Wind farms are hardly the bird slayers they’re made out to be. Here’s why


File 20170616 512 12qly6u
The potential to harm local birdlife is often used to oppose wind farm development. But research into how birds die shows wind farms should be the least of our concerns.
from www.shutterstock.com

Simon Chapman, University of Sydney

People who oppose wind farms often claim wind turbine blades kill large numbers of birds, often referring to them as “bird choppers”. And claims of dangers to iconic or rare birds, especially raptors, have attracted a lot of attention.

Wind turbine blades do indeed kill birds and bats, but their contribution to total bird deaths is extremely low, as these three studies show.

A 2009 study using US and European data on bird deaths estimated the number of birds killed per unit of power generated by wind, fossil fuel and nuclear power systems.

It concluded:

wind farms and nuclear power stations are responsible each for between 0.3 and 0.4 fatalities per gigawatt-hour (GWh) of electricity while fossil-fuelled power stations are responsible for about 5.2 fatalities per GWh.

That’s nearly 15 times more. From this, the author estimated:

wind farms killed approximately seven thousand birds in the United States in 2006 but nuclear plants killed about 327,000 and fossil-fuelled power plants 14.5 million.

In other words, for every one bird killed by a wind turbine, nuclear and fossil fuel powered plants killed 2,118 birds.

A Spanish study involved daily inspections of the ground around 20 wind farms with 252 turbines from 2005 to 2008. It found 596 dead birds.

The turbines in the sample had been working for different times during the study period (between 11 and 34 months), with the average annual number of fatalities per turbine being just 1.33. The authors noted this was one of the highest collision rates reported in the world research literature.

Raptor collisions accounted for 36% of total bird deaths (214 deaths), most of which were griffon vultures (138 birds, 23% of total mortality). The study area was in the southernmost area of Spain near Gibraltar, which is a migratory zone for birds from Morocco into Spain.

Perhaps the most comprehensive report was published in the journal Avian Conservation and Ecology in 2013 by scientists from Canada’s Environment Canada, Wildlife Research Division.

Their report looked at causes of human-related bird deaths for all of Canada, drawing together data from many diverse sources.

The table below shows selected causes of bird death out of an annual total of 186,429,553 estimated deaths caused by human activity.

https://datawrapper.dwcdn.net/Zg2hk/1/

Mark Duchamp, the president of Save the Eagles International is probably the most prominent person to speak out about bird deaths at wind farms. He says:

The average per turbine comes down to 333 to 1,000 deaths annually which is a far cry from the 2-4 birds claimed by the American wind industry or the 400,000 birds a year estimated by the American Bird Conservancy for the whole of the United States, which has about twice as many turbines as Spain.

Such claims from wind farm critics generally allude to massive national conspiracies to cover up the true size of the deaths.

And in Australia?

In Australia in 2006 a proposal for a 52-turbine wind farm plan on Victoria’s south-east coast at Bald Hills (now completed) was overruled by the then federal environment minister Ian Campbell.

He cited concerns about the future of the endangered orange-bellied parrot (Neophema chrysogaster), a migratory bird said to be at risk of extinction within 50 years. The Tarwin Valley Coastal Guardians, an anti wind farm group that had been opposing the proposed development.

Interest groups have regularly cited this endangered bird when trying to halt a range of developments.

These include a chemical storage facility and a boating marina. The proposed Westernport marina in Victoria happened to also be near an important wetland. But a professor in biodiversity and sustainability wrote:

the parrot copped the blame, even though it had not been seen there for 25 years.

Victoria’s planning minister at the time, Rob Hulls, described the Bald Hills decision as blatantly political, arguing the federal conservative government had been lobbied by fossil fuel interests to curtail renewable energy developments. Hulls said there had been:

some historical sightings, and also some potential foraging sites between 10 and 35 kilometres from the Bald Hills wind farm site that may or may not have been used by the orange-bellied parrot.

Perhaps the final word on this topic should go to the British Royal Society for the Protection of Birds. It built a wind turbine at its Bedfordshire headquarters to reduce its carbon emissions (and in doing so, aims to minimise species loss due to climate change). It recognised that wind power is far more beneficial to birds than it is harmful.


The ConversationSimon Chapman and Fiona Crichton’s book, Wind Turbine Syndrome: a communicated disease, will be published by Sydney University Press later this year.

Simon Chapman, Emeritus Professor in Public Health, University of Sydney

This article was originally published on The Conversation. Read the original article.

The stampede of wind farm complaints that never happened



Image 20170406 16654 gto650
Why were so few complaints about wind farms investigated further? And who made these complaints anyway?
from www.shutterstock.com

Simon Chapman, University of Sydney

National Wind Farm Commissioner, Andrew Dyer, has just released his much anticipated first annual report. The Conversation

In its first year of operation until the end of 2016, the National Wind Farm Commissioner says his office received:

  • 46 complaints relating to nine operating wind farms (there were 76 operational wind farms in Australian in 2015)

  • 42 complaints relating to 19 proposed wind farms

  • two complaints that did not specify a wind farm.

The commissioner’s office closed 67 or these 90 complaints, with the remaining 23 complaints still in process.

Of the 67 now-closed complaints, the office closed 31 because the complainant did not progress their complaint. This suggests these complaints were minor.

The office closed the file on another 32 after it sent complainants more information about their complaints.

This leaves only four, which the report describes two as being settled after negotiations between the parties, and two given the ambiguous category of “other”.

These figures are frankly astonishing.

The complaint investigating mechanism was set up after a Senate enquiry report that cost undisclosed millions to deal with a “massive” problem with wind turbines.

But the hordes of people who apparently needed a way to help them resolve matters have now gone shy.

Chair of the Senate Committee on Wind Turbines was ex-Senator John Madigan, a public critic of wind farms.

John Madigan speaking out against wind farms at the National Wind Power Fraud Rally in 2013.

Other members who signed off on the senate inquiry report included Senator Nick Xenophon, another long-time critic.

Senator Nick Xenophon criticising wind turbines on the Seven Network’s Today Tonight in 2012.

Complaints vs complainants

The National Wind Farm Commissioner’s first annual report avoids two key issues.

First, it doesn’t mention how many complainants made the 90 complaints. The anti-wind farm “movement” in Australia is often busy plaguing politicians and the few supportive media outlets that give it time.

One woman from Victoria often sends out emails to well over 100 politicians and journalists. Others join her to try to demonise wind turbines. Those in this small group appear again and again as submission authors to what have now been three senate enquires and two state government enquiries.

This phenomenon is well known in government circles. In the last three months of 2016, just 10 people submitted half of Heathrow Airport’s 25,000 noise complaints.

The second omission from the annual report is any mention of its budget or expenditure. The Office of the National Wind Farm Commissioner is independent and has its own website. But unless I missed it, there are no budget or expenditure figures in either the annual report nor the website. Is this a first for an annual report?

We know that commissioner Andrew Dyer gets A$205,000 a year for his part-time role, on a three year contract. With the numbers we now have about the low number of complaints, this sounds like a tough gig. But what about the staff and office costs, which are nowhere to be found.

No complaints in Western Australia and Tasmania

As I reported in my 2013 peer reviewed report into wind farm complaints, there were no records of complaints for Western Australia and Tasmania.

Of the total complaints about operational or planned wind farms, 40 came from Victoria, and 23 from each of South Australia and New South Wales. Just two complaints were received from Queensland about planned farms.

Our study found records of only 129 people who had ever complained about wind farms since the first one was built in Western Australia in the 1980s.

Three years later, after the door is left open for complaints, a mere 90 are received from an unknown number of individuals.

Wind turbines and sickness?

This is all very awkward for those who argue wind turbines cause illness. How is it that if wind farms are a direct cause of illness, that 67 wind farms around the country (88%) saw not one complaint, about health or anything else across a whole year?

The stock answer given here by wind farm opponents is that wind farm illness is like sea sickness: only a few get it. So in the whole of two states, and across 88% of wind farms, there’s apparently no-one with susceptibility to wind farm illness.

Former Prime Minister Tony Abbott, who described wind farms as “ugly”, “noisy” and “visually awful”, threw the senate committee a giant political bone.

The committee, and the Office of the Wind Farm Commissioner, put up their “we’re open” shingle and invited the alleged throngs of suffering rural residents to air their problems.

This annual report shows very few did, and the great majority of “complaints” dissolved by being sent information.

This sorry episode in appeasing the wind farm obsessions of a tiny number of cross-bench senators needs to have its time called, fast.

Simon Chapman, Emeritus Professor in Public Health, University of Sydney

This article was originally published on The Conversation. Read the original article.

Alan Jones goes after wind farms again, citing dubious evidence


Simon Chapman, University of Sydney

Last week, Sydney radio announcer Alan Jones lambasted those concerned about climate change and what he called “renewable energy rubbish”.

Jones has been loose with the facts in the past, having been Factchecked in 2015 after confusing kilowatts with megawatts and quoting a cost for wind power he later confessed “where the 1502 [dollars per megawatt hour that he stated] comes from, I have absolutely no idea”.

Jones, who chaired the much hyped but poorly attended 2013 national rally against wind farms in June 2014 (see photo) told his listeners last week wind farms are “buggering up people’s health”.

He also said “harrowing evidence” had been given by sufferers to the 2014-15 Senate Select Committee on Wind Farms chaired by (now ex-) Senator John Madigan. He along with Bob Day, David Leyonhjelm, Chris Back and Nick Xenophon have been vocal opponents of wind farms.

Their report predictably savaged wind farms, while Labor Senator Anne Urquhart’s minority report was the only one I found to be evidence-based.

Jones then went on to interview Dr Mariana Alves-Periera, from the private Lusophona University in Portugal (world university ranking 1,805, and impact ranking 2,848) whom he described as a distinguished international figure.

She was “recognized internationally” and had published “over 50” scientific papers over 30 years, something of a modest output. Jones, who may or may not have read any of these publications, told listeners her findings were “indisputable”, there was “no opposing scientific evidence” and again in emphasis, “none of [her papers] have been disputed” to which Alves-Periera agreed instantly “no they haven’t”.

This is an interesting interpretation of the scientific reception that has greeted the work of the Lisbon group on the unrecognized diagnosis of “vibroacoustic disease” (or VAD), a term they have made their own.

I first encountered Alves-Periera when she spoke via videoconference to a NHMRC meeting on wind farms and health in 2011. She spoke to a powerpoint presentation which highlighted the case of a schoolboy who lived near wind turbines. Her claim was the boy’s problems at school were due to his exposure to the turbines, as were cases of “boxy foot” in several horses kept on the same property.

Intrigued by this n=1 case report, I set out with a colleague to explore the scientific reception that “vibroacoustic disease” had met. We published our findings in the Australian and New Zealand Journal of Public Health 2013.

We found only 35 research papers on VAD. None reported any association between VAD and wind turbines. Of the 35 papers, 34 had a first author from the Lusophona University-based research group. Remarkably, 74% of citations to these papers were self-citations by members of the group.

In other words, just shy of three quarters of all references to VAD were from the group who were promoting the “disease”. In science, median self-citation rates are around 7%. We found two unpublished case reports from the group presented at conferences which asserted that VAD was “irrefutably demonstrated” to be caused by wind turbines. We listed eight reasons why the scientific quality of these claims were abject.

In 2014 Alves-Periera and a colleague defended their work in a letter to the journal and I replied. They described themselves as the “lead researchers in vibroacoustic disease”. But as we had shown, they are almost the only researchers who were ever active on this topic, with self-citation rates seldom seen in research.

Other experts have taken a different view of the group’s work. One of the world’s leading acousticians Geoff Leventhall who also spoke at the NHMRC’s 2011 meeting, wrote in a 2009 submission to the Public Service Commission of Wisconsin about the Lisbon group’s VAD work.

The evidence which has been offered [by them] is so weak that a prudent researcher would not have made it public.

Another expert said:

vibroacoustic disease remains an unproven theory belonging to a small group of authors and has not found acceptance in the medical literature

And most recently, the UK’s Health Protection Agency said the:

disease itself has not gained clinical recognition.

Leventhall concluded his review by saying:

One is left with a very uncomfortable feeling that the work of the VAD group, as related to the effects of low levels of infrasound and low frequency noise exposure, is on an extremely shaky basis and not yet ready for dissemination. The work has been severely criticised when it has been presented at conferences. It is not backed by peer reviewed publications and is available only as conference papers which have not been independently evaluated prior to presentation.

Jones told his listeners the reason wind turbines are not installed on Bondi Beach, down Sydney’s Macquarie Street or Melbourne’s Collins Street was because governments “know they are harmful to health”. His beguiling logic here might perhaps also be the same reason we don’t see these iconic locations given over to mining or daily rock concerts. Most people would understand there are other factors that explain the absence of both wind turbines, mines or daily rock concerts in such locations.

Jones has given air time to a Victorian woman who is a serial complainant about her local wind farm and who has written:

Around the Macarthur wind farm, residents suffer from infrasound emitted by the turbines, even when they’re not operating.

At a time when we are seeing unparalleled increases in renewable energy and reductions in fossil fuels all over the world, one wonders why this is still public discussion in Australia.

The Conversation

Simon Chapman, Emeritus Professor in Public Health, University of Sydney

This article was originally published on The Conversation. Read the original article.

What’s next, a Senate inquiry into infrasound from trees, waves or air conditioners?


Simon Chapman, University of Sydney

At the centre of claims about wind farms allegedly causing health problems is the infrasound that wind turbines generate as they turn in the wind.

Infrasound is sound below 20Hz, which is generally inaudible. Wind turbines are just one source of artificial man-made infrasound. Others include power stations, industry generally, motor vehicle engines, compressors, aircraft, ventilation and air conditioning units, and loudspeaker systems. Everyone living in an urban environment is bathed in infrasound for most of their lives.

As I sit at my inner Sydney desk writing this I’m copping infrasound from the planes that pass some 200-300 metres over my house sometimes many times an hour, the sound of passing road traffic on a quite busy road 100 metres from our house, and the stereo system I listen to as I write. Don’t tell anyone, but I feel fine and I’ve lived here 25 years.

But infrasound is generated by natural phenomena too. These include rare occurrences such as volcanoes and earthquakes, but also sources like ocean waves and air turbulence (wind) that countless millions, if not billions, are exposed to on most days. Anyone living close to the sea is surrounded by constant infrasound from waves.

The inclusion of wind as a source of infrasound is of particular significance to claims made that wind turbine-generated infrasound is noxious. In a Polish research paper published in 2014, the authors set out to measure infrasound from wind turbines and to compare that with naturally occurring infrasound from wind in trees near houses and from the sound of the sea in and around a house near the seaside.

The researchers used the average G-weighted level (LGeq) over the measurement period. This is the standardised measurement of infrasound which approximately follows the hearing threshold below 20Hz and cuts off sharply above 20Hz.

The infrasound levels recorded near 25 100-metre high wind turbines ranged from 66.9 to 88.8 LGeq across different recordings. Those recording infrasound in noise from wind in a forest near houses ranged from 59.1- 87.8 LGeq. The recordings of sea noise near seaside houses ranged from 64.3 to 89.1 LGeq. These infrasound levels were thus very similar cross the three locations.

The peak 88.8 LGeq was recorded very close to the turbines – virtually directly under the blades. The lower 66.9LGeq was 500m away, which is more like a common scenario for the nearest residences to turbines. Similarly, for the other sources, highest levels were nearest the source.

Wind is, of course, a prerequisite for wind turbines to turn and generate their mechanical infrasound. Here, the Polish authors noted that:

natural noise sources … always accompany the work of wind turbines and in such cases they constitute an acoustic background, impossible to eliminate during noise measurement of wind turbines.

This is a fundamentally important insight: wherever there are wind turbines generating infrasound, there is also wind itself generating infrasound. And it is impossible to disentangle the two. Indeed, every time I’ve been near wind turbines, easily the most dominant sound has been that of the wind buffeting my ears.

In 2013, the South Australian Environmental Protection Authority measured infrasound in a variety of urban and rural settings. With the latter, this included locations near and well away from wind farms.

They reported that in urban settings, measured infrasound ranged between 60-70 decibels. In fact, at two locations – the EPA’s own offices and an office with a low frequency noise complaint – building air conditioning systems were identified as significant sources of infrasound. These locations exhibited some of the highest levels of infrasound measured during the study.

They concluded:

This study concludes that the level of infrasound at houses near the wind turbines assessed is no greater than that experienced in other urban and rural environments, and that the contribution of wind turbines to the measured infrasound levels is insignificant in comparison with the background level of infrasound in the environment.

Wind farm opponents claim infrasound is the cause of this Old Testament-like plague of plagues (now numbering 244 different problems). If that were true, how is it that hundreds of thousands of Australians who are daily exposed to infrasound in cities, in their houses surrounded by dastardly infrasound-generating fans, air conditioners and stereo systems, and those who live near trees or the sound of the ocean aren’t breaking down the door of those sworn enemies of infrasound Senators John Madigan, Nick Xenophon, Chris Back, David Leyonhjelm and Bob Day who brought us their scathing report on wind farms in June?

The explanation lies in factors we recognise frequently in risk-perception studies, popularised by Peter Sandman. Sandman has produced matrices of factors which have been often found to be associated with increased levels of community “outrage” about putative environmental threats to health.

Sandman distinguishes primary from additional factors, with primary factors being those which have been shown to be more strongly associated with increased levels of community concern.

I applied these to a case study of mobile phone tower complaints in the 1990s. I’ve now constructed the table below indicating the likely applicability of these factors to the case of predicting community worry about wind farms.

People don’t worry about infrasound in wind, trees and ocean waves because these sources are natural, while the same levels of infrasound from wind turbines are considered quite differently as they are sourced from what anti-wind farm activists like to call evil “industrial” wind farms.

The rare examples of people complaining who host wind turbines on their land for rental payment, compared with the far more common situation of non-hosting neighbours complaining, illustrates the voluntary vs coerced exposure factor, as well as the fair vs unfair factor. Those not benefiting from lucrative rental payments because of unsuitable local topography, while near neighbours can, understandably feel this as unfair.

Wind turbines are very memorable and exotic (a new experience to many), while wind in trees or the pounding of the ocean is very familiar and unremarkable, both factors likely to greatly diminish concerns.

Table: Primary and additional components predicting community outrage about putative environmental risks to health: the case of wind turbines. (two ticks = applies strongly to wind turbines; one tick = likely to apply less strongly)

The 2015 Senate (majority) report into wind farms roundly rejected the idea that psychosocial factors such as nocebo effects were largely responsible for the challenging historical and geographical variance in wind farm complaints. A nocebo effect is the opposite to a placebo effect: instead of exposure to an inactive agent making people feel better because of belief that it will, nocebo effects are when a benign agent makes people feel worse because they have been told it will.

The Committee, chaired by avowed wind farm opponent John Madigan, was emphatic that infrasound was the culprit but did not produce convincing evidence for this.

If the committee is sincere in its concerns about the health effects of infrasound, will we soon learn of a new inquiry about the pernicious and unappreciated dangers of living near the sea or trees, having air conditioners, stereos, ceiling fans, or travelling in motor vehicles?

The Conversation

Simon Chapman, Professor of Public Health, University of Sydney

This article was originally published on The Conversation. Read the original article.

The Australian’s campaign against wind farms continues but the research doesn't stack up


Simon Chapman, University of Sydney

The Australian newspaper’s campaign against wind farms continued this morning with a page one story from the paper’s environment editor Graham Lloyd.

Lloyd writes about purportedly “groundbreaking” German research which, he infers, may provide a plausible basis for claims about wind turbines having direct effects on health.

Lloyd writes:

The results showed that humans could hear sounds of eight hertz, a whole octave lower than had been previously assumed, and that excitation of the primary auditory cortex could be detected down to this frequency.

A description of the project is here. The research never mentions wind turbines, only low-frequency noise, which is produced by many sources found in both nature and from a wide variety of mechanical sources.

The press release pitch, with its mentions of wind turbines, smells like a hook to a topical issue calculated to amplify attention to their work. (Note, this link to the press release was down at the time of publication.)

But these new findings are hardly “groundbreaking”. Earlier work found evidence of very similar auditory cortex stimulation from noise at 12Hz, slightly higher than the 8hz in this study.

In the study that excited Lloyd and the Australian’s sub-editors (the headline reads “Brains excited by wind turbines study”), auditory cortex stimulation at 8Hz (at pressure levels around the threshold of hearing) is meaningless in the context of wind turbine-generated infrasound, which is well below the threshold of perception.

Moreover, even fake stimuli can precipitate measurable activity in the brain. We know that both placebos (factors that increase expectations of positive outcomes) and nocebos (those which increase expectations of negative outcomes) can increase changes in cerebral metabolic rate when viewed via positron emission tomography (PET) scanning.

Expectations do not just affect people’s subjective experience of a stimulus (such as exposure to infrasound) but can actually produce measurable changes in brain activity which may or may not be markers of anything of clinical significance.

Fascinating work from Hungary and Germany on “electrosensitive” people (for example, those claiming to be made ill from exposure to mobile phones, wifi or other “stray” electricity) has shown that when such individuals are exposed to sham (fake) radiation from their feared source while thinking it is real, they experience symptoms. Correlates of these symptoms can be measured in the brain.

The Hungarian study exposed both people with “Idiophathic Environmental Intolerance (IEI) attributed to electromagnetic fields” and control subjects not reporting this condition to sham radiation. Those claiming IEI to electromagnetic frequency radiation both expected and experienced more symptoms.

In the German study, subjectively electrosensitive patients and gender-matched healthy controls were also exposed to sham mobile phone radiation and heat as a control condition. The subjects were not aware that the radiation was fake. Both before and during these exposures:

increased activations in anterior cingulate and insular cortex as well as fusiform gyrus were seen in the electrosensitive group compared to controls, while heat stimulation led to similar activations in both groups.

As the Hungarian researchers noted, electrosensitivity:

seems to be formed through a vicious circle of psychosocial factors, such as enhanced perception of risk and expectations, self-monitoring, somatisation and somatosensory amplification, causalization and misattribution.

In short, as the old saying goes, you can worry yourself sick. And those who spread fear arguably are an important part of this process.

Today’s Australian article complements Lloyd’s uncritical accounts of two recent studies about wind turbine noise. He wrote that:

Scientists in Japan measured brain function and reported last year that it showed the brains of Japanese wind turbine workers could not achieve a relaxed state.

As prominent wind industry science and research commentator Ketan Joshi has written:

[the study] doesn’t control for expectations, and it’s very likely that the subjects could perceive the sound = 20Hz at 92 dB(G), [at] the volume at which the synthesized noise was played, would annoy anyone.

Joshi compares such levels to the noise that would be experienced right inside a wind turbine nacelle, not hundreds of meters or several kilometers away, and notes that wind farm workers would never work inside nacelles when the turbines were turning.

Quoting an Iranian study, Lloyd continues:

In a similar vein, a study of 45 people … by Tehran University … said “despite all the good benefits of wind turbines, it can be stated that this technology has health risks for all those exposed to its sound.”

The study he referred to was of poor quality and Joshi has also mercilessly eviscerated its many problems, none of which Lloyd even hinted at.

Lloyd left messages for me to comment on the German research for his story. As his report notes, I did not respond. I have zero interest in obligingly playing into the Australian’s one-sided coverage. The paper has reported on a succession of trivial to terrible “studies” and published opinion pieces which are exalted by the tiny cells of anti-wind farm activists happy to embrace any fragment that furthers their cause.

No reporter from News has ever reported on any of my five recent studies on wind here, here, here, here, or here.

The University of Auckland’s Fiona Crichton who is arguably doing the world’s most advanced research on nocebo effects and wind farms has similarly never been reported.

The News agenda on wind energy is a travesty of good journalism.

The Conversation

Simon Chapman is Professor of Public Health at University of Sydney.

This article was originally published on The Conversation.
Read the original article.

The real science on wind farms, noise, infrasound and health


Con Doolan, UNSW Australia

In a radio interview this morning, Prime Minister Tony Abbott raised what he described as the “potential health impacts” of wind farms.

Yesterday’s article in The Australian by Liberal Democrat senator David Leyonjhelm highlighted some very good points about wind turbine noise and its effect on people living near them. People are complaining of a range of health related problems and are attributing them to wind turbines. The question is: what is the cause of these health problems?

Many blame the production of infrasound from wind turbines, yet this has not been proven to date. What is needed is new, comprehensive research to determine the true cause.

These concerns are currently being aired through a Senate Committee on wind farms and regulations, chaired by independent senator John Madigan.

Earlier this year the National Health and Medical Research Council found that there was no evidence that wind turbines directly affect health, but called for further research, particularly on the effects within 1.5 km of turbines.

I have been interested in how wind turbines produce noise, through a variety of research projects spanning several years. The most recent was an ARC Discovery project focusing on the fundamental noise-producing physics of wind turbine blades and the development of techniques to link personal annoyance with noise levels inside homes. My group and I have also investigated ways to reduce wind turbine noise by changing the shape of the blades and to steal ideas from owls, who have the ability to fly and hunt silently.

So are Leyonjhelm’s claims correct? Let’s run through them.

Claim: “Wind turbines emit infrasound and low-frequency noise.”

Wind turbines undoubtedly create infrasound. It is created by the movement of the blades through the air, as the blades pass the tower and, depending on the construction of the turbine, by the gearbox.

Claim: “Inappropriate levels of infrasound, regardless of the source, cause adverse health impacts.”

However, most experts believe that the level of infrasound produced by wind turbines is too low to be heard or create health problems. Recent measurements show that infrasound can propagate many kilometres from a wind farm – what we don’t know is if these very low level sounds can cause health effects.

Previous studies on the effects of infrasound on health have focused on the exposure of high levels of infrasound from industrial sources. These studies show that perception or physiological effects occur at levels that are many times those generated by wind farms.

Claim: “Research by NASA … established wind turbines could generate surprisingly high levels of infrasound and low frequency noise.”

While it is true that early designs of wind turbines created large amounts of low-frequency noise that was annoying (the so-called “downwind” turbines of the 1980s which were reported on by NASA), modern designs that place the rotors upwind of the tower have greatly reduced this problem and made wind turbines quiet enough for widespread use.

There have also been many years of intensive research and development into the design of quiet wind turbine rotors and operational methods to reduce noise. This is not to say that wind farm noise is not responsible for reported health problems.

The effect of sensitization after long exposure to low-level noise, the effects on sleep and the role of moderating factors must be considered along with noise generation and propagation effects to properly understand why so many people are complaining of health problems near wind farms.

Claim: “Wind farms are not required to limit or even monitor their infrasound emissions.”

There are no requirements for infrasound to be monitored near wind farms because it occurs at a very low level and is not expected to be heard by most people. It is also very difficult to measure, especially in the presence of wind that will also generate infrasound of the same or higher level when it passes through trees or blows over a house.

Even when we do record it, we don’t yet know what level is responsible for causing health problems.

What is needed is new multi-disciplinary research linking engineers with medical and health scientists where noise data and health information are recorded simultaneously for people living close to and far from wind farms. Only such detailed research can help provide an answer to this challenging and perplexing problem.

The Conversation

Con Doolan is Associate Professor, School of Mechanical and Manufacturing Engineering at UNSW Australia.

This article was originally published on The Conversation.
Read the original article.

Australia: Victoria and Wind Farms


The link below is to an article reporting on wind farms in the Australian state of Victoria.

For more visit:
http://www.guardian.co.uk/environment/southern-crossroads/2013/may/29/1