The issue of noise produced by wind turbines is controversial. There are widely conflicting views, an apparent shortage of scientific research and planning regulations which are based on outdated data.
It seems that no one can be certain exactly what the noise implications would be until the site is operational. By then it would be too late to do anything about it.
Wind turbines produce three types of sound - (a) mechanical noise from the gearbox and generators, (b) aerodynamic noise from the movement of the blades through the air and (c) low frequency infrasound. Research has shown that low frequency sound can cause serious health problems for people sensitive to its effects. People living near wind turbines have been reported to experience health problems including sleep difficulties, headaches, irritability and stress.
1. Obviously, the closer to a turbine you live the greater the chance of noise being an issue. The nearest house to one of the proposed turbines would be around 600m.
2. Noise would vary depending on the force and direction of the wind. If the wind were from the North then Bythorn would be down-wind and one would expect any noise to carry more in that direction.
3. Different people have different sensitivities to noise.
4. Turbines can have an effect on one another. Sound waves from one turbine can affect and be affected by sound waves from others. There is potential for small "ripples" of sound from different turbines to build up into much larger "waves" of sound. This effect can become marked at certain distances from turbine clusters.
5. The wind can blow hard at any time of day or night. In the middle of the night when background noise is low the turbines could often be at their noisiest.
6. There has been little research into the noise impacts of larger (125/130m) turbines. The people with the money to undertake such research are the Government and the wind farm developers - one suspects that they have nothing to gain and everything to lose from such research.
The statutory methodology (ETSU-R-97) used by planning authorities to assess wind farm noise was developed back in 1996 using data from turbines only 40m to 60m high.
Professor Ffowcs-Williams, Emeritus Professor of Engineering, Cambridge University, one of the UK’s leading acoustical experts has said:
"The regulations (ETSU-R-97) are dated and in other ways inadequate. It is known that modern, very tall turbines, do cause problems, and many think that the current guidelines fail adequately to protect the public."
[source - Renewable Energy Foundation (REF) - Press Release 4/8/2005 - "Studies on Wind Turbines Noise Raise Further Concerns" - August 2005] - this document is no longer availabe online.
Thus the fact that any proposed wind farm appears to comply with ETSU-R-97 in an Environmental Impact Assessment gives no guarantee that there will be no noise problems for people living in the area once the wind farm is built.
Reports from the UK Noise Association and others suggest that the harmful effects on the health of people living near to wind turbines are insufficiently assessed and that minimum separation of wind turbines from dwellings needs to be increased (recommendations range from 1.5km to 1.5 miles), particularly for the large, modern turbines, until comprehensive scientific research can fully evaluate their impact.
Noise specialist, Mike Barnard observes:
"There have been many examples in the past when warning signs of future problems with new technologies have been overlooked or ignored (e.g. asbestos/tobacco). It took time before a pattern of health complaints were observed. As turbines increase both in size and proximity to houses reports of health effects appear to have started to escalate. In years to come the noise issue from large modern turbines may be seen to have fallen into the same category."
Experience of noise
Finally, the experience of the Davis family from Deeping St Nicholas, who live 930m from an eight turbine wind farm, makes worrying reading. As soon as this wind farm became operational in 2007 they started experiencing noise problems which reached such a state that they have had to find an alternative "sleeping house" 5 miles away in order to get an uninterrupted night’s sleep. Yet the wind farm met the Government guidelines. See: "Statement from Jane Davis of Deeping St. Nicholas" - National Wind Watch online documents - April 2007.
Lynn Hancock, who lives near the Red Tile wind farm north of Cambridge says:
"Imagine a seven-ton lorry left running on the drive all night and that’s what it’s like. People describe it as like an aeroplane or a helicopter or a train that never arrives. It’s like it’s coming but it never gets here.” - Officials Cover Up Wind Farm Noise Report, The Times 13 December 2009.
There is a proposal by Npower to build a wind farm at Bradwell-on-Sea near Maldon. This is subject to a public enquiry following various appeals. Most relevant here is the rebuttal of evidence adduced by Npower regarding noise, which can be viewed here.
For an interesting TV broadcast on the effects of wind turbines on local residents - especially the noise - see the LBV Television programme available on Google videos.According to the Daily Telegraph, there have been complaints about noise in relation to as many as 1 in 6 wind farms.
For Plymouth GP Dr Amanda Harry's report on Wind Turbines, Noise and Health, click here.
For information on the risk of ice-throw, see:
Risk Analysis of Ice Throw from Wind Turbines (MSUE website)
There are many horses within 1km of the turbines and riders are a daily feature of local roads and bridleways. Sun flickering on metal rotors can easily "spook" a horse - with potentially dangerous consequences for riders and other road users.
Flicker is also likely to affect local residents, especially those in Molesworth village as the sun is setting in the mid- summer months. It is possible that turbines 7 and 8 will overlap, creating an even more strobe-like effect on occasion. Bythorn may be similarly afflicted over the same one to two month period by sunrise. There may be slight flicker effect at sunrise on the A14.
The energy company will only be concerned to limit flicker through windows - possibly by providiing blinds - within a certain range of the turbines. They will not be concerned about flicker across gardens. Within a specified range of the turbines, they do have to be turned off at sunset to prevent flicker, but this is likely to be just short of Molesworth village.
At night the pulsing red warning lights on the back of each turbine can also cause flicker, as they are reflected off the turning blades.For information on the effects of sun flicker on epilepsy, click here.
For a summary by The Energy Workshop, click here.
GE Energy report Ice Shedding and Ice Throw – Risk and Mitigation
For links to several articles on health issues related to wind farms see Views of Scotland.