Resource Library Category: Ontario (55 items)
Documents presented here are not the product of nor are they necessarily endorsed by National Wind Watch. This resource library is provided to assist anyone wishing to research the issue of industrial wind power and the impacts of its development. The information should be evaluated by each reader to come to their own conclusions about the many areas of debate.
Response to HGC Literature Review
Source: Harrison, John
Response to “Low Frequency Noise and Infrasound Associated with Wind Turbine Generator Systems – A Literature Review”
Also see: “Compliance Protocol for Wind Turbine Noise – Guideline for Acoustic Assessment and Measurement”
Introduction
The low frequency report, prepared by Howe Gastmeier Chapnik Ltd. was commissioned by the Ministry of the Environment (MOE), released in draft form in August 2010, released in final form to MOE in December 2010 and to the public in August 2011. Why MOE is issuing it now as a press release is a mystery. This response will address the report itself and the news release from the Ministry of the Environment.
A glaring omission from the report and the news release is the motivation for the commission to HGC. The motivation of course is that a large number of residents living in proximity to wind turbines are suffering from annoyance, sleep deprivation and resulting adverse health effects. The root cause of the annoyance is the noise generated by wind turbines.
Not only does the report and news release avoid mention of the motivation for the commission, neither MOE, the Ontario Chief Medical Officer of Health nor HGC made any attempt to interview those suffering from adverse health effects
The commission focused on low frequency audible sound and infrasound because at a distance of several hundred metres from a turbine much of the high frequency sound has been absorbed by the atmosphere.
The annoyance associated with turbine noise is considerably larger than noise of a similar sound pressure level generated by traffic or industrial noise. For instance field studies by Pedersen, van den Berg, Bakker and Bouma (referenced in the report) show 15% and 27% of a population are annoyed by sound pressure levels in the ranges 35 to 40 dBA and 40 to 45 dBA respectively. [Pedersen et al. consider five reactions to turbine noise: do not notice; notice but not annoyed; slightly annoyed; rather annoyed; and very annoyed. They group rather and very annoyed together under the heading “annoyed”.] These numbers are to be compared to 3% of a population annoyed by traffic noise in the same sound pressure level range. The present Ontario noise limit is 40 dBA; the noise limit before the Green Energy Act was 51 dBA in a sufficiently high wind. As noted below the Ontario noise limit is based upon prediction with significant noise contributions to the prediction not considered.
Possible reasons for the difference in response to turbine noise and road or industrial noise is the predominance of low frequencies in the turbine noise and the characteristic amplitude modulation of turbine noise at the blade passage frequency; this amplitude modulation draws continual attention to the turbine noise in the way that a dripping tap does. The wind industry and its lobbyists make much of the contribution of attitude to wind turbines to the annoyance. However, it is difficult to think that the attitude to industrial plants or road noise would be any less benign. In addition, while Pedersen et al. show a linear dependence of annoyance on the turbine sound pressure level there is no similar study showing a linear dependence of annoyance on attitude!
Not for nothing do the following health and other experts propose setbacks well beyond those allowed by the Ontario Ministry of the Environment:
The HGC report gives considerable prominence to the Colby et al. health study and to the Chief Medical Officer of Health, Dr. Arlene King, health study. The one was commissioned by the Canadian/American Wind Energy Authorities and the other by the Ontario Government which is far from unbiased with respect to wind energy. Both are seriously flawed, notably in having no interest in the numerous people suffering from adverse health effect and in emphasizing the absence of direct health effects. Generally the adverse health effects are indirect: sleeplessness and annoyance leading to stress-related illnesses. This is recognized by the World Health Authority which considers annoyance and stress as adverse health effects. A recent paper by Dr. Carl Phillips, a noted epidemiologist, offers a detailed critique. The King report is marred by an erroneous quotation from the 2009 Pederson et al. paper of the number of people annoyed by turbine noise. Dr. King has yet to acknowledge this error/deception.
Technical Review
As must be, much of the HGC report concerns technical aspects of noise generation and sound propagation. Here there is a fairly complete literature review. However, this section fails to emphasize that the turbine manufacturers are aware that the future of widespread acceptance of wind energy will depend upon reducing noise and low-frequency noise. To quote:
“The acoustic noise radiating from wind turbines continues to be the dominant design driver that must be incorporated into the design process. The tip speed of many turbine designs is limited by the amount of noise created by the blades passing through the atmosphere.” Moriarty (NREL, USA) et al., AIAA Conference Proceedings (2005).
“… noise emission … has become one of the most important environmental impacts of wind energy.” (Romero-Sanz and Matesanz (Gamesa Spain), Wind Engineering, 32, 27-44 (2008))
As stated in the report a major cause of turbine noise is aerodynamic trailing-edge vortex creation. There has been theoretical and wind-tunnel research to investigate the effect of different blade cross-sections on TE noise.
Perhaps of far more importance for low frequency and infrasound noise is the work on inflow turbulence. HGC, the Ministry of the Environment and CanWEA continue to bury their heads in the sand concerning this issue. This important noise source has been brought to the attention of MOE and the Canadian acoustics community by bringing to light the early work at the National Renewable Energy Laboratory (NREL) in the USA. This work demonstrated through theoretical work based upon the mathematical modelling by Amiet and through experimental work with the NREL CART up-wind test turbine that turbulent inflow considerably enhances the low frequency noise emitted by turbines. More recently, Dr. Moriarty has brought to my attention their continuing work, in collaboration with Dr. Guidati, well-known as a co-author of the Wagner et al. treatise on wind turbine noise.
On July 8th, 2011, The National Laboratory for Sustainable Energy, Risø, Denmark placed the following description in an advertisement for a scholarship: “Noise is an interesting concern for wind turbine manufacturers and communities living near wind turbines. These concerns are exacerbated by the constant increase of wind turbine sizes and the cost advantages of placing turbines close to the consumers. The design of low-noise turbines requires the use of validated and accurate engineering models. The main sources of noise generated by a wind turbine have been identified as turbulent inflow noise and trailing edge noise”
If still not convinced then Figure 32 of a recent report by K.D. Madsen and T.H. Pedersen should be enough (“Low Frequency Noise from Large Wind Turbines” DELTA report AV-1272/10 (2010)).
Other work not referenced concerns measurement of turbulence intensity. This work is being done because turbulence increases dramatically low frequency noise, because it puts stress on the turbine blades and because, with associated wake loss, it decreases the capacity factor of downwind turbines. A list of references that needed to be addressed is as follows:
Lange et al., “Modeling of Offshore Wind Turbine Wakes”, Wind Energy, 6, 87 (2003).
Barthelmie et al., “Modeling and measured Power Losses and Turbulence Intensity …”, Wind Energy, 10, 517 (2007).
Wagner et al., “Influence of Wind Speed Profile on Wind Turbine Performance Measurements”, Wind Energy, 12, 348, (2009).
Barthelmie et al., “Off-Shore Wind Turbine Wakes Measured by Sodar”, J. Atmos. Oceanic Tech., 20, 466 (2003).
Bertaglio, “NACA0015 Measurements in LM Wind Tunnel and Turbulence Generated Noise”, Risø National Laboratory for Sustainable Energy (2008) (report # Risø-R-1657(EN))
In Europe, the European Commission is supporting turbine research through the SIROCCA Project: http://www.ecn.nl/nl/units/wind/projecten/sirocco/
Propagation of Low Frequency Noise (Section 3.2)
The report makes important points concerning the propagation of turbine noise: The cylindrical decrease in sound energy, the acoustically hard character of ground for low frequency sound, the low absorption by the atmosphere for low frequency sound and the ready penetration through residence walls. These points needed to be emphasized in the executive summary, the conclusions and the recommendations. At present they are not acknowledged by the Ministry of the Environment. This is especially important as guidelines are drawn up for off-shore wind energy.
Noise Annoyance (Sections 3.5, 3.6 and 3.8)
Laboratory studies have their place. Nevertheless, for reasons that Dr. Leventhall gives, as referenced in section 3.6, far more weight needs to be given to field studies in comparison to laboratory studies. Missing from Section 3.6 is consideration of the amplitude modulation. This is typically 5 dBA but higher values have been reported. Dr. Leventhall himself has written: “A time-varying sound is more annoying than a steady sound of the same average level and this is accounted for by reducing the permitted level of wind turbine noise”. As we are well aware, the Ministry of the Environment refuses to do this.
Section 3.8 quotes the work of Pawlaczyk and Luszczynska. It was only fair to have quoted also the work of Persson Waye et al. (“Low Frequency Noise “Pollution” Interferes with Performance”, Noise Health, 4, 33, (2001)). This paper comes to the opposite conclusion for low frequency noise at the 40 dBA level.
Health Effects (Section 3.11)
The Colby et al. and King reports were dealt with above. Turning to the discussion of Dr. Pierpont’s work, the report is bizarre. There is no mention of the bulk of the work on the medical study of a large number of people suffering adverse health effects resulting from wind turbine noise. This work analyses the range of symptoms and finds reason to treat them collectively as a syndrome. Separately, there are hypotheses for the cause of the syndrome. Hypotheses are not proofs; scientifically, the presentation of a hypothesis is reason to study the problem and to demonstrate proof or otherwise. Whether the hypotheses are correct or not is irrelevant to the fact that there are adverse health effects. The energy devoted by Colby et al., King, CanWEA to denigrate the medical and diagnostic work of Dr. Pierpont is reminiscent of the methods we saw some decades ago used by the tobacco industry! Again, I recommend a reading of the Phillip’s report on the power of crossover analysis in understanding the reality of adverse health effects from wind turbine noise. There is a reference to Leventhall (2010) missing from the bibliography; nevertheless, I know that Drs. Leventhall, Colby and King are not epidemiologists!
Conclusions (section 5.0)
1) Although turbine noise is broadband, at a distance of 500 metres, much of the high frequency sound has been absorbed. Distance enhances the low frequency component as does turbulent inflow.
3) Reference needs to be made to the Salt study demonstrating other pathways for the perception of very low frequency sound.
4) This conclusion is wrong and is a red herring. Turbine noise in the range 35 to 45 dBA causes annoyance and sleep disturbance. These are adverse health effects and in turn lead on to other adverse health effects. 100 people reporting adverse health effects and more than a dozen families abandoning their homes in Ontario alone gives the lie to this conclusion.
5) Non-trivial (a derogatory and unworthy expression) has no place in a professional report. It should be replaced by about 20% being annoyed.
Recommendations (Section 6)
Given that the review of current technical literature in the HGC report has missed completely research dating back to Amiet and forward to detailed comparisons between theory and experiment on turbulent inflow noise, the first recommendation needs to be revised. MOE does need to revisit its guidelines to include turbulent inflow noise, to treat the ground parameter as hard for low frequency sound, to reconsider spherical spreading, particularly for off-shore sound propagation, to address the uncertainty in the prediction of sound at a residence and, given the accepted enhancement of annoyance due to amplitude modulated noise, to apply a penalty for amplitude modulation.
Response to Backgrounder: Low Frequency Sound and Infrasound Report
What kind of noise do wind turbines produce? Turbines do indeed produce a wide range of frequencies. However, the noise 550 metres or more from the turbine is skewed towards low frequency noise because of selective absorption of the high frequencies by the atmosphere.
Is wind turbine sound harmful? The Minister of the Environment writes that there is no direct health risk. However, field studies have demonstrated that 15 to 27% of people exposed to turbine noise at the Ontario regulated limit will suffer annoyance. This is an adverse health effect and in time leads on to other adverse health effects such as stress, tinnitus, headaches and sleep disturbance.
Are Ontario’s rules to control wind turbine sound stringent enough?
The minister writes that at the Ontario regulated setback much of the sound that turbines produce lays outside the range that people can hear. This is untrue. Field studies show that at the regulated setback, 80% of people can hear the turbine noise. Also, the minister fails to note that Germany, with its more extensive experience with wind energy, has a lower night-time noise limit than Ontario.
John Harrison, harrisjp/physics.queensu.ca
Collecting data on wind turbine sound to identify causes of identified concerns
Source: Palmer, William
Regulations for wind turbines are generally based on A-weighted sound levels, and typical sound spectrums in the community from a localized source. Regulatory limits are based on levels believed to cause little annoyance. Large industrial wind turbines are a sound emitter that present a spatially distributed source principally arising close to the blade tips, rotating 50 to 150 metres overhead so that sound arises from a wide area. They pose a relatively new source of sound to communities, particularly the quiet rural communities where they are mostly located. Community experience shows that the same A-weighted sound limits that are acceptable for typical sound spectrums and localized sources give rise to a considerable level of annoyance from wind turbines. This paper sets out to identify the differences in the sound found at locations considered acceptable by regulators 500-600 m from wind turbines (about one-third of a mile), in spectrum, intensity, duration, and special characteristics, such as tonality or amplitude modulation compared to the sound levels at control sites distant by at least 5000 m (about 3 miles) from wind turbines. An explanation of the data collection method is given, as well as an analysis of extensive sound samples gathered.
Published by the Acoustical Society of America through the American Institute of Physics
Learning from Evidence of Sound Experienced from Wind Turbines
Source: Palmer, William
1. INTRODUCTION
Wind turbine sound regulations are generally based on A-weighted sound levels, reducing the effect of frequencies outside 500-11,000 Hz by more than 3 dB. Wind turbine sound predominates at lower frequencies where human audibility and physiological response still exists. Regulatory limits are not intended to pose annoyance, yet placement of wind turbines near homes is reported to cause significant annoyance, sleep deprivation, and adverse effects.
Large industrial wind turbines produce a unique sound signature, cyclical in both amplitude and frequency, from a source that varies in a cyclical pattern of position and distance relative to listening points, since the principal sound source arises from turbulence following the trailing edge of the outer quarter of the blades, an annular ring 75 to 100 metres in diameter, a noticeable variation in relation to the 500 to 3000 metres from turbines to impacted receptors.
This paper relates factors identified previously by others to facts determined by recording and analyzing the differences in samples of sound over a full year at sites in a wind power development of 110 Vestas V82 turbines in Ontario’s Bruce County, located acceptably to provincial regulators for spacing from wind turbines, and at control sites in the same environment at greater distances from the turbines.
2. METHODS
This paper will identify key findings related to the subject of sound of wind turbines identified by others at the Fourth International Meeting on Wind Turbine Noise held in Rome, in April 2011, and the 161st Meeting of the American Acoustical Society, in Seattle, in May 2011. Then, this paper will outline how the research conducted in this study relates to the issues raised by others.
2.1 Key Findings from Recent Conferences
No rigorous epidemiological study has been conducted by any jurisdiction, which would be necessary to show a direct relationship between the sound produced by wind turbines and health effects, as was done to show the suspected but unproven link between smoking and health.
The need for research to show direct clinical evidence was identified by Greg Tocci [1], as the requirement for policy makers to move sound from annoyance, to a health effect. Tocci commented that this had resulted in a 30-year period of “benign neglect” of sound in the US, although he noted work in progress in Europe sponsored by the WHO with regard to “The burden of disease from environmental noise” at conferences in 2005, ’07, and ’11, chaired by Rohku Kim.
Papers presented have shown wind turbines do produce a distinctive sound [2,3]. Sound levels similar to those experienced by people living at approved setbacks from wind turbines has been shown to produce direct and adverse impacts on blood pressure (systolic and diastolic), on heart rate, and on respiration rate4. The link between wind turbine sound and sleep disruption was noted by researchers [5,6,7].
Further, the evidence from qualified sleep researchers [5,8,9] shows “annoyance” of sleep disruption from any cause can result in delayed sleep onset, recalled awakening (for periods of >30 seconds), and perhaps most importantly, in repetitive non-recalled arousals (for periods of <30 seconds). These, sleep researchers state, can have adverse impacts of fatigue, decreased performance, increased accident rates, cardio-vascular impacts, and diabetes.
Salt presented [10] a physiological link between the response of the ear to low frequency sound unrelated to audibility. Specifically, the response of the outer hair cells of the ear, and the response of the fluid in the inner ear to infrasound may be enhanced, and Salt stated it is premature to dismiss the influence of wind turbine noise on the ear. Literature identifies the link between the response of the fluid in the inner ear and motion sickness and disruption to balance.
A number of presenters discussed the psychoacoustic linkage between the “soundscape” and annoyance. George Luz presented a tutorial11 identifying that noise sensitivity (about 1 in 5 people) does not decrease over time, while it may increase. Luz concluded with a statement about airport siting, “it may be premature to infer that decision makers at the studied airport planned to cause harm to minority groups. Less invidiously, decision makers might try to please important constituents (such as the median voter), without thinking through the possibility that decisions to help median voters may cause harm to others.” The applicability to wind turbine siting was chilling.
A number of papers showed the consequence of not having a basis for noise standards when developing public policy. The conflict between potential community benefit (such as jobs) was often traded by municipal governments [11,12,13] against occasional “annoyance”, and there was great diversity between what was acceptable in one community versus another. This clearly identified that a government policy that gives total control of the siting of wind turbines to individual municipalities is inadequate to protect citizens.
Many speakers identified the necessity to listen to the noise sources to identify special characteristics they possess, not just to record level as the “quality” impacts annoyance. The conferences identified a number of ways in which the sound
from wind turbines is unique, and how the particular characteristic of the sound makes wind turbines more annoying. Richarz [14], presented on audible low-frequency wind turbine sound. He noted that auto-correlation of measured wind turbine sounds exhibits distinct, periodic “low frequency” pulses that when propagation effects are accounted for, result in an audible swoosh. McCabe [15] reported he had identified elevated levels of amplitude modulation with a diurnal pattern, more noticeable at night, which might be why wind turbines are more annoying than other sources. di Napoli [16] reported on very strong amplitude modulation from monitored turbines and that it is not possible to conclude that amplitude modulation decreases with distance, as do simple assessments. Lundmark [17] reported that it was not possible to compare wind turbine sound to beach noise or waterfalls, and explained why turbine sounds were disruptive, rather than calming.
2.2 The Method of the Current Research
Digitized sound samples were recorded at 6 nearby sites in the environment of a wind power development during all seasons of the year. The method is explained in detail and detailed results are presented in the reference [18].
3. RESULTS
This study showed that receptors at setbacks approved by Ontario regulators for wind turbines experienced sound levels 20 dB higher at all octaves up to 1000 Hz compared to a site in the same environment 5000 metres from the wind turbines any time the turbines were operating, even at very low power. The study also identified frequency and amplitude changes in the sound from wind turbines, which make them even more noticeable; much like the wee-woo of emergency vehicle sirens makes them noticeable. The work also showed that actual sound readings taken by the acoustical consultant of the proponent of a wind farm in response to a complaint identified that sound levels exceeded the predicted value fully half of the time at midnight, were 3 dB or higher above the predicted value at least 25% of the time at midnight, and were correlated to turbine power, not ambient wind speed.
4. DISCUSSION AND CONCLUSIONS
While “direct health effects” from the sound from wind turbines has not been shown by epidemiological study, clear links to adverse health effects from increases in sound level, roughness, etc. are shown, increasing blood pressure (systolic and diastolic), heart rate and respiratory rate.
The link between sound with special characteristics (e.g. cyclical amplitude and frequency modulation) and annoyance is known. The link between annoyance and sleep disturbance is known. The link between sleep disturbance and adverse health effects is well established. While some 1 in 5 people are more “noise sensitive” than others, no evidence suggests “attitude training” will erase this. The consequence of setting regulations without adequate basis, or using local regulation without protective guidance is clear. Evidence shows the low frequency dominance of wind turbine sound, and it’s human perception.
This paper has shown evidence that sound level at receptor locations approved in Ontario is some 20 dB higher at all octaves up to 1000 Hz compared to sites in the same environment distant from wind turbines. The increase in sound is shown to be due to the wind turbines, not ambient wind. Cyclical amplitude and frequency shift of the sound is shown to be related to the wind turbines.
Thus, the link between the sound from wind turbines, to annoyance, hence sleep disturbance, and hence to adverse health effects is established, but yet no epidemiological studies have been conducted to prove the direct health effect. Still, to ignore concerns identified and to continue to site wind turbines by current regulations would seem to be imprudent, if not negligent.
REFERENCES
Papers presented at 2011 Wind Turbine Noise Conference, Rome available at http://www.windturbinenoise2011.org/ (wtn 2011). Papers presented at the Acoustical Society of America 161st Meeting in Seattle are identified on the ASA website: http://acousticalsociety.org/meetings/past_meeting_program/seattle/seattle_program (asa 161).
1. Tocci, G, Sykes, D. Harmonizing national and worldwide acoustical guidelines for healthcare (asa 161)
2. Bowdler, D. Why Wind turbine noise annoys (wtn 2011)
3. Hunt, M. Assessment of Wind Turbine Noise Using NZ Standard NZS6808:2010 (wtn 2011)
4. Hsu TY, Ryherd E, Ackerman J, and Persson-Waye K. Psychoacoustic measurements and their relationship to patient physiology in an intensive care unit (asa 161)
5. Hanning C, Nissenbaum M. Selection of outcome measures in assessing sleep disturbance from wind turbine noise (wtn 2011)
6. van den Berg F. An overview of residential health effects in relation to wind turbine noise (wtn 2011)
7. Shepherd D. Wind turbine noise and health-related quality of life of nearby residents: a cross sectional study in NZ (wtn 2011)
8. Solet JM. In defense of sleep (asa 161)
9. Solet JM et al. Validating acoustic guidelines for HC facilities: the Sound Sleep Study, 2010 (Center for Health Design)
10. Salt A. Responses of the inner ear to infrasound (wtn 2011)
11. Schomer P. A community noise law for wind turbines (asa 161)
12. Park I. Environmental noise study and follow-up measurements at the White River Amphitheatre in Auburn, WA (asa 161)
13. Pettijohn SD. Locating a new outdoor performance venue amidst public concern and the resulting sound level impacts at the remote amphitheater site (asa 161)
14. Richarz W. Audible low frequency wind turbine sound (asa 161)
15. McCabe N. Detection and Quantification of Amplitude Modulation in Wind Turbine Noise (wtn 2011)
16. di Napoli C. Long Distance Amplitude Modulation (wtn 2011)
17. Lundmark G. Measurement of Swish Noise A New Method (wtn 2011)
18. Palmer W. Collecting data on wind turbine sound to identify causes of identified concerns (asa 161), available for download at http://asadl.org/poma/resource/1/pmarcw/v12/i1/p040003_s1?bypassSSO=1 (or enter http://asadl.org/search Palmer wind turbine) [or click here]
Download original document: “Learning from Evidence of Sound Experienced from Wind Turbines”
No Safe Place: McMurtry on industrial wind
Source: McMurtry, Robert
1. People all over the world are reporting adverse health effects caused by wind turbines.
2. The adverse health effects which they report are serious.
3. There are no evidence-based guidelines for safe setbacks of wind turbines from homes.
4. Research is required. Our preliminary work suggests a minimum of 2 kilometres (2000 metres, 6,652 feet). The average setback from people who are reporting these adverse health effects is 880 metres (2,887 feet).
Dr Robert McMurtry, Order of Canada, records his concerns about Industrial Find out about the effect of Wind Turbines on human health and community well-being, in this powerful video called “No Safe Place.” Dr McMurtry has devoted thousands of hours to learn about Victims of Wind across Ontario, and to share that knowledge with you. What is a safe “setback”? McMurtry says, “We don’t know.” Why is Ontario rushing to place even more turbines across the landscape when it is clear that people are becoming ill and even being forced from their homes? Internationally, thousands are reporting the effects, tinnitus, sleep disorders, stress, depression, vertigo, migraines, to name a few.
