Between the end of 2021 and 2025, the province of Groningen, RWE and TNO  investigated whether painting of one turbine blade of a wind turbine black helps birds fly safely between wind turbines.

Previous research in Norway, on the island of Smøla, showed that painting one blade of a wind turbine black results in 70% fewer bird deaths among certain species of birds. It was investigated whether this also applies to the situation in the Netherlands, with different bird species and a different landscape. In this study, the number of birds that may have flown into a turbine was counted by hand. This provided limited insight into when and how this happened. Nor did it provide any insight into any differences in bird behavior around a turbine with a black blade and a turbine without such a black blade.

Results

In early 2025, the study at Eemshaven was completed. The study found that painting one rotor blade black did not significantly reduce bird strikes. This may be because one black blade does not contrast enough with the busy background. However, this does not mean that making rotor blades more visible cannot be an effective measure, as positive results have been obtained at other sites such as Smøla and in South Africa with a black blade and red banding, respectively. To draw real conclusions, follow-up research is needed on the underlying mechanism, such as whether birds see the turbines at all and whether different flight behavior of birds affects them. Alternative patterns and colours that increase contrast with the surroundings should also be tested. Furthermore, it is important to combine ongoing studies to properly evaluate effects in different situations and locations.