Friday, November 22, 2013

Questions and Answers: What's wrong with wind energy?

1. The National Wind Watch home page says, “because of the wind’s low density, intermittency, and high variability, [large-scale wind turbines] do next to nothing for reducing carbon and other emissions or dependence on other fuels”. Could you go into a bit more detail about this and present any links you have for evidence?

The power of the wind is 1/2 of area (turbine rotor diameter) × air density × wind speed cubed. There is a theoretical physical limit (Betz’ law) that no more than 16/27, or 59.3%, of the wind’s energy (power × time) can be captured. Modern wind turbines may reach 50% efficiency, but only within a certain range of wind speeds, which appear to be the average speeds for which the turbines are designed, but at which speeds they generate at only a fraction (around 1/3) of their maximum rate. As the wind speed increases, the rotors are increasingly feathered and efficiency plummets.

The brochure for Enercon turbines includes graphs showing the efficiency vs. wind speed.

In addition to being limited by Betz’ law, wind turbines must not interfere with each other, so they must be spaced quite far apart. The minimum distance is generally considered to be 3 rotor diameters perpendicular to the wind (possible only where wind is unidirectional) and 10 rotor diameters parallel to the wind. See, eg, Thus in an array of, say, 90-meter-diameter turbines (the blades of each machine sweeping a vertical airspace of 1.57 acres), each machine would require 810,000 square meters around it, or 200 acres. From that 200 acres, assuming a 2-MW turbine and an average rate of generation 25% of capacity (see for U.S. averages; they are generally quite a bit less in Europe), the average power density is only 2.5 kW/acre.

Furthermore, that wind energy is intermittent, meaning other sources of electricity must be available, and variable, meaning other sources must be kept running to be ramped up and down as needed to keep the electricity supply exactly matched to demand. This means that wind is only adding to the grid and then causing other generators to run less efficiently, including burning fuel while not generating electricity. See and

2. Pertaining to health — I’ve heard very mixed messages about whether the health effects are of legitimate concern and I would like to hear your take on it. ... Any scientific information would be great!

21 published (peer-reviewed) studies:
10 non-industry, non-government reviews:

One hitch has been the term “annoyance” as used in these studies. In epidemiology it means to a degree that can cause health problems. The wind industry has instead used its colloquial meaning to characterize the problem as something people just need to get used to.

Even that flies in the face of the evidence that infrasound (frequencies below the threshold of conscious hearing) and low-frequency noise (ILFN) is probably responsible for much of the problem, because research suggests that people who are sensitive to ILFN become more sensitized with continued exposure.

The research showing that people complain more about wind turbine noise than other artificial sources at similar decibel levels is probably explained by the facts that it is unpredictable (depending on wind speed and direction), that it often occurs at night, and that it is a pulsating noise.

Basically, the wind industry is trying to stop research as it has just begun. Because, as the reviews conclude, the preliminary research clearly justifies concern and is already leading to revisions of noise regulations to consider lower frequencies and pulsating patterns. And if such regulations are justified for humans, they would also have to be considered for wildlife ...

3. For my own sanity, I’m wondering why on earth there is so much controversy! How can there be such polar opposite opinions and what is the truth ... in your opinion?

There is a lot of desperation and urgency to remedy the consequences of our high level of energy consumption, and big wind has exploited that, ever since Enron first realized that it could sell wind to environmentalists as an alternative to coal. Since concern about climate change came to dominate mainstream environmentalism after Al Gore’s movie, wind energy has been sold as our salvation. It became a “with us or against us” marker of one’s concern for the environment or sociopolitical team loyalty. Its own adverse impacts (mining, birds and bats, wild habitat) are then dismissed simply as being much less than those of fossil fuels (the other team), ignoring the fact the the reduction of fossil fuel burning because of wind energy is effectively nil, making wind’s impacts — many of them unique, such as the threats to raptors and bats, and the need to build over hundreds of acres at a time in rural and wild places — an addition, not an alternative. Even the American Wind Energy Association once admitted that the most ambitious wind program would only slow the increase of carbon emissions. And for greenhouse gases, there are still the problems of transport and heating. And animal agriculture. And hydrofluorocarbons.

The truth is that there is no free lunch. By approaching the problem with building more instead of using less, wind energy is only perpetuating it. And while people look to wind energy to save the planet, they are more likely to avoid doing things that would make a real difference. They are able to buy Enron-invented “green tags” (carbon credits) to “offset” their impact rather than actually reduce it.

So the polarity is indeed justified and inevitable. Once somebody realizes that wind is a nonsolution, and harmful itself without meaningfully mitigating other harms, it is clear that there is hardly a “middle ground”. And once someone who believes in wind starts to admit that it has drawbacks or that claims for its benefits are overblown, a cornerstone of mainstream environmentalism starts to crumble — and retrenchment becomes all the more fierce to avoid complicating “the message”.

4. One more question: What are viable solutions instead of wind energy, and if wind energy is here to stay what kind of regulations or changes are needed for it to be successful?

Frankly, there probably isn’t a viable solution right now to 8 billion humans consuming ever more resources, particular in a world economic model of “growth”, which even with the modifier “sustainable” is still growth — growth of consumption, growth of waste, and less for the rest of life on the planet. Thursday's Democracy Now had a couple of climate scientists on calling for radical change from that model:

As for the potential success of wind energy, it would require not only massive building of wind turbines (and all the resources they require) but also an even more massive battery backup system (and all the more resources) and a massive expansion of continent-wide high-capacity transmission lines. In other words, it’s ridiculous. Virtually everything would have to be turned over to wind energy. We would have instead of a war economy a wind economy, where wind energy powers primarily the maintenance of wind power. And we’d still need backup generators!

H.G. Wells wrote, in 1897, “A Story of the Days to Come”:
And all over the countryside, he knew, on every crest and hill, where once the hedges had interlaced, and cottages, churches, inns, and farmhouses had nestled among their trees, wind wheels similar to those he saw and bearing like vast advertisements, gaunt and distinctive symbols of the new age, cast their whirling shadows and stored incessantly the energy that flowed away incessantly through all the arteries of the city. ... The great circular shapes of complaining wind-wheels blotted out the heavens ...
In that story, it is indeed the power company that is in power.

That said, it is a fact that wind turbines are being and will continue to be built, so like National Wind Watch I strongly support effective setbacks (at least 2 km, perhaps 5 km) from homes and noise regulations (that limit nighttime indoor noise to 30 dBA, as the WHO recommends, and limit ILFN and pulsating noise as well). And we oppose opening up otherwise protected land to the construction of the giant machines. Of course, such regulation would not contribute to, but instead would threaten, the “success” of wind energy. It would remain rare and unprofitable, as such an absurd source of energy for the modern world should be, used only in the most desperate of circumstances when nothing else is possible and the cost and harm and low benefit might be justifiable.

wind power, wind energy, wind turbines, wind farms, environment, environmentalism

Thursday, November 21, 2013

How much does wind energy reduce carbon emissions?

Claims of wind energy reducing carbon emissions and water use are like my taking a walk and then claiming I prevented the emissions of driving instead. Except neither I nor anybody else might have made that drive, and I didn't check if anybody’s driving was actually prevented or displaced by my taking that walk.

Claims of wind energy reducing carbon emissions and water use are made only on the basis of how much electricity is generated by wind turbines and multiplying that by the average (if they are that rigorous) carbon intensity of the rest of the grid.

But that ignores several factors that likely reduce that equivalence:
  • Because wind is variable, it is more likely to displace no-carbon hydro and lower-carbon natural gas, not coal, because those generators can ramp up and down much more quickly than coal plants are able to.
  • In balancing the variability of wind, fossil fuel plants are forced to run less efficiently, i.e., burn more fuel per unit of energy generated.
  • Wind also takes advantage of the redundancy already built into the grid that keeps a substantial amount of capacity on spinning standby to be able to instantly switch to generation in case of a major failure of supply elsewhere — or a dip in wind generation. Therefore, at modest penetration levels (perhaps up to around 6%), wind probably has no effect on emissions at all, instead only switching already running backup plants between generation and standby more often. At greater penetration levels, connections to other grids (such as Denmark’s to Germany and the rest of Scandinavia) are used for that purpose.
That’s why wind’s benefits are always reported in terms of equivalences. Its advocates tireless avoid presenting actual data of less burning of fossil fuels, because, for the reasons given above, such data do not show much, if any, benefit at all.

wind power, wind energy, environment, environmentalism

Saturday, November 16, 2013

Wind displaces …

Here are a couple of pictures of the generation mix on the electric grids from two very different locations. These times were not chosen for any particular reason except that your editor was just now looking at them and though he/she might write about them. First, 24 hours from Spain:

What is notable is that only 3 sources vary substantially: wind, solar, and hydro. And gas use goes up a bit for the midday and evening peaks. As wind rises early in the morning and does not decrease after the midday peak, it is clear that hydro is the source being adjusted to accommodate it. It is also clear that there is substantial hydro capacity that is drawn on for the evening peak (when there is no solar). One might therefore conclude that the large amount of wind power installed in Spain has served more to reduce the use of hydropower rather than fossil fuels.

Second, a week from the Pacific Northwest in the USA:

What is notable here is the effect on other sources of the steady rise of wind-powered generation over the past 3 days. It's harder to read than the Spanish graph, but the effect seems to be almost none.

Update, Dec. 4, 2013:

wind power, wind energy, environment, environmentalism

6 Problems with Wind Turbine Syndrome by Skeptoid Brian Dunning

(Skeptoid episode #4388 — Most of the following is by courtesy of commenter El Rucio.)

Problem #1: There is no consensus on what it does or who it affects.

1. It is the consistency of symptoms reported by significant numbers of people after large wind turbines began operating nearby that led to the conclusion that those symptoms were probably caused by the turbines.

Problem #2: The symptoms attributed to Wind Turbine Syndrome do not require any cause.

2. It was Nina Pierpont's insight that the combination of symptoms and the pattern of susceptibility were signs of inner ear disturbance, suggesting infrasonic and/or low-frequency noise as the cause. Other physicians have noted that many of the symptoms can be caused by sleep disturbance due to the pulsating peaks of audible "blade swish". In any case, the symptoms vary with wind strength and direction and quite clearly diminish when affected individuals leave the area of the turbines or the turbines stop operating.

Problem #3: The timing of complaints is too unlikely.

3. PubMed lists 21 studies of the health effects of wind turbine noise published from 2003 to 2012, 9 of them dating from before Pierpont's book. In 2006, the French Academy of Medicine recognized the impact of wind turbine noise on human health and recommended a 1.5-km minimum distance from homes. Also in 2006, the British Noise Association wrote about the infrasound from wind turbines and recommended a setback of 1-1.5 miles.

Problem #4: The geographic dispersion of complaints is too unlikely.

4. Again, 21 studies published in English show a correlation, and only 7 of them come from English-speaking countries. Furthermore, most of the research showing the physiological effects of infrasound and low-frequency noise over the past few decades has been in non-English-speaking countries (see item 5). A review was recently recently published in Lakartidningen, the Journal of the Swedish Medical Association: "Infrasound From Wind Turbines – An Overlooked Health Hazard". In the comments of that article, the author, a specialist in otoneurology, addresses many of the arguments attempted here to dismiss the evidence.

Problem #5: Only implausible causes have been suggested.

5. PubMed lists well over 100 studies of the physiological effects of infrasound. And infrasound levels of concern from wind turbines have indeed been measured in homes. When Denmark proposed adding infrasound to its noise regulations in 2011, the wind industry forced the government to water it down.

Problem #6: Almost nobody seems to agree that it exists.

6. There is a list of 35 – at latest count – reviews of the health effects of wind turbines, and those by physicians overwhelmingly express concern and the need for further research and revised regulation.

[Problem #7:] Wind Turbine Syndrome ... bears all the signs of a psychogenic condition.

7. If there is any psychogenic condition around this issue, it is clearly the determination of so many otherwise intelligent people to vehemently deny the mounting evidence.

But at Skeptoid, all science is settled, all knowledge is absolute, and Brian Dunning, entrepreneur/convicted felon (read: huckster), is the final arbiter of both.

This whole subculture of smartypants skepticism is a sad aspect of our fascist era. Their pose of intellectual rigor appears more often to be simple contempt for people who think differently from them, and often as a desperate attempt to avoid facing facts that don't fit their vision of a technocratic utopia (or sales plan). Why do they feel so threatened? Why is the truth as they see it so unconvincing to others? Perhaps their own cultishness (like, never wondering what makes Brian Dunning such a know-it-all) betrays their claim of reason. Any reasonable person would be a lot more skeptical than these servants of power.

For their keen eye seems to be quite selectively applied to industries, since the "skeptics" themselves are invariably promoting or directly profiting by several of them, for example, industrial wind energy development. As in this episode, a lazy attempt to refute evidence of adverse health effects due to noise from wind turbines transparently serves only to promote wind energy companies by defaming their victims and those who listen to them. It is a contemptible performance, and it has nothing to do with science.

wind power, wind energy, wind turbines, wind farms, environment, environmentalism, human rights, animal rights

Friday, November 15, 2013

Reviews of wind turbines’ effects on human health

Elsewhere on this blog, there is an inclusive list of reviews of the literature concerning human health and the noise from industrial wind turbines. It was compiled to provide a more complete list than the highly selective one presented by Simon Chapman of the University of Sydney that is often cited by wind power promoters. It also showed that while Chapman presented the reviews as reason to dismiss health concerns, most of them actually note the limited number and power of studies but that the evidence justifies further investigation and caution.

Most of the reviews, however, are government reports: nine of Chapman’s original 17, all of the three he later added, and five of the additional reviews listed earlier on this blog. Furthermore, of Chapman’s list, four are irrelevant (three not about wind turbines and one a press release about one of the other reviews), two are industry reports, and two are just rehashes of an earlier review. Only three of the reviews he originally listed merit attention:
  • Dani Fiumicelli: Wind farm noise dose response: A literature review. Acoustics Bulletin, November/December 2011 (pages 26-35). [link]
  • Loren Knopper & Christopher Ollson: Health effects and wind turbines: A review of the literature. Environmental Health, 2011 10:78. [link]
  • Committee on Environmental Impacts of Wind-Energy Projects, Board on Environmental Studies and Toxicology, Division on Earth and Life Studies, National Research Council of the National Academies [NRC]: Environmental impacts of wind-energy projects. 2007. [link]
Ignoring additional government, industry, and unpublished reviews, we also have the following (in reverse order by date):
  • Patrice Tran Ba Huy, l’Académie nationale de médecine [France]: Nuisances Sanitaires des Éoliennes Terrestres. [Health Impacts of Onshore Wind Trubines.] May 9 2017. [link]
  • J. H. Schmidt, M. Klokker: Health effects related to wind turbine noise exposure: a systematic review. PLoS One 9(12): e114183 (2014). [link]
  • R. J. McCunney, K. A. Mundt, W. D. Colby, R. Dobie, K. Kaliski, & M. Blais: Wind turbines and health: a critical review of the scientific literature. Journal of Occupational and Environmental Medicine 2014 Nov;56(11):e108-30. “The Canadian Wind Energy Association funded this project.” These authors produced a similar review for the American and Canadian Wind Energy Associations in 2009. [link]
  • Loren Knopper, Christopher Ollson, et al.: Wind turbines and human health. Frontiers in Public Health 2014;2:63. [link]
  • Ian Arra, Hazel Lynn, Kimberley Barker, Chiebere Ogbuneke, & Sophie Regalado: Systematic Review 2013: Association between Wind Turbines and Human Distress. Cureus 6(5):e183. [link]
  • Michael Nissenbaum: Industrial Wind Turbines, Human Variability, and Adverse Health Effects. New England College of Occupational and Environmental Medicine Reporter, Volume 2 Issue 38 Fall 2013. [link]
  • Håkan Enbom & Inga Malcus Enbom: Infraljud från vindkraftverk – en förbisedd hälsorisk. [Infrasound from wind turbines – an overlooked health hazard.] Lakartidningen [Journal of the Swedish Medical Association], 2013 Aug 7-20;110(32-33):1388-9. [link]
  • Donata Kurpas, Bozena Mroczek, Beata Karakiewicz, Krzysztof Kassolik, & Waldemar Andrzejewski: Health impact of wind farms. Annals of Agricultural and Environmental Medicine 2013, Vol 20, No 3, 595–605. [link]
  • Jennifer Roberts & Mark Roberts: Wind turbines: is there a human health risk? Journal of Environmental Health, April 2013, Volume 75, No. 8. [link]
  • Con Doolan: A Review of Wind Turbine Noise Perception, Annoyance and Low Frequency Emission. Wind Engineering, Volume 37, No. 1, 2013, pp 97-104. [link]
  • Amir Farboud, R. Crunkhorn, & A. Trinidade: ‘Wind turbine syndrome’: fact or fiction? Journal of Laryngology & Otology, Volume 127, Issue 03, March 2013, pp 222-226. [link]
  • Christopher Hanning & Alun Evans: Wind turbine noise [editorial]. BMJ [British Medical Journal] 2012;344:e1527. [link]
  • Richard R. James: Wind turbine infra and low-frequency sound: warning signs that were not heard. Bulletin of Science, Technology & Society, 32(2) 108-127 (2012). [link]
  • Erwin Quambusch & Martin Lauffer: Infraschall von Windkraftanlagen als Gesundheitsgefahr. [Infrasound from wind turbines as a health hazard.] ZFSH/SGB–Zeitschrift für die sozialrechtliche Praxis 08/2008. [link]
  • Claude-Henri Chouard, l’Académie nationale de médecine [France]: Le retentissement du fonctionnement des éoliennes sur la santé de l’homme. [Repercussions of wind turbine operations on human health.] March 2006. [link]
  • Marjolaine Villey-Migraine: Eoliennes, sons et infrasons: Effets de l’éolien industriel sur la sante des hommes [thesis]. [Wind turbines, noise, and infrasound: effects of industrial wind turbines on human health.] Université Paris II–Panthéon-Assas, December 2004. [link]
Vetting these eleven, we find that: Dani Fiumicelli is Technical Director (Head of Noise and Vibration) of Temple Group, a development consultancy in the U.K., and is an author of a 2013 report for the Scottish government to deny concerns of health effects; Loren Knopper is Senior Scientist and Christopher Ollson is Vice President for Strategic Development of Intrinsik, an environment and health consultancy in Ontario, and in their paper they disclose that they “have worked with wind power companies”, that Ollson “has acted as an expert witness for wind power companies during a number of legal hearings”, and that all of the authors of their 2014 review are also disclosed to be employees of Intrinsik: “the authors work for a consulting firm and have worked with wind power companies”; in 2015 the Canadian Wind Energy Association honored Knopper and Ollson with their R. J. Templin Award for “results that have served to significantly advance the wind energy industry in Canada”; Mark Roberts is Principal Scientist of Exponent, an engineering and scientific consulting firm involved in wind energy development; and Kurpas et al. mention in passing towards the end of their paper that they “are involved in community public consultations with the advocates of new projects”. These potential conflicts are noted in the following quotes (ordered by date).

Villey-Migraine: “Wind turbines emit infrasound, this is not disputed by anyone. ... It seems to us immoral on the part of this organization [Agency of the Environment and Energy Management] to assert, without any reference, that infrasound emitted by wind turbines is perfectly harmless, and furthermore, to make claims of so-called ‘action,’ but that we can not prove the impact of wind turbine infrasound on humans by epidemiological studies. ... Noise and infrasound emitted by wind turbines have a definite impact on the health of humans and can harm people’s lives. ... Wind developers have a responsibility to put in place adequate measures to reduce the risks of damage to the health of residents living near wind turbines by siting turbines no closer to homes than – not 500 m as suggested in their publications – but 1600 m considering audible noise and at least 5 km considering infrasound.” [translated]

Chouard: “Whether it is quite intense or it represents a more moderate noise pollution, noise is the complaint most frequently made concerning wind turbines. It can have a real impact, and so far disregarded, on human health. ... It would be desirable, as a precaution, to halt the construction of wind turbine facilities greater than 2.5 MW closer than 1500 meters from homes.” [translated]

NRC: “In the absence of extensive data, this report focuses mainly on appropriate methods for analysis and assessment and on recommended practices in the face of uncertainty. ... Low-frequency vibration and its effects on humans are not well understood. Sensitivity to such vibration resulting from wind-turbine noise is highly variable among humans. ... More needs to be understood regarding the effects of low-frequency noise on humans.”

Quambusch & Lauffer: “There is no doubt that wind turbines produce infrasound. In contrast to the pronouncements of the authorities, plant operators, and related institutions that infrasound is "completely harmless", there are an increasing number of scientists noting the health risks of infrasound. The risk is sufficient that new regulations are required for prevention. As long as and to the extent that the health risks are not prevented by technical or similar guidelines, construction and operation of these plants should be allowed only if they are out of sight of residential areas.” [translated]

Knopper &: Ollson [industry consultants, non-medical]: “wind turbines can be a source of annoyance for some people”

Fiumicelli [industry consultant, non-medical]: “uncertainty about human response to wind turbine noise”

James [acoustician, non-medical]: “There is sufficient research and history to link the sensitivity of some people to inaudible amplitude-modulated infra and low-frequency noise to the type of symptoms described by those living near industrial wind turbines.”

Hanning & Evans: “A large body of evidence now exists to suggest that wind turbines disturb sleep and impair health at distances and external noise levels that are permitted in most jurisdictions ... Sleep disturbance may be a particular problem in children, and it may have important implications for public health. ... Robust independent research into the health effects of existing wind farms is long overdue.”)

Farboud et al.: “There is some evidence of symptoms in patients exposed to wind turbine noise. The effects of infrasound require further investigation.”

Doolan: “Low-frequency noise levels from wind turbines may exceed audibility thresholds and thus it is possible that they are correlated with annoyance. A review of studies related to general low-frequency noise annoyance shows there are similarities with annoyance studies involving wind turbine noise. ... noise levels may comply with existing environmental noise guidelines based on the dB(A) scale yet still cause annoyance due to the uniqueness of low-frequency noise problems. However, there is very little information (level, spectral balance, temporal qualities, etc) regarding low-frequency noise in people’s homes affected by wind turbines. ... Thus more research is needed in understanding the fundamental aspects of wind turbine low-frequency noise generation, propagation and perception.”

Roberts & Roberts [industry consultants]: “The answer to the question of whether or not exposure to wind turbine sound is a human health risk is still under review and warrants further research. Although limited, research has demonstrated that LFS [low-frequency sound] can elicit adverse physical health effects, such as vibration or fatigue, as well as an annoyance or unpleasantness response. The current research on exposure to wind turbine sound and the mere presence of wind turbines have also demonstrated a significant annoyance response among study participants. But the association and particular pathway between LFS specifically generated from wind turbines, annoyance, and adverse physical health effects have yet to be fully characterized.” [These authors also ignore the Nissenbaum et al. study in Noise & Health.]

Kurpas et al. [industry consultants]: “Short description of state of the art: The nuisance caused by wind turbines is stereotypically linked with the noise that they produce. Nevertheless, the visual aspect of wind farms, opinions about them, and sensitivity to sound seem to be of the greater importance. ... Health effects are more probably associated with some environmental factors leading to annoyance or frustration. All types of studies share the same conclusion: wind turbines can provoke annoyance. ... The influence of wind turbines on human emotional and physical health is a relatively new field of research. Further analyses of these issues are justified, especially because none of the studies published in peer-reviewed journals so far meet the criteria for cohort or case-control studies. ... The authors did not analyse coherent publications or website documents (study by M. Alves-Pereira and N.C. Branco and the study by N. Pierpont).” [The authors also missed the Nissenbaum 2012 paper in Noise & Health, which appeared after their submission. And they assert that noise from wind turbines cause only subjective effects, despite the evidence under review of interference with, e.g., sleep, and physiological effects.]

Enbom & Malcus Enbom: “Infrasound from wind turbines affects the inner ear and is a potential health risk for people with migraine or other type of central sentitisation. Regulations for construction of wind turbines should be revised, taking this fact into account.” [translated]

Nissenbaum: “In summary, in many IWT projects, the preconstruction sound modeling has underestimated the eventual real world sound levels those turbine projects eventually produce. When coupled with the underappreciated human physiological responses to the type of noise large turbines produce (adverse sleep and mental health effects), this has had real world consequences for those living near them. The relationship of noise to sleep disturbances is established. The biological plausibility of sleep disturbances resulting in ill health is settled science. Chronic noise exposure leads to chronic sleep disturbance in many of those exposed, often resulting in ill health. Observed adverse human effects must trump preconstruction sound modeling; changes in practice must occur when there are errors. It’s all about distance when siting decisions are made.”

Arra et al.: “In this review, we have demonstrated the presence of reasonable evidence (Level Four and Five) that an association exists between wind turbines and distress in humans. The existence of a dose-response relationship (between distance from wind turbines and distress) and the consistency of association across studies found in the scientific literature argues for the credibility of this association.”

Knopper, Ollson, et al. [industry consultants, non-medical]: “Setbacks should be sound-based rather than distance-based alone. Preference should be given to sound emissions of ≤40 dB(A) for non-participating receptors, measured outside, at a dwelling, and not including ambient noise. ... Post construction monitoring should be common place to ensure modeled sound levels are within required noise limits. If sound emissions from wind projects is in the 40–45 dB(A) range for non-participating receptors, we suggest community consultation and community support. Setbacks that permit sound levels >45 dB(A) (wind turbine noise only; not including ambient noise) for non-participating receptors directly outside a dwelling are not supported due to possible direct effects from audibility and possible levels of annoyance above background. When ambient noise is taken into account, wind turbine noise can be >45 dB(A), but a combined wind turbine–ambient noise should not exceed >55 dB(A) for non-participating and participating receptors. Our suggested upper limit is based on WHO conclusions that noise above 55 dB(A) is ‘considered increasingly dangerous for public health,’ is when ‘adverse health effects occur frequently, a sizeable proportion of the population is highly annoyed and sleep-disturbed’ and ‘cardiovascular effects become the major public health concern, which are likely to be less dependent on the nature of the noise.’”

Schmidt and Klokker: “At present it seems reasonable to conclude that noise from wind turbines increases the risk of annoyance and disturbed sleep in exposed subjects in a dose-response relationship. There seems to be a tolerable limit of around LAeq of 35 dB. Logically, accepting higher limits in legislations may lead to increased numbers of annoyed subjects. It therefore seems reasonable to conclude that a cautious approach is needed when planning future wind farms. Furthermore, there is an indication that noise annoyance and sleep disturbance are related and that disturbed sleep potentially can lead to adverse health effects. These conclusions are, however, affected by a potential risk for selection and information bias even in the larger cross-sectional studies providing the current best evidence. The evidence for adverse health effects other than sleep disturbance is primarily supported by case-series reports which certainly may be affected by various sources of bias. Larger cross-sectional surveys have so far been unable to document a relationship between various symptoms such as tinnitus, hearing loss, vertigo, headache and exposure to wind turbine noise. One limitation causing this could be that most studies so far have only measured LAeq or Lden. An additional focus on the measurement of low-frequency sound exposure as well as a more thorough characterisation of the amplitude modulated sound and the relationship between objective and subjective health parameters could lead to different conclusions in the future. Finally, in regards to the objective measurement of health-related disorders in relation to wind turbine noise, it would be valuable to demonstrate if such health-related outcomes fluctuate depending on exposure to wind turbine noise.”

Tran Ba Huy: “[L]e caractère intermittent, aléatoire, imprévisible, envahissant du bruit généré par la rotation des pales, survenant lorsque le vent se lève, variant avec son intensité, interdisant toute habituation, peut indubitablement perturber l’état psychologique de ceux qui y sont exposés. Ce sont notamment les modulations d’amplitudes causées par le passage des pales devant le mât qui sont dénoncées comme particulièrement dérangeantes.” [The intermittent, random, unpredictable, invasive character of the noise generated by the rotation of the blades, arising when the wind rises and varying along with its intensity, preventing habituation, can undoubtedly disturb the psychological state of those who are exposed to it. These include amplitude modulation caused by the passage of the blades in front of the mast, which is noted as particularly disturbing.] “[L]e groupe de travail recommande: ... de revenir pour ce qui concerne leur bruit (et tout en laissant les éoliennes sous le régime des Installations Classées pour le Protection de l’Environnement) au décret du 31 août 2006 relatif à la lutte contre les bruits du voisinage (relevant du code de Santé publique et non de celui de l’Environnement), ramenant le seuil de déclenchement des mesures d’émergence à 30 dB A à l’extérieur des habitations et à 25 à l’intérieur.” [The working group recommends returning to the decree of 31 August 2006 concerning the fight against neighborhood noise, reducing the the threshold for emergency measures to [ambient levels] 30 dBA outside residences and 25 dBA inside [limiting wind turbine noise to +5 dBA in daytime (7am–10pm) and +3 dBA at night (10pm–7am)].]

To undertake your own review, click here for a list of, and access to, 21 published studies (2003–2012) of health effects of industrial wind turbine noise.

Also see the tables from “Health Effects Related to Wind Turbine Noise Exposure: A Systematic Review” by JH Schmidt and M Klokker (2014)

wind power, wind energy, wind turbines, wind farms, human rights

Thursday, November 14, 2013

Two-thirds of dementia cases have unknown causes

“Much of late life cognitive decline is not due to common neurodegenerative pathologies”. Patricia A. Boyle, PhD, Robert S. Wilson, PhD, Lei Yu, PhD, Alasdair M. Barr, PhD, William G. Honer, MD, Julie A. Schneider, MD, and David A. Bennett MD. Annals of Neurology. Volume 74, Issue 3, pages 478–489, September 2013. DOI: 10.1002/ana.23964

Objective. The pathologic indices of Alzheimer disease, cerebrovascular disease, and Lewy body disease accumulate in the brains of older persons with and without dementia, but the extent to which they account for late life cognitive decline remains unknown. We tested the hypothesis that these pathologic indices account for the majority of late life cognitive decline.

Methods. A total of 856 deceased participants from 2 longitudinal clinical–pathologic studies, Rush Memory and Aging Project and Religious Orders Study, completed a mean of 7.5 annual evaluations, including 17 cognitive tests. Neuropathologic examinations provided quantitative measures of global Alzheimer pathology, amyloid load, tangle density, macroscopic infarcts, microinfarcts, and neocortical Lewy bodies. Random coefficient models were used to examine the linear relation of pathologic indices with global cognitive decline. In subsequent analyses, random change point models were used to examine the relation of the pathologic indices with the onset of terminal decline and rates of preterminal and terminal decline (ie, nonlinear decline).

Results. Cognition declined a mean of about 0.11U per year (estimate = −0.109, standard error [SE] = 0.004, p < 0.001), with significant individual differences in rates of decline; the variance estimate for the individual slopes was 0.013 (SE = 0.112, p < 0.001). In separate analyses, global Alzheimer pathology, amyloid, tangles, macroscopic infarcts, and neocortical Lewy bodies were associated with faster rates of decline and explained 22%, 6%, 34%, 2%, and 8% of the variation in decline, respectively. When analyzed simultaneously, the pathologic indices accounted for a total of 41% of the variation in decline, and the majority remained unexplained. Furthermore, in random change point models examining the influence of the pathologic indices on the onset of terminal decline and the preterminal and terminal components of the cognitive trajectory, the common pathologic indices accounted for less than a third of the variation in the onset of terminal decline and rates of preterminal and terminal decline.

Interpretation. The pathologic indices of the common causes of dementia are important determinants of cognitive decline in old age and account for a large proportion of the variation in late life cognitive decline. Surprisingly, however, much of the variation in cognitive decline remains unexplained, suggesting that other important determinants of cognitive decline remain to be identified. Identification of the mechanisms that contribute to the large unexplained proportion of cognitive decline is urgently needed to prevent late life cognitive decline.