Do demand-based obstruction lights on wind turbines increase community annoyance? Evidence from a Danish case

Adverse impacts from wind turbine obstruction lights have received little attention in literature and practice with respect to community annoyance with wind energy and studies on the effects of mitigation measures are absent. Technology development has made demand-based obstruction lights possible, allowing lights to be turned on only when aircrafts are approaching. The aim of this study is to investigate the effects of demand-based obstruction lights on community annoyance while considering the intervening effects from other influential factors. This is done by means of a before-after study of the installment of a demand-based obstruction light technology at a test center for wind turbines with a height up to 330 m in the northern part of Denmark. The results document that a radar-based obstruction light controlling system contributes to the reduction of community annoyance, but that annoyance is also influenced by several factors besides the direct impacts from obstruction lights. The results underscore the importance of communicating the effects of the radar system during the planning phase and when implemented. The findings thus provide important evidence that informs the efforts made by developers and authorities to reduce annoyance and increase community acceptance of wind turbines as part of the green transition of societies.