1. Shadow flicker may occur under certain conditions when the sun passes behind the rotors of a wind turbine and casts a shadow over neighbouring properties. As the blades rotate, the shadow flicks on and off, an effect known as “shadow flicker”.
2. The effect is likely to be most pronounced inside buildings, where the flicker appears through a window opening. The likelihood and duration of the effect depends upon:
• Direction of the property relative to the turbine(s): in the UK, only properties within 130 degrees either side of north, relative to the turbines, can be affected, as turbines do not cast long shadows on their southern side;
• Distance from turbine(s): the further the observer is from the turbine, the less pronounced the effect would be. Flicker effects have apparently been proven to occur only within ten rotor diameters of a turbine;
• Turbine height and rotor diameter;
• Time of year and day; and
• Weather conditions (i.e. cloudy days reduce the likelihood of effects occurring).
Why will we be affected?
3. On the basis of the evidence so far provided by Volkswind about the proposed size and location of the turbines, it seems likely that a significant number of Ringstead residents could be affected. This is because:
• The whole village lies within 130 degrees of the eastern side of North where flicker effect may occur.
• The turbines proposed at Ringstead Grange will have rotor diameters of 90 – 93 metres. This means that shadow flicker may extend to at least 930 metres from the turbine nearest to the village. Given that the turbines will be located on an elevated position above the village, the impact may extend further – perhaps beyond one kilometre. This would bring most, if not all, of the village within the range of potential flicker effect.
• Properties with windows facing towards the turbines are most likely to be affected.
When will we be affected?
4. Given the position of Ringstead in relation to the turbines, shadow flicker is most likely to be experienced in the afternoon and evening when the sun is to the south-west of the turbines. The duration of any flicker effect will, of course, vary from day to day depending on the weather conditions.
What does shadow flicker actually feel like?
5. You can see examples of what it actually feels like to experience shadow flicker on your property, by using these links to YouTube videos:
