3 February 2022
ATISN – 15740 Wind Farm and Dwelling Separation Distances
Thank you for your request which was received on 2 December 2021. You asked:
On what published scientific evidence did the Welsh Government arrive at a minimum separation distance of 500 metres between a wind turbine and a domestic property?
Following a search of our paper and electronic records, I have established that the information you require is not held by the Welsh Government.
Informative Note on Welsh Government’s Position on Separation Distances
The Welsh Government requires separation distances to be determined locally based upon the rigorous assessment of local impacts. The Welsh Government believes that a rigid minimum separation distance could unnecessarily hinder the development of renewable energy projects in Wales. We have taken the consistent view that the issue of separation distances between residential premises and wind turbines is best determined locally on a case-by-case basis, taking on board locally sensitive issues such as topography, local wind speeds and directions as well as the important considerations of visual, cumulative and other impacts.
The Welsh Government procured research from Arup in 2002 to establish the boundaries of Strategic Search Areas for large scale wind energy development in Wales. This culminated in a final Arup report ‘Facilitating Planning for Renewable Energy in Wales: Meeting the Target’ in 2004. In this report Arup suggested 500m as a typical buffer between wind turbines and residential dwellings to mitigate noise, amenity and safety issues. Arup indicated that this buffer was based on emerging best practice within the industry at the time (see appendix 1 for relevant excerpt from report).
Technical Advice Note 8 Planning for Renewable Energy (now revoked), which was published in 2005, took the view that whilst 500m was considered the typical buffer between residential dwellings and wind turbines to avoid unacceptable impacts from noise, when applied in a rigid manner it can lead to conservative results and so some flexibility is again advised. As a consequence 500m was not a prescribed policy of the Welsh Government. In February 2021 Future Wales was published and replaced TAN 8. Future Wales does not make reference to a buffer between residential dwellings and wind turbines. Policy 18 sets out detailed criteria which need to be met if Developments of National Significance (which include large scale wind farms) are to be permitted. Criteria 7 includes the examination of noise, flicker, reflected light, air quality and electromagnetic disturbance. It is for Planning Environment Decisions Wales (PEDW) to assess applications for DNS proposals.
Reference to 500m is still made in the practice guide ‘Planning for Renewable and Low Carbon Energy - A Toolkit for Planners’ (2015), however this is not policy. The Toolkit refers to rules of thumb used by industry for the early assessment of sites to determine the size of separation buffers to avoid noise becoming an issue.
Practice Guidance – Planning Implications of Renewable and Low Carbon Energy (2011) sections 3.4.7 - 3.4.8 indicates that careful consideration of the siting and layout design of individual turbines/wind farm is important to ensure that increases in ambient noise levels around noise-sensitive development (i.e. residential properties) are kept to acceptable levels in relation to existing background noise. Increases in noise levels can be minimised by ensuring that there is sufficient distance between the turbines and residential properties. Predicted operational noise levels should fall within the established limits of ETSU-R-97 (The Assessment and Rating of Noise from Windfarms (1997) Energy Technology Support Unit). This guidance sets out indicative noise levels thought to offer a reasonable degree of protection to wind farm neighbours, without placing unreasonable restrictions on wind farms.
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Excerpt from Facilitating Planning for Renewable Energy in Wales: Meeting the Target - Final Report about windfarm buffers.
Table 5.1 Absolute constraints to large-scale wind energy development in Wales (p.54)
(i.e. settlements of village size
|Whilst there is an emerging best practice approach
within the onshore wind industry of siting development
more than 500m from residential properties (for
noise/amenity and safety reasons) there are no other
reasons why wind energy developments cannot be
located within urban areas e.g. on former industrial
land. The Welsh Assembly Government have recently
commissioned research which specifically attempts to
identify available urban and brown field sites for wind
turbines / wind farms. The study identifies some 144
MW of potential installed capacity in small to medium
sized wind farms. (i.e. ≤ 25MW). The brief for this
study however was to identify strategic areas for large
(i.e. ≥ 25 MW) wind farms and it was felt that such
developments were incompatible within urban areas.