London, UK — A Parsons Brinckerhoff study on turbine shadow flicker has concluded that the frequency of the flickering poses no significant risk to health, while the few problems that have arisen have been resolved effectively using mitigation measures, in particular turbine shutdown systems.
Commissioned by the UK’s Department of Energy and Climate Change (DECC), the peer reviewed study concludes that developers employ no standard methodology when introducing environmental and site specific data into shadow flicker assessments. The three key computer models used by the industry — WindPro, WindFarm and Windfarmer — use a ‘worst case scenario’ approach and overlook factors such as wind speed and cloud cover that can reduce the duration of the shadow flicker impact.
On health effects and the nuisance of the shadow flicker effect, it found the frequency of the flickering from wind turbine rotation should pose no significant risk to health. Shadow flicker is more likely to affect residential amenity than health. Only dwellings within 130 degrees either side of north relative to a turbine can be affected and the shadow can be experienced only within 10 rotor diameters of the wind farm.
Having considered the report’s findings, the UK government has concluded that existing planning guidance on shadow flicker is fit for purpose, and no changes to it are necessary.