A comprehensive study by Salford University has concluded that the noise phenomenon known as aerodynamic modulation (AM) is not an issue for the UK’s wind farm fleet.
AM indicates aerodynamic noise from wind turbines that is greater than the normal degree of regular fluctuation of blade swoosh. It is sometimes described as sounding like a distant train or distant piling operation.
The Government commissioned work assessed 133 operational wind projects across Britain and found that although the occurrence of AM cannot be fully predicted, the incidence of it from operational turbines is low.
Commentating on wind farm worries, Energy Minister Malcolm Wicks said:
“Where there are legitimate problems we will address them. But it is essential that we produce more wind power if we are to meet our climate change and security of supply aims.”
Out of all the working wind farms at the time of the study, there were four cases where AM appeared to be a factor. Complaints have subsided for three out of these four sites, in one case as a result of remedial treatment in the form of a wind turbine control system. In the remaining case, which is a recent installation, investigations are ongoing.
Based on these findings, Government does not consider there to be a compelling case for more work into AM and will not carry out any further research at this time; however it will continue to keep the issue under review.
Notes to Editors
1. The Research into aerodynamic modulation of wind turbine noise – Report by the University of Salford was jointly commissioned by three government departments, BERR, DCLG and Defra. For a full copy click here: http://www.berr.gov.uk/files/file40570.pdf
University of Salford, Research into Aerodynamic Modulation of Wind Turbine Noise
Government statement regarding the findings of the Salford University report into Aerodynamic Modulation of Wind Turbine Noise
In 2006 DTI (now BERR) published a study by Hayes McKenzie1 which investigated claims that infrasound or low frequency noise emitted by wind turbine generators was causing health effects. The report concluded that there is no evidence of health effects arising from infrasound or low frequency noise generated by wind turbines. The report went on to note that a phenomenon known as Aerodynamic Modulation (AM) was in some isolated circumstances occurring in ways not anticipated by ETSU-R-972.
Having taken the view that more work was required to determine whether or not AM is an issue which may require attention in the context of the assessment and rating advice in ETSU, the Government commissioned Salford University to conduct a further work.
The objectives of this study were to:
* To establish the levels and nature of the reported noise complaints received across the UK relating to noise issues from wind farms, both historic and current, and determine whether AM is a significant effect;
* To review and understand the level of knowledge/understanding that exists throughout the world on AM, and whether AM can be predicted;
The Salford University study has now been published3. The study concluded that although AM cannot be fully predicted, the incidence of AM resulting from wind farms in the UK is low. Out of the 133 wind farms in operation at the time of the study, there were four cases where AM appeared to be a factor. Complaints have subsided for three out of these four sites, in one case as a result of remedial treatment in the form of a wind turbine control system. In the remaining case, which is a recent installation, investigations are ongoing.
Based on these findings, Government does not consider there to be a compelling case for further work into AM and will not carry out any further research at this time; however it will continue to keep the issue under review.
Government continues to support the approach set out in Planning Policy Statement (PPS) 22 – Renewable Energy. This approach is for local planning authorities to “ensure that renewable energy developments have been located and designed in such a way to minimise increases in ambient noise levels”, through the use of the 1997 report by ETSU to assess and rate noise from wind energy developments.
2. For a copy of the report click here: http://www.dti.gov.uk/energy/sources/renewables/publications/page31267.html
3. The method of assessing the impact of the wind farm locally is described in ‘The assessment and rating of noise from wind farms’, ETSU-R-97, by the Working Group on Noise from Wind Turbines (Final Report, September 1996). Since its publication, this report has been used to evaluate the noise from wind farms in the UK.
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