Wind Farm Noise: Industry Admission of a Problem

Written by PSI Staff

What is an appropriate and safe noise level for wind turbines? Well, based on the latest revelation from the wind industry itself, it appears that a stricter noise limit is long overdue. This is because the impacts on human health may be shown to be more serious than previously believed (or acknowledged!).

wind turbine noise

Principia Scientific International releases the latest on this in an email from acoustician, Mike Stigwood (below):

Wind Farm – Amplitude Modulation controls finally accepted at 3dB

Dear all, 

Recent research presented at three Planning Inquiries that were conducted in September, October and November (Starbold, Bryn Lleweln and Shipdham – decisions awaited)  have hopefully exposed the misconceived arguments made by the Industry’s acousticians’ which have successfully avoided controls over wind farm noise impact for many years.      

After more than 4 years of smoke screens, obfuscation and erroneous objections raising unrealistic concerns and placing barriers in the way of necessary controls over the wind farm noise called “Excess Amplitude Modulation”, industry acousticians have finally admitted a planning condition is ” necessary” and “reasonable”.

Excess AM is now shown to be neither rare nor only causing minor effects as claimed over the last few years, arguments that have successfully blocked planning controls leaving many communities exposed to serious noise impact.  Research by ourselves and the Japanese have exposed this as a common and serious problem.  Dr Matthew Cand of Hoare Lea is part of the Renewables UK research team on EAM who were due to report their findings over 2 years ago but have continuously deferred this.  He finally admitted after 2 hours of cross-examination, when being questioned over the need for a condition at the Shipdham Inquiry last week, that one was both necessary and reasonable.  Dr Cand was also questioned over the Den Brook condition metric which was accepted in 2009 but rejected ever since and that was formulated by MAS Environmental with a 3dB(A) EAM limit.  

This has been subject to widespread industry attacks over the last four years, leading to its rejection by planning inspectors ever since the Den Brook decision.  In response Dr Cand said “If I had to pick a number I don’t think 3dB(A) is a bad number”.  In effect the Renewables UK research must support what we found four years ago.   These admissions follow years of unpublished work by Renewables UK, coupled with statements that no one knows the appropriate level.  

 In September at the Starbold Inquiry arguments that the Den Brook condition was triggered by extraneous noise were dropped by the appellants and they accepted it was an incorrect argument.  Following the Bryn Llewelyn appeal in October 2013 Dr Jeremy Bass of RES, the main opponent of the Den Brook condition said during a meeting: “foolishly … we went along the industry line that amplitude modulation is rare”.    

He accepted the argument that it can be dealt with by statutory nuisance was wrong.  He continued “I think that argument is completely exploded by the weight of evidence presented by Mike Stigwood in particular …. we are in a difficult position now … the landscape has changed and I suspect …. in the future developers will no longer try the argument that AM is rare”.
 It is hoped decision makers will no longer receive erroneous arguments about the control of EAM and that conditions following the Den Brook metric are now applied to all future consents.  There also needs to be a mechanism developed by Government for applying it to existing wind farms.  Emerging evidence from the Japanese studies suggests a stricter limit may arguably be necessary but at the present time it is safe to consider the Den Brook metric as a means of controlling wind farm noise.   We also hope decision makers will now exercise particular caution with respect to arguments made by wind industry acousticians and that those who raise concerns over wind farm noise, in the main, do so legitimately.      

If anyone seeks further information on appropriate forms of control of this common noise problem they can visit our website at <>  for more information or email us direct. 

Kind regards 
Mike Stigwood

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     If anyone seeks further information on appropriate forms of control of this common noise problem they can visit our website at   for more information or email us direct.  

     Kind regards 
    Mike Stigwood

Comments are closed