his Ontario Ministry of Environment superiors that offered detailed comments about the field realities he observed, in relation to the proposed Provincial wind farm siting regulations. These regulations currently guide Ontario siting, and call for at least a 550m setback, and sound levels at nearby residences of 40dB or less; the memo cites observations on the ground to recommend limits of under 35dB, and perhaps as low as 30dB.

What’s striking about Cameron Hall’s comments is that his concerns about the 40dB limit are largely similar to those of an increasing number of acousticians who have also been coming to a consensus that lower sound limits may be necessary in many rural locations. In particular, Hall noted that the regulatory 40dB limit should be adjusted downward 5dB due to the pulsing swish of turbine noise, and that it may be necessary to also factor in the acknowledged 3-5dB of error that can occur in sound modeling and the slightly variable sound output of the turbines. Combining these, Hall writes that “it appears reasonable to suggest the setback distances should be calculated using a sound level limit of 30 to 32 dBA at the receptor, instead of the 40dBA sound level limit.”

In addition, Hall stresses another factor often brought up by those trying to understand why 40-45dB turbine noise is stirring up so many complaints: the fact that rural soundscapes in his district are often as quiet at 20-25dB, and noise intrusions should be kept to less than 10dB over that; this leads Hall to similarly suggest Read the rest of this entry »

The island community of Vinalhaven, Maine, remains embroiled in a contentious wind farm noise controversy nearly two years after three turbines began operating there.  The nearby Camden Herald-Gazette recently provided a good, detailed overview of the latest rounds of the back-and-forth between nearby neighbors, the local electrical coop that buys the energy, and state regulators.

An escalating legal tussle has developed since the Fox Island Wind Neighbors paid for noise monitoring and submitted data to the state indicating that the turbines were at times exceeding their regulatory limit.  The most recent salvo is a complaint filed in state court charging that state Department of Environmental Protection commissioners have overstepped their authority by over-ruling staff recommendations on how to deal with the violations.  The neighbors charge that compliance recommendations were watered down, and, most recently, requirements that Fox Island Wind prove ongoing compliance were removed.

The complaint details the unfolding disagreements, beginning in April 2010, continuing through September 2010 when the state DEP officially reported that the turbines were out of compliance by a few decibels in some conditions. Since that time, the complaint charges that three successive DEP Commissioners have meddled in the compliance process, culminating most recently when, according to the petition, “Acting Commissioner Aho, over the objection of DEP professional staff, and in direct contradiction of the findings in the November determination of noncompliance letter, issued a compliance condition order.” The petitioners are asking the court to vacate Aho’s order and replace it with an order drafted by DEP staff, and to review the alleged instances of political intervention.

The article linked above contains extensive quotes from the complaint, as well as from Fox Island Wind, the local developer of the project.

Meanwhile, as part of ongoing efforts to seek innovative solutions short of curtailing operations, the local turbines are in the process of being modified by GE, their manufacturer.  Crews are applying serrations to the trailing edge of the blades; this experimental technique is designed to improve air flow off the blades, thereby reducing noise output by 2-4dB.  See this 2008 AEInews post about earlier research into such techniques.

Throughout the controversy, including in this article, Fox Island Wind has often returned to the idea that the ambient noise of wind in trees is a key factor in the higher recorded sound levels, while neighbors insist that the turbines are clearly heard through this ambient noise. In many ways, the Vinalhaven situation is a perfect example of one of the key, and often-overlooked, factors in wind farm noise debates: the regulatory limit is high enough that even when in compliance, turbines can be clearly the loudest thing in the local soundscape, triggering severe annoyance reactions and sleep disruption for nearby neighbors. While the legal sparring focuses on a 1-3dB violation of the operating standards (a difference in volume that is barely perceptible at best), the underlying fact is that even the allowed 45dB is too loud for many of those living within a half mile or so.

A couple of in-depth reports on communities roiling with wind farm controversies are currently viewable online.  Both seem to present a fairly balanced story, featuring locals struggling with noise, locals and consultants who see the problems as minimal and wind development as necessary and important, and some government officials trying to make sense of it all. My reaction to the first one, Against the Wind, is below; I’ve yet to complete the other, a much longer series from the UK entitled Blown Apart: Wind Farm Wars, which appears to consist of four hour-long segments.

From Australia comes an hour-long investigative report from Four Corners, a 60 Minutes style weekly TV program. The report, entitled Against the Wind, can be viewed here (transcript also viewable online). Both of the featured families who are negatively impacted come off as reasonable folks, not hot-headed complainers or people caught up in fears seeded from internet research. One of them is Noel Dean, a fairly well-known name among those tracking these issues from afar (on the internet, yes!), and the others are Carl and Samantha Stepnell.  Dean and the Stepwells both abandoned their homes due to noise and severe physiological reactions, though they return to work their farms. The Stepnell’s home is 900 meters (over a half mile) from the nearest turbine, with three others within 1200 meters (about three quarters of a mile); they weren’t affected right away, but after about six months began being affected. Though they tried to ignore it and live with it, the were soon being awoken most nights and having headaches and other stress responses.  The stories told by Dean and the Stepnells are familiar to many others within a kilometer or two of wind farms.

The show also includes a glimpse of some recording done at Dean’s home by Graeme Hood, where there was significant energy at lower frequencies, but not as much deep infrasound as Hood had suspected would be needed to account for some of the impacts.  There are clear statements of many of the also well-known responses from industry and pro-wind folks, about the lack of clear data on any negative impacts, as well as footage of an event held by a community group that includes provocative images of burning turbines and distressed speakers urging the whole industry to be “shut down, everywhere” due to health concerns.

While the content of the show is fairly representative of the two sides of the controversy, it slips some in places,

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As regular readers will know, the National Park Service completed an epic planning process earlier this year when it released proposed rules governing air tours at Grand Canyon National Park.  After over two decades of discussion, including a failed attempt at coming to a consensus decision with all parties a few years back, NPS planners came up with an approach that was generally well-balanced.  It allows airplanes and helicopters to remain a strong presence in the park, with 8000 more annual flights being allowed than have been occuring in recent years, and half the park still hearing aircraft throughout most of the day.  On the plus side of the ledger for quiet recreation is a groundbreaking no-fly period for an hour after sunrise and an hour before sunset, a window of peace and quiet that will transform the back-country experience for the entire park.  And, flight corridors in two popular back-country areas will alternate seasonally, so there is a time of year in each when it will be noticably more serene.

Nevertheless, the air tour industry claims the plan will put them out of business; it’s not at all clear how this could be, given the greater numbers of flights.  I wonder whether the sunset period is especially popular for flights; if so, this could be a bitter pill for air tour operators to swallow.  Yet it’s hard to deny that this is a time of day when river runners and hikers will find their experience immeasurably improved when birds, wind, and water are the dominant features of the evening soundscape.

Heeding the air tour griping, four Congressmen, two from Arizona and two from Nevada, have added an amendment to a Department of the Interior appropriations bill that would strip all funding for implementation of the rule.  Earlier, the region’s two most powerful Senators, John McCain and Harry Reid, signed a letter opposing the plan, and McCain also attempted (and failed) to push through an amendment blocking it.  For more on the current amendements, see this editorial in the Arizona Republic and this post that details objections from other Arizona representatives and the National Parks Conservation Association.

A couple of articles in this month’s Wind Power Engineering caught my eye.  What follows is more speculative than what you normally find on AEInews, but with that in mind, I encourage you to check the articles out yourself.

Both articles address basic issues regarding wind turbines: the wakes they create downwind, and normal wear and tear of turbine blades.  Neither one considers noise impacts at all, and I don’t have the engineering background that might allow me to make truly informed extrapolations.  But both certainly seem to be worth bearing in mind as project planners and managers address possible noise issues.  The main thing I wonder is whether either of these factors might make turbines slightly louder than expected, or than modeled under more ideal assumptions.

The first article covers a topic we’ve covered here at AEInews before: ongoing research into the turbulent wakes that stretch out downwind from wind turbines:

Today’s massive wind turbines reach into a complicated part of the atmosphere, Julie Lundquist expalins. “If we can understand how gusts and rapid changes in wind direction affect turbine operations and how turbine wakes behave, we can improve design standards, increase efficiency, and reduce the cost of energy.”

The second article focuses on routine maintenance of wind turbine blades, and explains some of the normal wear and tear that needs to be attended to.  It seems likely that at least some blade imperfections would add extra noise, which is of course largely caused by the airflow coming off the blades.

Traditionally, less attention has been paid to the repair and upkeep of turbine blades versus other components. Instead, preventive maintenance programs have focused on the internal mechanics of turbines due to the predictability of their maintenance requirements. Typical preventive maintenance plans for internal components fall into 3, 6, and 12-month work schedules. By nature, blade repairs are more difficult to plan. Blade damage can arise in manufacturing, transportation, and tower construction and erection. However, maintenance issues more often occur in the field from leading-edge erosion, weather, and other factors. A lack of predictability and historical data complicates preventive maintenance for blades.

Commercial turbines can have tip speeds of over 200 miles per hour. At these speeds, rain drops can take on the impact of small stones, and blowing sand has the erosion power of a plasma cutter. Studies have shown blade roughness and accumulated debris on the blades can reduce wind turbine performance by 5 to 30%. Blades that aren’t working efficiently can also create vibration that contributes to gearbox failures.

Joshua Crayton, a contractor who provides blade maintenance services, notes that regular inspections are especially important in windy seasons and following lightning storms. “Operators and owners are inheriting their wind farm assets and the responsibility of maintaining blades that are no longer covered by the (manufacturer) warranty,” he says. “Like any business, wind farm owners and operators typically run a lean staff and may not have an experienced maintenance technician in-house. Partnering with a service company can help them design a long-term, post warranty, preventive maintenance plan.”According to Crayton, a maintenance plan should be initiated before the warranty period expires. “A thorough internal and external blade inspection should be scheduled in the warranty period,” he says. “Once owners and operators take over care of a wind farm, these inspections should take place every two years. Personnel can conduct simple ground inspections while on-site, but there is no substitution for a close, visual examination performed uptower.”

PLUS: Two other short articles may also be of interest: one on design concepts for a 20MW turbine (today’s big ones are 2MW), and the other a very positive development, a 36MW battery designed to stablize output to the grid from wind farms.

The UK wind industry is scrambling to respond to a High Court ruling that affirmed the legaltiy of conditions placed on the Den Brook wind farm near Devon, limiting ampltude modulation of wind turbine noise to a level that could be very hard to comply with.  After years of pooh-poohing the reports of neighbors who said that the pulsing quality of the turbine noise made it especially hard to live with, including a much-criticized study a few years back that found nearly no AM at UK wind farms, Renewable UK (formerly the British Wind Energy Association) is fast-tracking a far-reaching study of AM, which they hope to complete in just seven months.

The new study, funded by Renewable UK (a trade organization of wind industry companies), aims to develop better models for predicting AM, including assessment of the effects of high turbulance and closely spaced turbines, as well as noise predictions both nearby and at a distance.  In addition, they aim to develop a listening test that could inform a possible penalty-assessment approach to dealing with AM noise when it does occur; such an approach, common in many regulations, forces the overall noise level to be lower when AM is present.

After years of claimng there is no need to assess or regulate AM, it appears that the industry has now found itself sufferering the consequences of denying the problem.  Instead of working to create regulations that take the issue seriously (whether or not it is common), the industry is now vulnerable to being out of compliance when AM does occur.

The recent ruling unfolded along just these lines.  The wind developer claimed noise would be inaudible or at least not problematic, while local resident Mike Hulme was unconvinced and wanted to be sure that if AM did occur, there would be consequences for the wind farm.  His acoustical consultant Mike Stigwood told the Noise Bulletin: “I devised an excess amplitude modulation condition based on my findings and measurements at other wind farms that was worded simply and made an exceedence a breach. It was a simple stand-alone condition.” In an earlier round of litigation on these conditions, the developers proposd a penalty approach to dealing with non-compliance (thus seemingly implying that AM could occur), but the Inspector who wrote the rules did not incorporate their proposal, because he felt the proposal lacked necessary detail to apply effectively.

While the High Court ruling denied the appeal’s goal of stopping the Den Brook wind farm from proceeding, it affirmed the validity of the AM condition and stressed that the wind farm must comply with the rules as written, which are very stingent: whenever sound levels are over 28dB, turbine noise (measured in very short time intervals) can’t vary by more than 3dB.  To avoid penalizing random momentary fluctuations, the AM provision applies only when this pulsing of sound occurs more than five times in two minutes, and for at least six minutes in any hour.

While ruling that the condition as written was valid, the Court said that there was no provision in the ordinance that would allow any sort of penalty or other way of dealing with non-compliance with the AM limit, short of shutting down or changing operations so as to remove the pulsing sound. It’s likely that this High Court ruling will provide precedent and justification for the development of ordinances that do address Amplitude Modulation as a particular quality of wind turbine sound, and that future ordinances will be developed with a penalty scheme to minimize the negative effects of this pulsing quality of wind turbines, by requiring them to be quieter when AM is present; in practice, this is likely to mean that wind farms will need to be built a bit farther from homes, so that their noise is quieter all the time, leaving room for AM factor to be added without breaking the noise limits.

For more, see this article in The Environmentalist, a leading UK magazine, or read the High Court ruling here. Also fo note, the June 2011 edition of Noise Bulletin includes an in-depth article on the court case, along with a good summary of the Wind Turbine Noise 2011 conference, including a sidebar introducing the industry-funded AM research program; Noise Bulletin is not viewable online, but free sample issues and trial subscriptions are available on their website.

An Ontario Environmental Review Tribunal has ruled that the Kent Breeze Wind Farm can be built, denying an appeal by the a local resident and a community group that challenged the wind farm’s permits, largely on the basis of health effects that it may cause among nearby residents. Since Kent Breeze is the first wind farm to be approved under Ontario’s new green energy development rules, this was seen as a key to near-term wind development in the province.

The Tribunal’s 223-page ruling provides a fascinating, in-depth look at the state of current wind farm science and policy; many pages are devoted to the testimony of each of the witnesses, which included well-known researchers with a wide range of viewpoints, including Rick James, Geoff Levanthall, Christopher Hanning, Robert Colby, and many others.  I highly recommend that anyone interested in these issues download the full report and give it a look.

An article in the Windsor Star includes predictable responses from all concerned. “We are pleased with the decision of the tribunal,” said Jennifer Lomas, spokesperson for Suncor, the developer. “In terms of the alleged health concerns, we are committed to understanding the interaction of our operations and the environment. We meet all operating standards for these projects, this includes strict compliance to regulatory (rules).” Meanwhile, John Laforet, head of Wind Concerns Ontario, stressed that “(The tribunal) said there were risks and uncertainties. We aren’t debating whether there is a problem or not, but whether there is responsible development. We want believable studies and setbacks based on the outcomes of those studies…We are hopeful this ruling, while it’s a battle lost, it’s a step toward winning the war provincewide.”

Indeed, the Tribunal stressed in its ruling that “It is hoped that the legitimate debates surrounding the effects of turbines will spawn further independent research to the point that some of the challenges posed in this Hearing will be reduced over time.”   Futher, “The Tribunal accepts that indirect (health) effects are a complex matter and that there is no reason to ignore serious effects that have a psychological component.” This is a stark contrast to the CanWEA/AWEA health effects study, which focused nearly solely on direct health impacts, dismissed indirect effects triggered by annoyance, stress, or sleep disruption as insignificant or subjective, and concluded that there was scant reason to look deeper at the issue.

Click on through below the fold for AEI’s in-depth summation of the key points made in the full ruling.

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The Syracuse Post-Standard reports that a study of real estate sales in three upstate New York counties has found that being closer to wind turbines can lead to reduced sales prices.  In two of the three counties, property values appear to have dropped by 8-15% for homes situated a half mile from the nearest turbine (which usually means several more are within a mile or two); the price drop was only slightly less for homes within a mile, while there was a smaller, 2-8% drop for homes within 3 miles of a turbine.  However, the third county studied showed no price reduction after the wind farm was constructed; the authors found that in this county, prices actually rose a bit just after construction, then settled  back to no significant change. This study uses a hedonic analysis methodology similar to two previous studies (Hoen and Hinman) that found no significant price change.  This new study, by Martin Heintzelman and Carrie Tuttle of Clarkson University, differs from the previous studies in that it does not combine all results, but rather looks at each county individually.

The Heintzelman study is still being finalized; an earlier version that combined all locations into an overall negative impact has circulated since March, but a new version that separates the locations and finds the more nuanced results is now available.

Riga, Michigan has adopted a wind farm ordinance that limits noise at nearby residences to 45dB during the day and 40dB at night, and the wind developer says they cannot meet these limits on the land they’ve leased.  The rules also establish a distance limit of 4x the height of the turbines; this amounts to a bit over a third of a mile. There’s a good chance that wind boosters will spur a township referendum to repeal the new rules.  Three other local townships where wind development is planned are working on ordinances, and there is some indication that they will come to a similar conclusion about acceptable noise levels.  It is not clear from initial press reports whether the Riga ordinance includes the option of obtaining permission from willing landowners to build closer or allow slightly more noise at their homes.

Joshua Nolan, director of the nonprofit Interstate Informed Citizens Coalition, said “The ordinance as it exists is probably the best compromise.” With many acousticians suggesting a 35dB night time noise limit (see recent AEI Wind Farm Noise 2011 report), and the industry more accustomed to building wind farms to meet a 45-50db threshold, the Riga ordinance is a moderate attempt to provide more noise protection for neighbors.  Yet it may also be a good illustration of the fact that such protection can indeed preclude development in some rural areas with more population density than the wide-open west.  Many towns and counties are attempting to find the middle ground where development can take place, but citizens are not unduly impacted by noise; in some areas, there may not be enough room to keep turbines far enough from homes to meet this goal.  In this situations, the localities will need to decide whether wind development or local peace and quiet is more important to them.  In some areas, it may be possible to find enough willing neighbors to accept louder noise at their homes to allow smaller wind projects to proceed, while keeping turbines noise to 40dB, or even 35db, at homes of those who wish to maintain the current rural soundscape.

The past week has seen a flurry of new reports and articles that aim to debunk the idea that wind farm noise should be taken seriously as a concern when siting new wind farms.  AEI’s upcoming Wind Farm Noise 2011 report will address the issue in great depth when it’s released in about a week, but for now I wanted to make a few comments about the recent releases.

Two reports came from Canadian environmental groups that advocate expansion of wind energy and are frustrated by local resistance, especially in Ontario.  I share their support for wind energy providing an increasing percentage of our electrical generating capacity, and have little problem with the bulk of these reports; but in each case, I feel that their treatment of noise issues misdirects attention away from the very real problem at the core of the debate: when wind turbines are built closer than a kilometer or so from homes in rural areas, a high proportion of those nearby neighbors experience significant quality of life impacts due to audible turbine noise.

Sierra Club Canada released a 40-page report Read the rest of this entry »

This column was published recently in the Record-Patriot (Frankfort, Michigan).  It offers a pretty solid short version of AEI’s current perspective on wind farm noise issues.

Windfarm noise: Moderate, but often disruptive
Guest Viewpoint by Jim Cummings, Executive Director, Acoustic Ecology Institute

Some local residents asked me to take a look at the recent Guest Viewpoint from Duke Energy about the planned Gail Windpower Project, and to share my experience in studying community responses to similar wind farms in other parts of the country. The Acoustic Ecology Institute produces analyses and layman summaries on various noise-related issues; after assessing a wide spectrum of reports, scientific studies, and personal accounts, our goal is to present a picture that helps makes sense of the confusingly differing viewpoints held by those who are strong advocates for one side or the other. This column will draw on an in-depth presentation on community responses to wind farm noise that I put together at the request of the New England branch of the Wind Powering America program, a wind advocacy project of the US Department of Energy. The full presentation can be found at https://www.aeinews.org/archives/972

Wind farm noise issues are subtler than the anti-wind groups may fear, but much more real than the industry would like to believe. Note that I don’t say “than the industry would like you to believe.” In general, I don’t see the industry as fostering mis-information, so much as being overly satisfied with information that is becoming outdated, especially as we get more experience with community reaction in the upper midwest and northeast. See this column from Renewable Energy World for more on the shift that is taking place: https://www.aeinews.org/archives/1236

The bottom line, based on what we’ve seen in other communities, as well as what I’ve heard myself when visiting wind farms (including the truly impressive Sweetwater wind farm region mentioned in the Duke column), is that wind turbines are often clearly audible to a half mile or so, and somewhat audible beyond that, out to a mile or so at times, depending on wind and topography. At distances beyond a few hundred feet, the noise is never what we’d call objectively “loud,” but it is, with some regularity, notably louder than other existing ambient noises, especially in rural landscapes where there are no roads with steady traffic within earshot. It’s long been recognized that when a new noise source approaches 10dB louder than existing ambient, it will trigger widespread negative responses. That’s at the core of today’s increasingly vehement debate about wind farm noise impacts. As many wind farm neighbors have noted with surprise, 45dB can seem startlingly loud in quiet rural areas! Read the rest of this entry »

A recent article in the New York Times focuses on the financial benefits coming into communities in eastern Oregon, where wind energy development is booming despite state noise limits of 36dB at homes. Most wind farms in the US and Canada face noise limits in the 45-50dB range, with some regs going as low as 40dB at night; wind industry representatives generally claim that lower noise limits will preclude wind development. Oregon’s approach to wind farm siting, which imposes a cautionary noise limit to protect residents from unwanted noise, while allowing for easy exemptions when residents are willing to live closer to turbines, appears to AEI to be a constructive response that addresses concerns about protecting the rural soundscape while also encouraging wind development.

Ione, Oregon wind farm; Leah Nash for the New York Times

In Sherman County, landowners earn $5500 per year per turbine, often hosting ten or more per landowner, often in wheat fields.  The County earns enough in taxes and fees to keep schools flush with cash, and issue a modest annual check to all heads of household.

While a 36dB noise limit aims to keep audible turbine noise close enough to existing quietest background ambient levels to be relatively unobtrusive, it should be noted that some residents report noise levels well above 36dB at times, suggesting that the noise modeling used in laying out the wind farms may have been faulty.  Apparently, even with the lower noise limits, some homes are within a half mile of turbines, a range in which turbines are often easily audible and can sometimes cause sleep disruption.  The state law allows companies to obtain waivers from residents in order to build closer and create to noise levels over 36dB, and some wind companies are seeking such waivers from nearby neighbors, in exchange for one-time or recurring payments.  These waivers could also protect companies from situations in which actual noise levels rise slightly above the levels predicted by pre-construction noise models, as recently occurred at the Willow Creek Wind Farm in the same region.

Thanks to Google News’ nifty customized news sections, I hear about articles worldwide that contain terms interesting to AEI, such as “ocean noise,” “wind turbine noise,” and, yup, “Acoustic Ecology.”  Yesterday I saw that David Colby, one of the authors of the widely-read report on wind turbine health effects, had responded to an article that questioned his integrity on that project.  It sounded like his self-defense was justified, but for some reasons in his defense he noted that while AEI had critiqued the report, our comments should be disregarded because we are “wind objectors.”

Well, having invested considerable time and effort in establishing a reputation as an honest broker of the science and policy debates surrounding various noise-related environmental issues (with DOE’s NEWEEP, NOAA, US Navy, Canadian DFO, and others affirming that by inviting my participation in public and private workshops and working groups), I was rather offended by his characterization.  I quickly submitted a letter to the editor noting that AEI believes wind energy is an important part of our energy future, and that our focus on noise issues has from the start been focused on the idea that if impacts on nearby neighbors are not taken seriously, the future growth of the industry will be jeopardized.  In several road trips over the past year, I’ve come across large wind farms in Texas, Iowa, Nebraska, and Wyoming, all of which were truly impressive and made a lot of sense on the landscape where they were.  Nearly without exception, they were also miles from any homes.  It’s only as we move wind farms into rural areas that are not primarily working landscapes that we’re finding a significant proportion of folks within a half mile or mile saying that their quality of life is being affected by the noise (which is, in my experience, nearly always clearly audible at a half mile, and barely audible at greater distances).

Here’s my brief letter in defense of AEI’s balance, and here’s AEI’s initial critique that Colby refers to, which seems to me to be quite measured, and in fact supportive of much of what they found.

A couple on Wolfe Island, Ontario are asking their local officials to reduce the valuation of their home by about 17% due to its proximity to a wind farm that began operating two years ago.  Wolfe Island is in the St. Lawrence, and sits a couple miles from the New York town of Cape Vincent, where another wind farm is planned.

Ed and Gail Kenney had their home assessed at $357,000 just as the wind farm construction was beginning; a more recent appraisal in early 2010 came in at $283-295,000; the appraiser said she took the proximity of the wind farm into account. The Kenney’s home sits just over 1 kilomerter, or six-tenths of a mile, from the nearest turbine.  Their claim asserts that the lights and the noise from the turbines are the factors that reduce the value.

A witness for the Municipal Property Assessment Corporation, which disputes the reduced valuation, and maintains that the 2008 assessed value is still valid, cited property sales in Dufferin County where 133 turbines are now operating.  Seventeen homes have sold, though the distances were not stated; four sold for more than the initial asking price, and the others showed no clear relationship to proximity to turbines, so “there’s not enough evidence to warrant a negative adjustment.”

UPDATE, 4/16/12: The Assessment Review Board ruled that proximity to wind farms should not be a factor in county assessments of properties. The Kenneys claim that virtually no homes have been sold near the turbines on Wolfe Island since the wind farm became operational.

UPDATE, 7/3/13: The latest update from Wolfe Island suggests that 78 properties have seen substantial reductions in assessed value between 2008 and 2012; most are within 2000 feet of turbines, though turbine proximity is not cited as the reason for the reductions. See more here

As noted in AEI’s previous coverage of property values research, while there is little evidence of decreased property values due to seeing turbines in the distance, there is less clarity about whether values decrease within a half mile or mile, where noise issues become a factor.  As in the Dufferin County sales, there are  generally too few sales at close range to produce statistically significant trends one way or the other. In 2008, several property owners near a Prince Edward Island wind farm had their property values reduced by the town by about 10%.  Developers of two different wind farms in Ontario – one of the Dufferin County farms and one in Ripley – have purchased several homes from neighbors after they found noise of the turbines disruptive. UPDATE, 10/1/11: This story from the CBC discusses several homeowners in Ontario who have been unable to attract buyers or who sold for a loss after a wind farm began operating nearby (including four of the homes bought by developers).

At most of the places where the National Park Service and FAA have commenced air tour management planning (ATMP), there is already a deeply entrenched local air tour economy, as well as a visitor expectation that they can take flight in order to see the beauty from above.  The Grand Canyon is of course the Mother of All Overflight Controversies; similarly, the the Black Hills/Mt. Rushmore and Hawaii Volcanoes ATMPs also dove into situations where thousands of annual flights were already taking place.

But now for something completely different: At Mt. Rainier National Park near Seattle, only 114 flights are currently allowed each year, with actual numbers apparently lower.  This provides a rare opportunity to give real consideration to Alternatives that truly maintain natural quiet on the mountain.  The Park is currently accepting comments on a set of draft alternatives for use in the ongoing EIS process.  Two of the proposed alternatives would greatly reduce noise in the park backcountry: Alternative 1 simply bans all flights over the park, and Alternative 4 keeps planes to the far periphery of the park, and at high altitudes.  Alternative 3 allows 55 flights per year to circle the peak, and introduces the NPS’s recent innovation (being spearheaded at the Grand Canyon) of setting aside no-fly times – in this case, weekends, and sunrise/sunset on Monday-Thursday, and keeps planes at 2000 feet or more.  Alternative 2 maintains current use patterns around the peak, capping flights at 114 per year.

Truthfully, any of these options will maintain Mt. Rainier as a place where hikers can experience the natural soundscape with minimal intrusion.  But, the opportunity to establish a precedent for keeping commercial air tours out of relatively pristine National Park lands is one that is worth keeping on the table; we encourage support for the inclusion of the “no air tours” alternative.  Comments are being accepted through May 16.

NPS Mt. Rainier ATMP page ; Mt. Rainier Draft Alternatives

And remember, comments are being accepted through early June on Draft Alternatives at Hawaii Volcanoes National Park, too.  There, Alternatives range from 28,000 flights per year to “no air tours” (though this will allow flights around the periphery, and over 5000 feet within the park).  You can read about the process and comment here, and you can download the alternatives here.

Suncor and Acciona Energy recently purchased four homes near the 38-turbine Ripley Wind Power Project, buying out several neighbors who had been pushing the companies to deal with noise issues at their homes.

According to The Kincardine News:

The Ripley-area residents had approached municipal council in 2009 about a rash of health problems, “including high blood pressure, headaches, sleep disturbances, the sensation of bugs crawling on the skin, humming in the head, non-stop ringing in the ears and heart palpitations,” they believed were caused by their proximity to the project.

“We take the concerns of all our stakeholders seriously,” said Acciona’s Paul Austin, adding they’ve been working with local stakeholders to answer questions and understand their concerns since the project began. “After a prolonged period of consultation that involved a number of third-party studies and tests, it was agreed upon that the only solution that could meet the needs of this small group of local landowners was to purchase their homes.”  Austin also stressed that the buyout was not linked to health issues, or, more precisely, he said that  “no link between the operation of our Ripley Wind Power Project and the health concerns of our neighbours could be discovered, and so no damages were awarded or necessary.” (ie, no damages were paid; yet the houses were purchased)

Interestingly, the sales prices were significant, yet appear to be something that the developers feel they can take on as part of the cost of doing business in this area: the homes were purchased at agreed-upon market rates of $230K, $250K, $165K, and $400K. (see this post for link to real estate sales records obtained by a local anti-wind group)

Maine’s Office of Energy Independence and Security has delivered a long-awaited report on wind farm siting to the state legislature.  The lead recommendation is that the minimum distance between commercial wind turbines and residences be nearly doubled, to 1000 feet; current standards are based on safety, not noise, while the proposed increase is meant to address noise impacts.  It appears that the 1000 foot distance is based on keeping noise levels below 55dB during the day and 45dB at night, which is what is required for all noise sources in rural Maine.

The proposal was met with resistance from both sides.  Jeremy Payne of the Maine Renewable Energy Association said the new setback is arbitrary, and that “we’re comfortable that the existing setbacks are protective of public safety and health.” Karen Bessey Pease of Friends of the Highland Mountains, which has been proposing one-mile setbacks, said that 1000 feet is “just too little to protect citizens.”  David Wylie of Vinalhaven (image above) was more blunt: “One thousand feet is really ludicrous. We’re 2,400 feet away and it’s really unbearable. It shakes the house and goes through our bones and bodies.”

Here at AEI, we noted that the experts consulted for the report did not include any acousticians who have suggested that lower noise limits may be necessary for wind farms than for other noise sources.  We were pleased and somewhat surprised to see AEI cited numerous times, though in some cases our points were taken partially out of context and some points which were accurately presented were apparently ignored in coming to the conclusions. In particular, we were pleased to see that the report included our assessment of peer-reviewed Scandinavian studies that suggest that when wind turbine noise tops 40dB, annoyance spikes in rural areas to 25-45% of those hearing these levels – though of course the 1000 foot setback guarantees that many of the closest neighbors will indeed be disturbed (it’s likely that those from 1000 to at least 3500 feet will regularly hear noise levels of over 40dB).  Two citations of our work implied that very few wind farms cause noise issues, but left out the fact that this is because most are far from homes and that a much larger proportion of wind farms within a half mile or mile of homes do cause problems, especially in rural areas that are not working farm and ranch landscapes.  Likewise, a citation suggesting that “Typically, between 5-20% of people, with higher levels of around 20% of people in rural areas, are highly annoyed by wind turbine noise” neglected to note these figures are for all those who can hear turbines at any volume or distance; again, the key point is obscured: that those within a half mile or so are apparently negatively impacted at a high rate, and those within a mile or so also likely to be more bothered. Even overlooking the subtle misinterpretation, I am left to wonder: is this report suggesting that causing a high level of annoyance in 20% of the rural population an acceptable outcome?  As noted by many acousticians, community noise standards are typically set to minimize negative impacts more effectively than that.

Read more at the Portland Press Herald, or: Download the full report.

It’s “wind week” at the Maine state legislature, where the Utilities and Energy Committee is hearing two days of testimony on a slate of 14 bills that have been introduced to regulate wind energy development.  One bill would mandate property value guarantees, and another would impose setbacks of a mile and a quarter from homes.  Maine’s been a hot spot for community noise issues, with a ridgeline wind farm in Mars Hill spurring noise and health complaints from most of the residents within a half mile or so, and a three-turbine farm in Vinalhaven triggering noise issues for around half of the similarly nearby neighbors.

Legislators heard starkly differing views from supporters of the wind industry and community groups that have been pushing for more protection for landowners who don’t want to hear turbines from their homes.  Predictably enough, the rhetoric was at times extreme, with one opponent positing that development up til now has been “a well-planned legislative fraud perpetrated on the citizens of Maine.”  On the other side of the coin, a local realtor said, “I have seen no negative impacts whatsoever on real estate values in Mars Hill,” but didn’t specify whether any of the homes within a half mile or so that have been severely impacted have been on the market.  (Ed. note: while most evidence agrees that prices of homes a mile or more from wind farms are not dramatically affected, there is less clarity or consensus about the few homes within a half mile or mile; in rare cases, homes in this range have been abandoned by owners.  It’s clear that easy reassurances about impacts in the community at large, ie within several miles or within sight of turbines, often don’t reflect the experiences of those living closest.)

The Portland Press Herald and  Bangor Daily News have more coverage of the hearings, including this exchange:

Several people living near wind power facilities questioned whether a few hundred temporary construction jobs is a worthwhile trade-off when the turbines force some homeowners who support the local economy year-round to move away.

“I’m listening to employee after employee come up and say, ‘I’m more important than somebody’s home,’” said Carrie Bennett, who lives near a three-turbine facility near Freedom. “Do you want to buy my house? Do you want to live in my house? Of course not.”

Researchers have determined that Americans between 25 and 64 years old hear better than their grandparents did at the same age.  Comparing research done in 1959-1962 with similar studies in 1999-2004, it appears that upper-frequency hearing is notably better than it used to be; middle-frequency hearing is roughly the same.

Researchers suspect that a combination of better treatment of childhood ear infections, fewer smokers and better health care in general, and a reduction in manufacturing jobs (as well as better hearing protection in today’s workplaces) have led to the improvement.

The reduction in upper-frequency hearing loss is especially important in speech recognition.

Women from three generations converse (NIDCD)

For more, see this NIDCD press release and this post on About.com that includes several related links.

Traffic noise is the second biggest environmental problem affecting our health in Europe, after air pollution, according to a report published in late March by the World Health Organisation (WHO). According to the WHO study, 1.8% of heart attacks in high income European countries are attributed to traffic noise level higher than 60dB.

“This new health evidence highlights the urgent need to reduce transport noise”, says James Grugeon, Chief Executive of Environmental Protection UK. “EPUK are working to reduce noise from road traffic. Our Campaign for Better Tyres, launched this week, encourages transport operators and drivers to choose tyres that are quieter.” The European Commission is expected to release a proposal in June for more stringent vehicle noise standards, and from November 2012 new regulations for stricter tyre noise levels and tyre labeling for noise come into force.

European citizens are well aware of the health impacts of traffic noise. According to a recent Eurobarometer (6), almost half of all Europeans believe that noise affects their health “to a large extent” and another one-third said that it affected their health “to some extent.”

Source: Environmental Protection UK

Download WHO report here