Noise from Wind Farms
Noise from onshore wind farms in the UK is assessed in accordance with the Department of Trade and Industry publication ETSU-R-97 ‘The Assessment and Rating of Noise from Windfarms’ (ETSU). The recent Institute of Acoustics’ publication ‘A Good Practice Guide to The Application of ETSU-R-97 to the Assessment and Rating of Wind Turbine Noise’ has been fully endorsed by the UK document and is as important in planning terms as ETSU-R-97. The Good Practice Guide provides clarity on the use of ETSU and has removed some of the uncertainty and potential for technical dispute relating to wind farm/ turbine noise impact assessment.
ETSU defines minimum day-time and night-time absolute noise limits (unrelated to background noise levels) and an assessment methodology relative to the background noise level (whichever is greater). As the noise level emitted from wind turbines varies according to wind speed it is necessary to measure the background noise level at each receptor over a range of wind speeds and assess the noise impact over the range of operational wind speeds of the turbines.
The use of ETSU is becoming increasingly criticised as it offers the potential for a severe noise impact to occur, particularly in areas which are subject to low background noise levels and particularly at night. The Planning Inspectorate are increasingly aware of this issue and a recent and potential landmark decision (October 2013) dismissed an appeal, partially on noise grounds, although the site was compliant with the ETSU noise limits.
At 24 Acoustics we work on projects of all sizes on sites throughout the UK (and beyond). We take a balanced and consistent approach to our assessments, regardless of who we are employed by (which includes wind turbine developers/ energy companies, local planning authorities, local residents and wind turbine manufacturers.