For the past three years, I’ve been learning what I can about the ways that wind farm noise affects nearby neighbors.  While most online information tends toward the black-and-white—the sound levels are lower than most human noise sources and current siting standards are fine; the noise is invasive and we need to totally rethink the efficacy of wind energy—AEI has been dedicated to fleshing out the shades of grey. A noise that drives one person crazy is considered a gentle whoosh by another; ranching areas tolerate wind farm noise at levels far above those that are causing problems in rural areas where residents especially value peace and quiet; community noise standards that minimize complaints about, say, road noise, can appear to be too high for wind farms.  As important as it is to tell the whole story, including the fact that much is yet unclear, I feel a bit adrift in the grey these days. When it comes right down to it, how does one describe a shade of grey?

In the coming months, AEI is going to take a different approach.  More to the point, I’m going to focus my energies toward a different purpose, a new task.  Rather than trying to “tell the story” in a way that helps everyone see the issue from a larger perspective, I’m going to use my time and energy to put together a toolkit aimed at providing the necessary information to allow anyone to come to their own conclusions: an annotated collection of concrete information about the sound levels and varied community responses observed around wind farms. Given the limits of what one person can do, it probably won’t be totally comprehensive, but it will draw from the full spectrum of researchers and experiences, and will attempt to provide some context to understand what is known, what is mostly unknown, and where we might most fruitfully direct further investigations.

I think that AEI’s publications over the past couple of years have done a fairly decent job of telling the big-picture story of wind farm noise. The various presentations, articles, and reports have taken different approaches toward a common goal: to explore the paradoxes and subtleties that belie both the black and the white views.

Read the rest of this entry »

AEI Commentary

The wild and turbulent public debate about wind farm noise issues continues to generate steady new eruptions in Ontario.  And while what’s coming out could be extremely valuable information for others struggling to support a more cautionary approach to wind farm siting, media reports are contributing to an increasingly jumbled public perception about the troubling health impacts that some wind farm neighbors have experienced.

Ironically, the spotlight currently shining on Ontario could be shedding a clear, focused light on the shortcomings in current siting standards – even Ontario’s relatively stringent ones. That light would reveal regional regulatory staffers raising concerns about whether the standards as currently applied are in fact protecting residents from undue disruption by wind farm noise, increasing anecdotal evidence from homeowners and realtors that wind farms make it harder to sell homes at their fair value, and telling examples of homes bought at market value by wind developers and later sold at large losses.  Instead, these important and fascinating stories are being jumbled into a far less coherent mess of public perception, with negative health impacts becoming the dominant theme. (See the final paragraphs of this post for AEI’s prescription for moving forward more constructively.)

As real as the health effects can be — there’s no doubt that some nearby neighbors have struggled mightily with them, to the point of leaving their homes to find relief — it doesn’t serve the public to conflate every noise complaint with a health complaint, or to distort the sources of noise complaints to make the suffering of the most afflicted appear to be far more widespread.  This is, unfortunately, the effect of recent media reports from Ontario, Read the rest of this entry »

David Dunn is a longtime friend and colleague to AEI here in Santa Fe, and in fact his underwater insect recordings were my first taste of the sounds of the natural world having the potential to be deeply strange and amazing, rather than “just” beautiful. So when he discovered that the bark beetles chewing their way through the piñon pines in the hills of New Mexico were making all sorts of bizarre sounds, and suggested publishing a CD to benefit AEI, I was all for it.

Since then, the bark beetle inquiry has taken on a life of its own, becoming a perfect expression of David’s longtime conviction that artists can contribute in significant ways to science.  The acoustic behavior and communication of bark beetles was previously unstudied by entomologists, and now he’s being called to consult with scientists studying not only the piñon pine beetle, but also the mountain pine beetles ravaging larger higher-elevation and higher-latitude pines, as well as insect pests of the non-beetle persuasion.

This past week, a long article appeared in several Canadian newspapers, providing the most detailed look yet at David’s beetle odyssey.  It’s an excerpt from a new book by Andrew Nikiforuk, Empire of the Beetle: How Human Folly and a Tiny Bug Are Killing North America’s Great Forests.  The article dubs David “the tree whisperer,” though so far he hasn’t quite figured out how to calm the outbreaks; in fact, the research so far seems to be leading more toward driving beetles crazy than calming them.  But after forgiving the headline writer, we can sink into he article itself, which is the most detailed, entertaining version yet of David’s beetle adventures.

Ontario is definitely at the heart of current controversies over wind farm siting.  While an environmental tribunal ruled against a health-based appeal in July, allowing the 8-turbine Kent Breeze Wind Farm to continue operating, many of the same issues will soon be argued in court.  A local family that lives just over 1.1km (just under three quarters of a mile) from the nearest Kent Breeze turbine has filed suit against three companies behind the project, saying that since the wind farm went operational in May, they’ve suffered from vertigo, nausea, and sleep disruption, and more to the point, that the developers knew this could happen.

“Within two weeks of them starting up I was in the emergency. I was dizzy and unable to stand. I was given medication and it has been four months and it hasn’t gotten better. I get motion sickness and light headed,” said Lisa Michaud. “At night I’m afraid to lie down because of the constant vibration and spinning.”

At the heart of the court case is the claim that the possibility of health impacts is known to exist, and indeed, parts of the report from the tribunal appeal which lost last month are called on to affirm this:

“This case has successfully shown that the debate should not be simplified to one about whether wind turbines can cause harm to humans,” the Environmental Review Tribunal stated in a report on the Kent Breeze project. “The evidence presented to the tribunal demonstrates they can, if facilities are placed too close to residents.”

In essence the Tribunal ruled that existing Provincial siting rules are sufficient to meet the threshold it imposed; these rules call for at least a 550m setback from homes, about half of what the family filing suit is living with. As reported in detail on AEInews at the time, the Tribunal report is a fascinating overview of the current state of the wind farm noise issue, with long summaries of expert testimony from both sides. The tribunal, while affirming the value of ongoing research into health effects and the nature of wind farm noise, ruled that the more cautionary evidence remained “exploratory,” rather than “conclusive,” and set a threshold for ruling that would require that the wind farm “will” cause “serious harm.”  Short of that, the Tribunal ruled that it could proceed. It seems likely that the court will be asked to review much of the same conflicting testimony; I am not sure whether the legal thresholds are different there than in the Tribunal process.

Meanwhile, the wind boom in Ontario has become a key issue in the current provincial election campaign, with both the candidates taking opposite stands and citizens speaking against current siting standards province-wide. Since the current Liberal government sponsored the Green Energy Act and its current standards, much of the opposition takes a decidedly conservative edge, often including opposition to government support for renewable energy in general and wind energy in particular. It certainly goes far beyond noise concerns for many of the most vocal opponents, with health impacts joining more generally conservative principles in arguments being made. One woman who has had to move from her home recently told a rally that the Liberal government is “denying” the health impacts of turbines and “ignoring” the people who are suffering. “People just aren’t going to sit back and take it anymore…We’re going to have your government so low, so low, so low, you’re not going to get elected. It’s as simple as that.”

Meanwhile, Liberal candidates including current leader Dalton McGuinty note that the standards are among the world’s most precautionary, and refer to a 2010 provincial report that focused on direct health impacts: “I rely on our chief medical officer of health here in Ontario to tell us what’s safe for our families,” McGuinty said Thursday. “What we have heard, of course, is doctors [and] nurses for 20 years now, they’re saying you got to shut down coal-fired generation in Ontario.”

The Maine Board of Environmental Protection has approved new wind farm noise standards that will lower night time noise limits to 42dB at the property line of any nearby homesites, a 3dB reduction from the old standard.  The daytime limit of 55dB remains unchanged.  Community groups, which initiated the review with a formal citizens proposal, had encouraged a standard of 35dB. The new rules will need to be approved by the state legislature in January.

Read new rules in full. (note: first half includes markup edits; second half is final version)

The new rules also include detailed procedures for measuring noise and establishing compliance with the noise limits. In the fine print, there is one provision that appears to add noise protection for neighbors, and some that raise questions.  The additional protections include a 5dB penalty if there is moderate blade swich (amplitude modulation) present; any repetitive pulse of sound of 5dB or more will trigger this penalty, meaning the average sound will then need to be 50dB during the day and 37dB at night.

The criteria for establishing compliance raise some questions. Read the rest of this entry »

The State of Victoria (Australia) has enacted new wind farm siting guidelines that prohibit construction within 2km (1.25 miles) of a home unless the owner has signed off on the nearby turbine(s). In addition, the new guidelines prohibit wind farms within 5km of many existing villages, in order to allow for future growth.  And, several areas with “a high degree of amenity, environmental value, or are a significant tourist destination” are excluded from development. (In Australia and New Zealand, the term “amenity” is often a factor in planning decisions; it largely corresponds to what we might also term rural quality of life.)

The new guidelines set a 40dB noise limit, reduced to 35dB in areas of “high amenity.”  It may be of interest to note that the Victoria planning authorities seem to equate 35dB to about a 2km setback, whereas an Oregon noise standard of 36dB has more often led to roughly half-mile, or 1km, setbacks.  It appears that the noise modeling is using different parameters in Oregon than in Victoria.  It’s also possible that the 2km buffer is designed to protect “visual amenity,” with the noise limit being a secondary feature of the guidelines.

Already, some wind farm developers have cancelled plans to build in Victoria, while locals who have experienced quality of life or health impacts praise the moves. I was especially struck by the reports of Adrian and Helen Lyons, who have 15 turbines within about 3km of their home, with the closest about 1.7km (just over a mile) away; both have reported a feeling of sustained pressure in their ears when the wind comes from the north.  The ear pressure has disturbed their sleep.  This spurs my ongoing question as to whether some of the physical sensations may have more to do with air pressure downwind of turbines, rather than noise levels.  To my knowledge, factors creating pressure differentials have not been investigated, although the related investigation of turbulence effects is on the research agenda of agencies and companies seeking to optimize turbine layout in wind farms.

See this site to download the new Victoria wind planning guidelines.  Or, see this Advisory Note summarizing the new amendments, and this PDF of the full planning and policy guidelines.

The Willow Creek Wind Farm has been given a reprieve from needing to address noise violations, as the Morrow County Court (the local name for county commission) decided not to enforce the state noise law.  Oregon has some of the most stringent noise standards, 10dB over night time ambient, which amounts to a noise limit of 36dB; the commissioners decided that the noise violations were minor and rare enough that they would not enforce them, a decision that was largely spurred by the fact that the state has abandoned its noise control enforcement efforts in 1991, leaving enforcement of the state standard to local authorities.

As covered previously on AEInews, dueling sound studies presented very different pictures of the noise violations.  An Invenergy study showed rare violations, but did not study sound at high wind speeds; a sound study by local residents showed excess noise especially at high wind speeds, with one home experiencing noise over 40db on the majority of nights.

“I’m flabbergasted,” said Jim McCandlish, a lawyer for three of the neighbors, after the vote. “The county court has an obligation to protect the health and welfare of its citizens.” McCandlish said his clients’ constitutional right to due process was being denied, and said the neighbors intend to appeal the decision to Oregon Land Use Board of Appeals.

The County’s actions were in part a response to a ruling by LUBA in June that questioned the county’s interpretation of the 36dB noise limit. In its ruling, LUBA sided with the wind developer, which had said that the state laws allow wind farms to produce up to 10dB more than ambient sound levels; the county had been suggesting that if the developer doesn’t conduct ambient noise studies before construction, they must assume ambient of 26dB.  The LUBA decision said that this requirement to choose whether or not to do an ambient study prior to construction did not appear in the state rules, leaving room for companies to show later that measurements of turbine noise levels exceeding 36dB were  made when the ambient was above 26dB.

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.

Read the rest of this entry »

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,

Read the rest of this entry »

A really fascinating multi-year study is underway at the Kenai National Wildlife Refuge which sits on a peninsula along the south side of the Cook Inlet in Alaska (Anchorage and Wasilla are at the innermost tip of Cook Inlet).  Tim Mullet, a Ph.D. student at what looks like an amazing program at the Institute of Arctic Biology, is undertaking what may well be the most comprehensive soundscape analysis ever undertaken on a landscape scale. “As far as I know, nobody has attempted to model sound in the landscape,” says Mullet. “We could encounter some big surprises there.”

Over several summers and winters, he is collecting recordings with 13 units placed in different areas of the refuge; some are permanent locations, and others he moves around in order to explore the soundscape in more areas. He already has 85,000 hours of sound data, and hopes to expand his recorder array to 23 units this year as well. These two articles provide a great overview of what Tim’s up to.

Snowmobile density in the Kenai NWR (red most, blue least); note that the shaded areas on the east side are nominally closed to snowmobile traffic, yet show some sign of activity.

“At this point, I’ve got an idea that 30 to 40 percent of Kenai’s wilderness could be affected by human–made noise,” says Mullet. The study goes beyond simple decibels (loudness), though. It is a foray into the emergent field of soundscape ecology, which examines the interplay of anthrophony (human–induced sounds) and biophony (natural sounds).

Loudness is “a piece of this study,” says Morton, “but another piece is the origin of sound—whether it’s human or nature—and developing a ratio between the two. It’s definitely cutting edge.” Understanding the relationship between anthrophony and biophony is important to the refuge and wildlife conservation in general, Morton says, because “human–generated noise can drown out natural noises—and that can be a huge deal, to the point where animals can’t actually hear themselves.”

In addition to collecting and mapping sounds, Mullet is studying whether moose who live closer to high levels of sound show higher stress levels than those in more sonically pristine areas.  While some snowmobiling advocates seem concerned that Mullet’s work may lead to new restrictions on their access to the refuge, Mullet himself understands and appreciates the key role of snowmobiles in Alaskan recreation, and aims to simply clarify what the various cumulative impacts of noise may be. Snowmobile trails create other impacts as well, especially compacting snow, which can benefit wildlife by offering travel paths, though biologists are also interested in how this easier travel may shift some predator/prey relationships.

More info: See two articles written by Mullet, one on the many qualities of snow, and the other exploring our different ways of listening, and introducing the Kenai study.  Also of interest from Tim is this research proposal, which summarizes previous research into both the impacts of noise and other snowmobile impacts (unfortunately, the sections of the proposal that are yellow-highlighted come through on the pdf as blocked out).

A Japanese research effort that’s been around for a while has gotten a blast of media fame this week, claiming the potential to triple power generation by using a ring around the blade-swept disc that focuses wind past the blades, as well as, I think, capturing some of the energy off the blade tips.  Sounds great in a headline, but as with most new turbine design “breakthroughs,” this one is early in R&D: the field trial models are only 5kw, with two 100kw, 13m-diameter, models recently erected. Whether the design can scale up, or be constructed economically in large arrays of smaller units, remains to be seen.  The weight of the ring has to be a challenging design feature when it comes to actually building large versions of this in the real world. Nearly every efficiency-improvement approach also touts a reduction in noise output as one of the benefits.

The best coverage of the “Wind Lens” research appeared on Clean Technica; they included these links to the lab’s research page and a conference poster. For good measure, here’s a couple other new approaches to increasing turbine efficiency previously covered in Clean Technica, with equally uncertain futures.  More power to all these researchers, whether in university labs or backyards.  Just don’t assume that a catchy headline means the revolution is neigh.  (Being a dreamer, I remain quite fond of ongoing research in California that seeks to harness extra energy by mimicking fish schooling patterns with small vertical-axis turbines, as covered previously here.)

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.

A group of 17 teens with mixed hearing ability (most with significant hearing loss) recently took a five-day river trip down the Grand Canyon as part of a program entitled Hear the World Sound Academy: Amplifying the Grand Canyon.  The Sound Academy students traveled with Bill Barkeley, a world-class mountain climber and one of the 15,000 people in the United States with Type 2 Usher’s Syndrome – the leading cause of deaf-blindness in the world. Bill’s 2007 summit of Mount Kilimanjaro shattered expectations and confirmed his role as an advocate and inspiration for the hearing loss community.

A fantastic blog charts the preparations, adventures, and post-trip reflections of the teens and their guides along the way, including staff from the National Park Service Natural Sounds Program.

The German Federal Agency for Nature Conservation (BfN) is working with a consortium of offshore wind companies to find ways to reduce the noise created during construction of wind farms.  An article in Der Spiegel is a good introduction to the efforts:

“From the standpoint of environmental protection, it’s necessary to decrease noise pollution in marine ecosystems,” BfN acknowledges in the introduction of its recent report. The study looks to the guidelines set forth by the Federal Environment Agency (UBA), which suggest that noise outside of a 750 meter radius from the construction site should not exceed 160 decibels. Techniques like bubble curtains, according to the BfN report, can meet this standard.However Greenpeace takes issue with this value because it is based on single-sound exposure — and it takes much more than a single punch into the bed rock of the sea floor to install a wind turbine foundation.

Eight companies are working together to investigate noise-reduction techniques; this article summarizes their goals.  This “Permanent Joint Working Group” is co-hosting a conference in September along with German federal agencies; here’s a brief intro, and here’s the conference website (good luck with your online translation service!)

Here’s a great fifteen-minute radio feature from Voice of America that digs into the issue of shipping noise and its effects on ocean life.  It features Michael Jasny of NRDC, recordings of shipping noise off Vancouver Island, NOAA’s Michael Bahtiarian on their quiet research ships, and Kathy Metcalf of the Chamber of Shipping of America.

Give a listen!

(transcript also included at that page link)

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.

A drilling rig is up and running in Cook Inlet, along the southern Alaska coast.  The rig, which will remain in the Inlet for 8 or more years, drilling numerous wells during the short summer seasons, expects to complete this first oil and gas well by the end of October, well before ice develops.  Local environmental groups pressed the Army Corps of Engineers and NOAA to not allow the rig into the inlet, citing concerns that oil and gas development activity will negatively impact a recently-designated 3000-square mile critical habitat for the critically endangered local beluga whale population.  In addition to possible impacts of a spill, noise from drilling in a central concern.  The permits allowing drilling require the company to maintain beluga observation crews, and to reduce the speed (and thus noise) of the drill when belugas are nearby, and shut down operations if they come very close.

Cook Inlet is over a hundred miles long, with Anchorage at its inner end; this is also the section of the Inlet that is now designated as critical habitat.  The first drilling operation is in the central part of the critical habitat, between Kenai and Tyonek on the map below.For more on the situation, see the two links above, which go to fairly detailed articles in the local media, and see these two previous AEI posts about the Cook Inlet belugas.

Wind development in the promising borderlands region along the Scottish/English border has come to a standstill, due to very low intensity ground vibrations interfering with a key nuclear test ban monitoring station in Eskdalemur, Scotland.  The Ministry of Defence has been tracking the increasing seismic interference from wind farms in the region, and says that any more would push the wind turbine vibrations  to the point that their seismic monitoring array would no longer be able to reliably hear distant seismic anomalies.

According to an article in The Guardian, “the swishing blades of wind turbines cause vibrations in the ground that can be detected by the sophisticated monitoring equipment at Eskdalemuir. An expert study for the MoD concluded that although the station could cope with some seismic noise, increasing this beyond a certain level would be unacceptable. The limit has now been reached so the ministry is objecting to every new wind turbine within 50km of Eskdalemuir.”

An earlier 80km exclusion zone has been a flexible one, with a period during which the MoD only excluded wind development as close at 10km from the installation, with several wind farms built in the 50km zone (orange circle at right).  At this point, however, the MoD feels they have reached the limit of acceptable infrasonic interference.

One wind power company, REG, which recently had a planned development rejected due to MoD objections, reports that efforts are underway to find a technological fix that could reduce the subtle vibrations that are causing the issues. One idea is to hang weights like pendulums inside turbine towers to deaden the vibrations from the blades. The MoD promised it would reassess its opposition if there were a proven technological solution.

It must be stressed that the vibrations being discussed here are extremely small, far below what would be felt in a home.  We’re talking about a sensitivity that can pick up small seismic anomalies from around the world.  Nonetheless, even though the MoD’s concerns at 10-50km are about impacts far below thresholds that neighbors would notice, I do wonder whether dampening technology developed to address MoD concerns would also reduce some of the more localized vibrations.

We need to keep clear the distinction between pure vibration, transferred through the towers into the ground, and the infrasonic elements of the sound from wind off the blades; it’s unclear that the proposed pedulum-inside solution would affect the in-air infrasonics. For that matter, the press reports are fairly vague about the source of the troubling seismic interference, with that reference above to it being related to wind off the blades, which would, indeed, imply that the strong infrasonic component of wind turbine sound is the source of the problem.  Still, the MoD’s concerns about effects at 10km or 50km should not be taken to mean homes in these ranges are at risk.  However, this does make me wonder whether any other industrial developments (factories, especially) that produce strong infrasonic sound are an issue at distances as far as 50km; if not, it may offer an example of how wind turbines are a relatively unique acoustic presence in the landscape.

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 »

For the second of a planned five summers, a team of researchers is spending a couple weeks in waters off southern California, attaching suction-cup acoustic tags to whales, then playing sounds underwater to see how they respond to different sounds and intensities. Another two weeks of field work will occur in late September. As Brandon Southall notes on his SEAblog, which provides excellent coverage of the trip, the team is “interested in testing the differences in responses of marine mammals in the various kinds of habitats in which they live and are exposed to human sounds.” After several years of study, the research is moving beyond simply getting one or two examples of any given species, toward the development of a wide array of examples of each species, in different circumstances (at least for the easier-to-tag species). The study is known as a Behavioral Response Study (BRS), which used to be called Controlled Exposure Experiments (CEE), with the CEE term still in use as the name of each individual playback to a tagged animal. This year’s southern California version goes by the name of SOCAL-11. The acoustic tags used in the study allow researchers to record the actual sounds heard by the animals (including of course their own foraging and communication vocalizations), while also tracking their swimming speed and dive patterns.

It’s always easier to find and approach the large whales, such as blue and fin whales, so the team tends to focus on these species when waves are higher; in light seas, they are largely seeking the harder-to-locate, and much harder to approach beaked whales, as well as Risso’s dolphins. Here’s a taste of what you’ll find if you follow the study on the SEAblog (the picture above is the animal he’s so enthused about):

Rissos dolphins are among our focal species for SOCAL-11 experiments.  We conducted one CEE on this species last year in SOCAL-10 and have been hoping for more this year.  This species has also proven somewhat difficult to tag in the past and our tags on last year were for just a few hours, so to get a nine hour deployment spanning several different behavioral modes was pretty exciting.  The tag came off late into the evening, but quite close to our anchorage and we made a beautiful late night ride in very calm seas and a red-yellow moon out to safely retrieve it.

In addition to increasing the data set of carefully measured behavioral responses to sound, the researchers are testing two leading-edge technologies: a next-generation acoustic tag, and a towed hydrophone system deployed from a sailboat that’s being used to try to find animals for possible tagging by hearing them from afar.  Plus, associated research is underway, including a study of the prey and oceanographic conditions around tagged animals, which aims to learn something about how the ocean conditions relate to where the prey is, and thus where the whales are, as well as to see whether behavior in response to sound is different when prey is present or not.

You can learn more about the SOCAL BRS study, including powerpoints describing last year’s findings, at the SOCAL-BRS web page.  Or, get more current updates by following the study on the SEAblog, or on the SOCAL-11 Facebook page (which includes some videos):

http://www.facebook.com/home.php#!/pages/Behavioral-Response-Studies-of-Marine-Mammals/153316228012219

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,

Read the rest of this entry »

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.