Review of Light and Shadow Effects from Wind Turbines in Scotland

How light and shadow effects from wind farms are considered in the development planning process in Scotland was raised in our report Wind Farm Impacts Study, published in July 2015. The Impact Study made a number of recommendations for developing better guidance on predicting and limiting the impac of wind farm developments.

The findings in this follow-up study aims to feed in to the Scottish Government thinking on how light and shadow effects are assessed and considered through the planning process, and potentially inform future guidance for developers and planning authorities.

The research makes a number of recommendations:

  • There needs to be consistency between guidance documents and planning policy on the definition of shadow flicker
  • A definition of the outdoor effects of light and shadow related effects should be included for clarity
  • Guidance should 
    • include acknowledgement of the issue of reflected light
    • clarify the likely requirement for visible lighting, and how potential landscape and visual effects should be addressed
    • explicitly set out the parameters when shadow flicker may occur and which are required for likely case scenario modelling
    •  not include reference to the occurrence of shadow throw ‘within 130 degrees either side of north’.
    • exclude reference to the 10 rotor diameter distance
    • set out the need to consider cumulative shadow flicker and further guidance on how this should be approached
  • There is also a need for guidance on the thresholds of exposure to shadow flicker in Scotland; and on different factors which may affect the sensitivity of different types of receptor to light and shadow related effects.