Many countries apply what is known as the “2 Km rule” – that is turbines must be at least 2 Km from any private residences. The reason, in part is to do with “flicker”.
Shadow-flicker from wind turbines is defined as alternating changes in light intensity caused by rotating blades casting shadows on the ground and stationary objects such as a window at a dwelling.
Shadow-flicker can occur in project area homes when the turbine is located near a home and is in a position where the blades interfere with very low-angle sunlight (eg. at sun-set). The most typical effect is the visibility of an intermittent light reduction in the rooms of the home facing the wind turbines and subject to the shadow-flicker. In addition to this – the moving blades of a turbine will cast moving shadows outside of the house creating a highly objectionable nuisance.
Flicker can be seen over a wider distance where wind farm sites are on higher ground relative to the homes near the site – as is the case with Pickworth. SSE proposed site is around 100m above sea level, Pickworth is around 70 m above sea level.
Using simple geometry, turbine blade shadows will be cast over Pickworth once the sun is setting below 6 degrees. This will occur earlier and last longer the closer the location is to the site.
If you take the dogs for a walk or go horse riding this alternating shadow – flicker – will be a significant irritation.