Wind Turbines and Pylons: Guidance on Separation Distances

Commissioned in response to a growing number of applications for single or small clusters of wind turbines—too small to be classified as wind farms but still capable of impacting residential views—the study addressed the gap in national guidance on setting separation distances based on visual impact. While GLVIA3 provides a framework for assessing visual effects, there is no standardised method for determining minimum distances. Current Welsh Government advice is that each case should be judged independently and on its own merits.

To bridge this gap, Gillespies developed a clear, user-friendly visual assessment tool to support developers and planning officers in evaluating the potential visual impact of turbines and pylons on residential communities.

The study introduced the concept of residential visual amenity ‘trigger distances’ based on a mathematical formula for assessing the apparent height of a turbine or pylon.

Although there are common threshold criteria which have been applied by Planning Inspectors when considering the acceptability of impacts on residential visual amenity, to the best of our knowledge, this is the first time that an empirically derived approach has been developed and tested for application to specific development types.

The work won a national Landscape Institute Award in 2015 in recognition of its innovation in providing a new consistent approach to assessing the acceptability of vertical infrastructure on residential visual amenity. In so doing it has progressed the understanding of visual impact assessment. 

The study is one of the supporting documents for the Anglesey and Gwynedd Joint Local Development Plan and is being used in the consideration of local planning applications. It can be adapted