Scottish Planning Policy is a material consideration which helps planning authorities shape development plans and make decisions on wind farm developments. The potential visual impact of wind farms is an important factor in plan-making and in these decisions. In order to minimise the visual impact of wind farms, the current Scottish Planning Policy (2010) recommends that planning authorities apply a 2km separation distance between potential sites for onshore wind farms above 20MW and the edge of cities, towns and villages. The 2km separation has in general been well received by planning authorities, communities and developers but there is a lack of clarity about the evidence base for setting this specific distance.
ClimateXChange was asked by the Scottish Government to examine the evidence base for the separation distance. The project reviewed a wide range of relevant sources from over 15 countries. It found that most separation distances have been set based on noise, shadow flicker or health considerations, with none specifically relating to visual impacts. The study found no direct link between the evidence and the policy for a 2km separation distance.
The size of onshore wind turbines has been increasing and is expected to increase in coming years. This study therefore also looked at whether there is evidence to support an increase in the 2km distance to reflect this trend. It found that, even in the few cases where visual impact had been a key consideration for setting separation distances, no reference had been made to turbine heights.
After reviewing UK and international literature on the use of separation distances for onshore wind farms, the study discusses ways that planning policy might be revised, for example:
- by articulating a clear understanding of the impact of the current 2km distance (positive and/or negative);
- by finding ways to improve engagement with stakeholders, and ways to better understand the subjective aspects of how people perceive the visual impact of wind turbines;
- by expanding the descriptions of the criteria that planning authorities should consider in identifying different zones (Para 190 in the current SPP).