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New AEI report: Wind Farm Noise, 2009 in Review

Effects of Noise on Wildlife, Human impacts, Science, Wind turbines Add comments

The latest in AEI’s ongoing series of comprehensive special reports on key topics is finally done!

This one is modeled on AEI’s acclaimed annual reviews of science and policy developments in ocean noise, but focuses for the first time on wind farm noise issues.  The 30-page report covers new research, public concerns, and industry trends over the past year.

Read the report in the embedded pdf reader below, or download a pdf copy.  Click on to below the fold for a table of contents and the report’s brief Introduction.

Contents

  1. Introduction
  2. Nature of the noise issues: Widely occurring noise and sleep disruptions
  3. Scope of the problem: Few wind farms generate complaints
  4. Noise limits: Useful targets, though hard to count on
  5. New research of note: Effects of wind farms on neighbors / Sound propagation, wind shear, acoustics issues / Effects on wildlife (10 pages, summarizing 22 papers and reports)
  6. Social considerations: Local social constraints and national social choices
  7. The Science/Experience Paradox: Reconciling the divide between reassuring research results and the life-changing impacts reported by some neighbors
  8. Looking Ahead: 2010 and beyond
  9. Resources

Introduction
During 2009, the Acoustic Ecology Institute has been tracking public concerns about wind farm noise, while also studying new research papers and industry trade journals and reports in order to get up to speed on this emerging controversy. AEI’s approach has been the same as we’ve taken to ocean noise issues since 2004: to do our best to cut through the rhetoric and hyperbole from advocates on both sides of the issue and get a clearer sense of the state of understanding of these noise impacts, in order to help inform emerging public policy choices.  With wind farm noise, as with ocean noise, the more we learn, the more obvious it is that there is much we still do not know.  And, it’s not nearly as simple as either side in this increasingly rancorous debate appears to think it is.
This AEI Special Report serves as an update and supplement to my initial work on this topic from late 2008, still available on our website at AcousticEcology.org/srwind.html.  While the focus of this report is to digest what we learned in 2009, it also will include some over-arching themes and bigger-picture context that I hope is useful as an introduction to those who are new to the consideration of the effects of wind farm noise on people living nearby.  Some of these themes have emerged over the course of this year as I’ve learned more, and have been introduced on AEI’s news and science feed at AEInews.org.

I invite you to be in touch with any comments, suggestions, or critiques of what you read here.  I also encourage you to read this report with an open mind and let your own understanding of these issues expand to include some new perspectives.  We’re all learning as we go!

  1. First, it is clear that many people, in all parts of the country, have been dramatically impacted by the noise of wind farms near their homes.  To dismiss all these people as cranks, or as hyper-sensitive social outliers, does a disservice to constructive public discourse, and short-circuits our opportunities to learn from their experiences as we continue to develop new wind farms.
  2. Second, it is also clear that wind farm noise is truly not that bothersome to most people who hear it or live near it, and that the vast majority of wind farms never generate any substantial ongoing noise issues.  Concerns that dominate public discourse and activist web sites can seem to accentuate the hardest to quantify issues (such as direct health effects, especially of low-frequency noise), while magnifying the extent of problems as communities consider new wind developments.
  3. Third, the nature of the sounds made by wind turbines make it especially difficult to rely on reassuring “noise limits” as proposed by states, counties, or townships. Several factors contribute to this dilemma. Noise propagation varies greatly with changing wind and atmospheric conditions; there are many different ways to average noise recordings, some of which can lead to noise levels much higher than local officials may think they are allowing; the pulsing nature of turbine noise is inherently more attention-grabbing and more easily disruptive than road or industrial noises; and finally, there is much we have yet to learn about the factors that create the most troublesome turbine noises, including pulses and low-frequency sound.
  4. And fourth, and perhaps most important yet least appreciated: we are facing some social choices that may be difficult to make.  While broad-brush studies report no simple cause-effect between wind farm noise and various measures of impact (health, annoyance, property values), it is also clear that a minority of those nearby do often experience dramatic, negative impacts.  How many such affected neighbors are we willing to accept?  5%? 20%?  We can no longer pretend this more affected minority doesn’t exist; it’s time to choose how much to adapt wind farm planning — or operations — in response to these impacts.

Jim Cummings, Executive Director, Acoustic Ecology Institute

    "Quick version" of AEI's 2009 wind farm report, courtesy of http://Wordle.net

    "Quick version" of AEI's 2009 wind farm report, courtesy of http://Wordle.net

The key messages of this report can be boiled down to four themes.

8 Responses to “New AEI report: Wind Farm Noise, 2009 in Review”

  1. Bill Palmer Says:

    Thank you for an excellent report. It raises many good points and presents a good view of trying to understand the issue. Some points are touched on and will need more expansion – for example the impact of cyclical noise is touched on (amplitude modulation) and will deserve more study.

    Also, the low frequency aspect is worth of note to make comparisons useful – a few only examples … 500 metres (1/4 mile) from a wind turbine one measures some 40 dBA and a cyclical 58 to 65 dBC. A refrigerator at 3 metres (10 feet) measures about 40 dBA and a steady 45 dBC. A noisy conference room with lots of air conditioning noise measures 45 dBA and a steady 58 dBC. A vacuum cleaner at 3 metres measures 65 dBA and a steady 69 dBC.

    What we find is that at the home impacted by a wind turbine, while the A weighted sound level sound like a refrigerator, the unmonitored cyclical low frequency noise varying between the noisy conference room and the vacuum cleaner.

    Like Mr. Cummings I have spoken to a significant number of people who are significantly impacted by wind turbine noise, and the dismissal of them by regulators who say “they will get used to it” is distressing.

  2. Kathy Russell Says:

    Finally, an Acoustic group looking at this issue with a common sense approach.

    To build on what Mr Palmer and Mr Cummings say, I too have spoken with a significant number of people who are impacted by wind turbine noise in Australia. What is also clear and does not appear to be mentioned is that those people who do experience noise compared with those who don’t at the same wind farm sites are not necessarily hearing the same things. The science of understanding why is young – but the contributing factors include different topographical, atmospheric and turbine proximity and turbulence characteristics also known as “hotspots” which will render one residence more susceptible to a particular noise characteristic than another.

    Add to this the different physical pre-dispositions of those inhabiting that particular dwelling (like migrane disorder, motion sickness, previous ear surgery, ear sensitivity, high blood pressure etc) and the issue escalates to a public safety issue.

    And why should an assessment of any percentage of affected community be considered an acceptable outcome in this debate and what is the method proposed to achieve this? With the rapid deployment of large numbers of turbines in close proximity to homes, particularly in Australia there are guaranteed to be many more affected communities displaced from their homes. Any simple risk analysis would identify this fact.

    Surely in this day and age we have the scientific skill and resources to investigate, find out the reasons why and rectify.

    In the mean time, the precautionary should prevail. Turbines should not be constructed near houses. At present we have a Government who refuses to acknowledge there is any issue. There is no hope for people genuinely affected. We need the Acoustic, Medical and Scientific community to step up and investigate the science using the real people who are suffering.

  3. aeinews Says:

    I have only had the chance to visit a couple of wind farms, but I have also heard that when you are in a home with severe noise issues occurring, it is often possible to walk a few hundred feet and find the noise much less intense, sometimes toward the turbines. So I suspect that Kathy’s point about hot spots deserves more attention.

    Of course, the forces that create such confluences of factors may well be so chaotic that it may well be nearly impossible to predict or even effectively investigate them.

  4. Kathy Russell Says:

    Re “Hot spots” – yes I have heard others describe the same phenomenom of louder noise inside versus less noise towards the turbines.

    At present the factors which are causing this situation are not fully understood or even completely identified and therefore cannot be predicted. And yes, there is a chance that some will never be identified, even given the passage of time.

    The only safe way to deal with this uncertainty is to incorporate setbacks into the planning process rather than playing Russian Roulette with innocent peoples lives.

    Not meaning to criticise the AEI, but at what point do other Acoustic associations throughout the world acknowledge that they don’t understand the science? Acoustic organisations in particular do not have the qualifications to investigate this science on their own (Engineers, Meteorologists and Medical research practitioners are just some of the other experts which come to mind). In spite of the Wind Industry’s assurances that there are no problems, experience indicates that the unknowns are so significant that they have no business making these assurances. The Wind Industry backs up these claims using the Acoustic Industry. Why doesn’t the greater Acoustic industry stand up and acknowledge that this issue exists and is impossible to predict as you have so correctly pointed out above.

    I deal with so many people in poor health and distress as a result of this widespread refusal to acknowledge a very real problem. I applaud your efforts to explore this subject further. But I think you have quite possibly identified the answer already…”impossible to predict or even effectively investigate”, therefore remedy the situation by not building them near homes.

  5. Bert Seeliger Says:

    Great report – Thanks.
    For over a year we have been trying to convince the wind farm developer and the government authorities of our personal situation regarding wind farm noise (sound pressure/vibration) without success. Four of these turbines are located in a semi circle within 1 km around our property, which is located in a soup bowl like terrain. And, yes, depending on wind direction and wind speed, the impact of the cyclical noise can be extreme. Believe me, I have tried to “get used to it”- alas, it doesn’t work.

  6. S. Johnston Says:

    As one of the residents within the one km radius described by Mr. Seeliger, I must concur. Turbine Town is not a pleasant place to be when the winds blow particularly from WNW clockwise —> ENE.

    Many thanks to Bill Palmer for his keen insight and accurate description of our situation after his visit to our homes.

    Thanks, too, to Kathy Russell for advocating on our behalf albeit from afar.

  7. Barry Bridgeford Says:

    I have examined the nature of the ‘wavelengths’ involved, along with their effects on both structures and people. For details, please refer to .. http://www.algonquinadventures.com/waywardwind/index.htm

  8. When is Wind Energy Noise Pollution? Says:

    […] year, the Acoustic Ecology Institute put out a report looking at the scattered nature of the […]

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