“Tonight, for the first time, hard evidence that wind farms are not safe,” stated the introduction to one current affairs program in Adelaide in February 2015.
“I’m not telling furphies,” one resident who lived near a wind farm in South Australia exclaimed on the program. “It’s real. We can feel it.”
Even the chickens, the program asserted, were being spooked by the turbines. It showed an egg being broken which appeared to be lacking in yolk – a problem the program attributed to the nearby turbines.
That program followed a front page headline in a major newspaper in January that year about a ‘ground-breaking’ study undertaken by acoustic engineer Steve Cooper and commissioned by Pacific Hydro. The opening paragraph of that study claimed, found that “people living near wind farms face a greater risk of health complaints caused by the low-frequency noise generated by the turbines.”
As the ABC’s Media Watch pointed out, however, these claims were problematic. The study which offered the so-called ‘proof’ had been neither peer reviewed nor published in any academic journal. Its sample size was miniscule – six participants across three households. In addition, there was what is known as ‘selection bias.’ Each of the participants had health problems which they had blamed on Pacific Hydro’s wind farms at Victoria’s Cape Bridgwater. All could see the blades from their home and thus knew whether or not the turbines were operating.
Cooper, the study’s author, acknowledged that it was incorrect to hold out the results of the study as conclusive evidence about the health impacts of wind farms. Pacific Hydro said the study was neither a scientific study nor a health study and did not show that wind farms were causing health complaints.
Both internationally and in Australia, the prevalence of wind farms is growing amid a push toward cleaner forms of energy. Over the four years from December 2013 to December 2017, the installed capacity of wind energy generation worldwide grew from 318,577 megawatts to 539,291 megawatts according to the World Wind Energy Association. This represents an increase of almost 70 per cent. Over that time, capacity in Australia increased by 60 per cent from 3,049 megawatts to 4,879 megawatts.
As this has occurred, claims about health impacts from wind turbines have been made. Through various effects relating to acoustics, visual impacts and electromagnetic emissions, a spectrum of disorders have been claimed to occur among those who live in proximity to wind farms. These include sleep loss, fatigue, nausea, headaches, disturbance of balance, dizziness, stress, depression, irritability, anxiety, perturbed steroid hormone secretion, hypertension and socio-behavioural changes.
One key concern is infrasound: energy which appears in the spectrum which is below what the human ear can normally hear. This, according to some claims, can interfere with sleep and brain patterns.
All this raises questions about whether such claims hold water.
Primarily because of a lack of quality data, evidence to date is inconclusive.
Several years ago, the National Health and Medical Research Commission (NHMRC) undertook a comprehensive assessment of the evidence on the possible effects of wind farms in humans. Its final report in 2015 found that:
- there was no direct evidence that exposure to wind farm noise affects physical or mental health
- there was consistent but poor quality direct evidence that wind farm noise is associated with annoyance
- there was less consistent and poor quality direct evidence of an association between sleep disturbance and wind farm noise
- there was no direct evidence that considered the possible effects on health of infrasound or low frequency noise from wind farms.
Overall, that review found there was no consistent evidence that wind farms cause adverse health effects in people, although it acknowledged that more research was needed.
“After careful consideration and deliberation of the body of evidence, NHMRC concludes that there is currently no consistent evidence that wind farms cause adverse health effects in humans,” the Commission said in its report.
“Given the poor quality of current direct evidence and the concern expressed by some members of the community, high quality research into possible health effects of wind farms, particularly within 1,500 metres (m), is warranted.”
Another study in Canada undertaken by Health Canada looked at randomly selected participants across the provinces of Ontario and Prince Edward Island who lived varying distances from wind turbines. It involved an in-person questionnaire; collection of objectively measured outcomes that assessed hair cortisol, blood pressure and sleep quality; and more than 4,000 hours of wind turbine noise measurements.
According to that study, there was no correlation found between wind turbine noise and self-reported levels of sleep, illness, chronic disease, stress or quality of life. Nor was there any significant correlation between wind turbine noise and sleep found in objectively measured results. There was, however, a statistically significant relationship between wind turbine noise and the level of annoyance which residents felt at higher levels of wind turbine noise.
Locally, an independent report released on September 13th found that noise from the Bald Hills Wind Farm in Victoria’s Gippsland region was impacting the comfort of local residents – and potentially, their well-being. That report followed a ‘nuisance’ complaint from a resident about two years ago under the Public Health and Wellbeing Act.
In respect of sleep disturbance, much light will hopefully be shed on this as a result of a five-year Wind Farm Noise Study which is currently being undertaken by South Australia’s Flinders University. The study involves a survey of people exposed to wind farm or traffic noise; an in-home sleep and noise study of people who are affected by noise; and a laboratory study to investigate noise effects on sleep in a controlled sleep and noise environment.
In an interview, professor Peter Catcheside from the University’s Adelaide Institute for Sleep Health told Sourceable there was a lack of quality evidence to support or refute claims about public health effects of wind turbines.
According to Catcheside, there have been relatively few studies investigating noise and noise impacts associated with wind turbines. Most notably, these include the Health Canada study, some smaller observational field studies and some laboratory based experiments of noise annoyance and sleep disturbance.
To date, Catcheside says the most consistent findings to date appear to relate to noise annoyance. However, he cautions that direct causal relationships between noise and potential health impacts cannot be established from observational studies alone, which requires carefully controlled studies.
Thus, he says currently available evidence remains too limited to draw firm conclusions regarding potential health impacts. Because transport related noise impacts on sleep are well known, he says sleep disturbance is one of the main plausible mechanisms of potential health impacts. Thus he says this area warrants careful consideration.
Catcheside cautions that the Canadian study is not sufficient to rule out potential sleep disturbance impacts. There are two reasons for this.
First, sleep was not measured directly. Instead, the researchers used a device to measure movement versus inactivity to infer wake compared to sleep. This, Catcheside caution can only provide an approximate estimate of sleep quality.
Second, noise was primarily assessed on the basis of noise modelling rather than direct noise measurements.
As a result, he says care should be observed in drawing firm conclusions from this study.
“It’s an interesting question and a very murky area,” Catcheside said, asked whether claims are supported by facts.
“The bottom line is that there is no good quality evidence to either support or refute claims of adverse health effects. The quality of available evidence is poor.
“Our project is focussed mainly around a carefully controlled laboratory study aiming to help address legitimate unanswered questions around potential sleep disturbance effects.”
According to Catcheside, several areas warrant consideration.
One is the low-frequency nature of noise emitted by wind turbines. Unlike high frequency noise, Catcheside says low frequency noise travels longer distances, penetrates into buildings more readily, and is less easily masked by background noise in a typical rural setting.
Depending on noise sensitivity and other factors, Catcheside says low-frequency noise could potentially be troublesome to some.
In addition, Catcheside says an important feature of wind farm noise may be its pulsating nature. This is associated with blade-tower interactions and other aerodynamic effects giving rise to time-varying amplitude modulation, making the noise become louder or softer around once every second.
Catcheside says there are also issues with how noise is measured. On this score, he says the dBA weighting which is conventionally used to measure sound scales everything to a linear function of average human hearing. This could be problematic for low-frequency noise as hearing at the low end is particularly variable and apparent loudness is not linear. Thus he says some elements of low frequency noise can be audible to some yet not to others, although he stresses that a substantial part of the noise spectrum should be audible to most people.
Overall, if there are health related impacts from wind turbines, Catcheside suggests one of the most likely mechanisms could be through noise related sleep disturbance. Thus the Flinders University study is looking into direct measurements of brain activity during sleep with and without exposure noises of different types (wind farm and traffic noises) and sound pressure levels to establish their relative ‘dose-response’ relationships; using conventional dBA and other noise assessment methods.
Other researchers are less charitable about the quality of evidence put forward in support of wind farms’ claimed health impacts. In their 2017 book Wind Turbine Syndrome: A Communicated Disease, University of Sydney Emeritus Professor Simon Chapman and University of Auckland PhD Candidate Fiona Crichton are scathing about the claims of those who oppose wind farms and the evidence put forward to support those claims.
Some studies used to support wind farm opposition, Chapman and Crichton say, are ‘appallingly inept and pointing out their many weaknesses may appear cruel.’
Around Australia, the number of wind farms are growing.
Thus far, the jury remains out on their potential health impacts.