Campaigners have called for more research into the health impact of wind turbines after researchers discovered what they believe is a link to epileptic fits.
Academics at the universities of Essex and Aston concluded blades should not rotate more then 60 times per minute, or they could endanger sufferers of photosynthetic epilepsy.They concluded the “flicker” effect of rotating blades could bring on seizures up to around 4km away – 100 times the height of the average turbine.
A spokesman for the team, headed by Professor Arnold Wilkins, said: “Turbines that rotate faster or have more blades will produce unacceptable levels of flicker.
“Smaller variable-speed turbines range between 30 and 300 revolutions a minute and some have more than three blades, so their flicker is within the range for which seizures are likely.”
She said researchers were seeking to identify what type of flicker from wind turbines could bring on seizures and as a result have come up with guidelines to minimise impact.
“Planning permission for wind farms often consider flicker, but current guidelines relate to annoyance and are based on physical or engineering considerations rather than the danger to people who may be photosensitive,” she said.
Gary Watson, chairman of the Buckland-tout-Saints residents’ association, which is opposing plans for three turbines at Goveton, near Kingsbridge in South Devon, said it was extremely difficult to have applications rejected on the grounds of health concerns.
Dr John Constable, director of policy and research with the Renewable Energy Foundation, said many reports so far had related to noise disturbance, adding: “Whether there are also health problems, it’s really difficult to tell. I know people who are world leaders in this field and they assure me we don’t know what the problems are surrounding turbines.”
Bob Morgan, of Cornwall Light and Power, said the findings only related to small domestic turbines. He said: “Commercial wind turbines nowadays rotate at around 30 to 60rpm. That’s well below the figures at which epilepsy is instigated. The concerns with wind turbines are over domestic turbines. They have small blades, and rotate at faster speeds.”
Simon Holt, renewables developer with npower, which is awaiting a decision on plans for a wind farm at Batsworthy Cross, North Devon, said proposed turbines would rotate at “much less” than the level cited as a concern by researchers. He said: “Where deemed appropriate, control systems can be utilised to prevent the occurrence of shadow flicker from wind farms where it has potential to cause annoyance.”
A spokesman for the Department for Business, Enterprise and Regulatory Reform, said: “Shadow flicker is an issue of which the Government is aware and is considered during the planning consent process. We have been advised problems caused by shadow flicker are rare. The Health and Safety Executive (HSE) advises a flicker rate fewer than five flickers per second may help to avoid health problems. We expect developers to follow these HSE guidelines.”
6 May 2008
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