The province of Groningen in the Netherlands and energy company RWE are investigating whether painting a wind turbine blade black will help reduce the number of bird victims. This is to be carried out in collaboration with other authorities and private parties, including Vattenfall.

The plan is to paint black seven of RWE’s existing turbines in Eemshaven. Each WTG has a blade tip height of 140 metres. The study has already started and is expected to run until the end of 2024.

The decision follows a study financed by Vattenfall and a group of Norwegian partners on the island of Smøla in Norway. The study showed that painting one blade of a wind turbine rotor black resulted in 70 % fewer collision bird victims. "That has to do with the way birds perceive the moving rotor of a wind turbine," says Jesper Kyed Larsen, an environmental expert at Vattenfall. "When a bird comes close to the rotating blades, the three individual blades can 'merge' into a [single indistinct image] and birds may no longer perceive it as an object to avoid. One black blade interrupts the pattern, making the blending of the blades into a single image less likely."

The Eemshaven study will determine what effects can be expected in the very different landscape of The Netherlands, country that is home to different bird species and with different meteorological conditions. Jesper Kyed Larsen again: "We are continuously looking at ways to reduce the impact of wind turbines on the environment, and we are therefore very excited to be part of this study at Eemshaven to better understand the potentials of the black blade measure in a Dutch context. If we could find other ways of reducing collision risk to birds than temporarily stopping the turbines, and losing renewable energy production, that would of course be better for everybody.”

The study will also attempt to discover whether human perceptions of the black coloured blades will be affected adversely or otherwise in the very different weather conditions of The Netherlands, where sunshine and blue skies are more often experienced than off the west coast of Norway.

This year a baseline measurement will be carried out. For 2023, the blades will be painted black, and the number of collision victims will be monitored for two years. In addition, aviation safety and the impact of the black blade on the landscape and the painted blades themselves will be examined.