Sunday explainer: Do wind turbines harm your health? 

The issue of whether wind turbines – one of Australia’s largest clean energy sources – cause health problems has again reared its head. Tom Arup explains why turbines take the wind out of some people’s sails.

What prompted the latest claims that wind turbines cause health problems?

A new study looks at the reactions of six residents to the noise from the Cape Bridgewater wind farm, in south-west Victoria.

The study was ordered by wind farm owner Pacific Hydro to examine whether there is a link between the noise and ongoing health complaints made by the six residents, who all live within 1.6 kilometres of turbines.

It was conducted by acoustic engineer, Steven Cooper, who installed sound detection equipment in three homes and at the wind farm. Data was collected over eight weeks under different wind conditions, and when the turbines were shut down.

The residents were asked to record in a diary any feelings of noise, vibrations and “sensations”, such as headaches, pressure in the head, ear or chest, ringing in the ears, a racing heart or a sensation of heaviness.

What does the report say?

It found sensations were the “major form of disturbance from the wind farm” recorded by the subjects, ahead of noise and vibrations.

Mr Cooper also says he discovered a special “noise signature” produced by the turbines. The signature was infrasound – noise at a lower frequency than humans can hear.

The report finds a correlation between residents feeling sensations of high severity and certain turbine operations, such as powering up or down significantly. But there are caveats, explicit and not.

It says there is not enough data to justify changing regulations. And one resident recorded feeling sensations when the turbines were not operating.

The report also says it was “outside the limits of the team’s expertise” to determine whether the infrasound triggered responses in residents. It suggested this should be considered in future medical studies.

Some observers have pointed out the report excludes from analysis 50 of the 81 recorded instances of the highest severity sensations (ranked by residents 5 out of 5). It also excluded 323 sensations ranked 4 out of 5 for severity, because the time involved “would be significant”.

What has the reaction been?

Almost immediately there was criticism from some scientists and the wind power industry.

Writing in The Conversation, two researchers from the Australian National University National Centre for the Public Awareness of Science labelled the study an “exemplary case of what we consider to be bad science”. They said it had a tiny sample size, included only people already unfavourably disposed to the wind farm and did not have a control group. Others stressed that it had not been peer-reviewed.

Pacific Hydro said it did not believe the narrow band of data used by Mr Cooper supported his strong conclusions. Clean Energy Council director of policy Russell Marsh questioned Mr Cooper’s objectivity, pointing to his past work with wind farm opponents.

The residents involved in the study released a statement via the website of an anti-wind farm organisation, the Waubra Foundation, saying the findings meant Cape Bridgewater should be declared a “hazard to human health”.

What has other research looking at the health impact of wind turbines found?

So far, not a lot.

In a review of published scientific research, the National Health and Medical Research Council last year concluded there was no reliable or consistent evidence wind farms caused health problems. It did find some consistent, albeit poor, evidence that living close to turbines was associated with annoyance, but did not conclude it caused annoyance.

The federal government has now asked the council to do further research. The council is planning to fund new studies after identifying “knowledge gaps”.

Perhaps the most comprehensive study in recent times has come from Canada’s national health department. It involved 1200 residents living near turbines across two provinces, and found no evidence of a link between turbine noise and poor health. It did find a relationship between noise and annoyance.

Have there been complaints about wind turbines affecting health in other countries?

Yes. Similar health complaints in developed countries such as Britain, the United States and Canada. But it is difficult to quantify exactly how many complaints there have been. Most researchers accept that some are genuinely experiencing symptoms, but peer-reviewed scientific studies have not linked them to turbine noise.

How many wind turbines are there in Australia?

Australia has had commercial wind farms since 1987, but their footprint has expanded significant since the 2000s on the back of federal government support for renewable energy.

At the end of last year there were 1866 turbines installed in 71 projects, with another five wind farms under construction. In 2013, wind energy produced 9259 gigawatt-hours of electricity across the country.

But their expansion has now slowed. Australian renewables investment collapsed in 2014. Market analysts blame the uncertainty created by the breakdown in bipartisan support for the national renewable energy target.