Wind turbine noise is not a health hazard
One of the world’s foremost acoustic engineering experts has rubbished claims that noise from wind turbines can cause health problems. However, he believes that noise annoyance is being used as an excuse to spread alarm and increase opposition to wind power.
Former Institute of Acoustics president Geoff Leventhall told a recent meeting of the CIBSE/ASHRAE Group at London South Bank University that turbines can cause “annoyance”, which could be linked to stress, but that there was no evidence to suggest noise from wind farms was directly linked to physical health problems.
Professor Leventhall has been involved as an expert witness in a number of legal cases where ‘victims’ have made claims about harm caused by low frequency infrasound waves from wind turbines. In one case in the US, the claimant said infrasound caused vibrations in the human diaphragm sending confusing signals to internal organs.
“This is simply not true,” said Professor Leventhall. “Some people have set out to create alarm by saying that infrasound is dangerous and can cause something called ‘Wind Turbine Syndrome’. The symptoms of this are psychological rather than physiological.”
Professor Leventhall explained that people’s response to noise was often conditioned by their attitude to the source and adverse publicity about wind farms had prejudiced some people against them. He added that stress can be caused by being forced to listen to a noise for extended periods and that aerodynamic noise can fluctuate, which can be irritating.
To avoid creating annoyance, wind turbines should be placed at a sensible distance from homes, added Professor Leventhall. He said that the rule of thumb was that the distance of the turbine from the nearest inhabitation should be four times its height. However, in the US homes are often closer than that. Also, the sound level from turbines permitted in UK homes was 40dBA, but in the US they allow 50dBA and “that has caused some problems”, according to Professor Leventhall.
Campaigners
In some parts of the US, turbines are only 300 metres from houses and noise levels have been measured over 50dBA and this has prompted campaigners to call for a change in the law. Most UK planners insist on a distance of 400m to 500m between houses and turbines.
“I think US legislators accept that in many cases the turbines are too close to homes, but publically they deny there is a problem,” said Professor Leventhall. “There isn’t a health problem, but noise is increasing opposition to wind energy.”
The importance of solving this problem has been highlighted by a recent issue of Scientific American magazine, the highly influential publication, which has stressed the importance of wind energy in the future mix of power generation. It estimates that the world will need to build 3.8 million 5 megawatt wind turbines to meet 51 per cent of its future energy needs.
Offshore
Professor Leventhall believes the bulk of these should be built offshore both to increase the amount of wind power available and to avoid difficulties with noise objectors. Planning permission is also proving to be a barrier in the UK with only 25 per cent of applications for wind developments being approved on first application.
“Often local authorities block the development to avoid taking flak from local residents, but safe in the knowledge that it will be approved on appeal,” he said.
Tim Dwyer, chairman of the CIBSE/ASHRAE Group, added that the experience of the US would be very helpful to the UK in dealing with some of the “unscientific theories” being put forward by objectors to the development of wind farms.
This debate comes just as UK housing minister John Healey has announced plans to relax planning laws to make it easier for building owners to erect wind turbines close to their properties.
He wants more on-site renewable developments to go ahead without the need for planning permission, but noise levels will be restricted to a maximum of 45dBA. Wind turbines up to 15m in height would be permitted in industrial parks and in remote areas where they would not disturb residents.
The Government is now embarking on a three-month consultation on the new planning proposals and M&E Sustainability will be keeping a close eye on developments.