A Government study into the noise effects of wind farms has been described as a ‘disgrace’ because it fails to take into account the problem of sleep deprivation and other health issues.
The Institute of Acoustics has been asked to draft new guidance for planners and developers on how to check noise levels around new wind farms.
The document, to be issued early next year, will advise on the best way to measure noise and may result in less wind farms being built in the wrong places.
However independent acousticians have criticised the Government’s failure to look at the latest evidence on health or consider lowering the limit on noise levels, especially at night.
Dick Bowdler, a member of the IOU who is not involved in the study, said noise level limits and health effects should have been taken into account as part of the new guidance.
The acoustics consultant pointed out that this is not only essential for planning a wind farm, but for compensation if it is built.
It is also important for working out the cumulative effect from other wind farms in the area.
He pointed out that terms of reference of the study was dictated by the Department of Energy and Climate Change (DECC), who also largely funded the study.
“Not being able to discuss limits does not only affect discussion of the limits per se but shackles proper discussion on other matters – such as World Health Organisation guidance, choice of day lime limit, advice on financial involvement and cumulative noise issues,” he wrote in an official response to consultation on the guidance.
At the moment wind farms are not supposed to be built if assessments predict noise levels above 40 decibels (dB) during the day and 43db at night.
Mr Bowdler said this is potentially too high for people living within 1.5km of the turbines because of the risk of sleep disturbance and other problems.
He said the guidance could even lead to higher levels of noise, as “unscrupulous” developers will build at the edge of the limit.
“The institute will be seen as the organisation that raised wind farm noise limits,” he warned.
Richard Cox, a retired electrical engineer who recently wrote a paper on the noise effects of wind farms with the help of the Tory MP Chris Heaton Harris, pointed out most of the panel working on the guidance made their living from wind developers.
“Being expected to conduct a review of wind turbine noise assessment guidance, effectively to rubber stamp DECC policy without being able to consider noise limits or the health effects of the noise or even amplitude modulation is farcical and totally unacceptable for a scientific body,” he said.
Dr Lee Moroney, planning director for charity the Renewable Energy Foundation, said the issue of low frequency noise and the swishing of the blades (also known as amplitude modulation) was not taken into account sufficiently.
She was also angry that the higher level for night time noise has not been questioned.
“It is a disgrace that DECC, the department responsible for promoting wind farms, is permitted to set the noise limits for wind farms whereas other environmental noise limits are set by DEFRA. It is also a disgrace that a professional body such as the Institute of Acoustics agreed to carry out an independent evaluation of wind farm noise practices but agreed to DECC’s condition not to question whether wind farm noise limits are too high or that it is reasonable for wind farm noise to be permitted to be louder during the night than during the day.”
Richard Perkins, Vice President of the Institute of Acoustics and chairman of the working group looking at the guidance, insisted the new guidance would tighten up the rules so that only wind farms in the right places are given planning permission.
He said current noise levels are a matter for the Government, and were outside the working group’s terms of reference.
He insisted consultation feedback from respondents on noise limits would be fed back separately to the Government.
He pointed out that technology and understanding of the noise affects around wind farms have improved in recent years so the new guidance will be better able to ensure noise is kept within a safe limit.
“We are making sure that the wind farms that do go ahead are appropriately sited and minimise the impact on local people – it may rule some out.”
Renewable UK, the wind industry group, are currently investigating the issue of amplitude modulation.