Bird collisions with wind turbines are one of the biggest challenges associated with the development of the renewable energy industry in terms of the environmental impact of investments. During the implementation of numerous projects and EIA procedures, we consistently seek innovative ways to reduce the negative impact of wind farms on nature, which is why we actively participate in numerous national and international conferences. One of such events was the 8th Conference on Wind Energy and Wildlife Impacts (CWW) in France (https://ambiens.pl/blog/ambiens-team-at-8th-conference-on-wind-energy-and-wildlife-impacts-in-montpellier/ ), where we updated and expanded our existing knowledge of a mitigation method that involves painting selected elements of wind turbines – most often the blades – with contrasting colours.
The aim of this measure is to increase the visibility of rotating blades for birds, which often fail to notice them during flight due to the so-called motion smear effect, which causes fast-moving blades to form an almost uniform, difficult-to-see surface in the animal’s field of view. Although this idea has been appearing in publications for a long time, it gained attention only in 2020 thanks to research by Norwegian scientists from the island of Smøla, who noted a significant decrease in the number of collisions after repainting the turbines. Compared to unpainted wind turbines, the reduction in collisions was as high as 70% (May R., Nygård T., Falkdalen U., Åström J., Hamre Ø., Stokke B., 2020, Paint it black: Efficacy of increased wind turbine rotor blade visibility to reduce avian fatalities, Ecology and Evolution, 10(16): 8927-8935).
Wind turbine at the Smøla wind farm (Norway) with a blade painted black (May et al. 2020)
Following the publication of the results from Norway, similar tests were carried out in Denmark, South Africa and the United States, to mention a few, but the results were not always clear-cut. In some cases, there was a distinct decrease in the number of collisions, while in others the differences were within the margin of statistical error. This indicates that the effectiveness of this method may be strongly dependent on local conditions – the species present in the farm area, the configuration of the wind turbines, the landscape, or the season – as well as on the patterns and colours used.
Black patterns are currently considered to be the most effective. It should be emphasized, however, that they are not always compliant with relevant regulations, so red is an acceptable alternative. In addition, although different patterns may have different effects on individual species, stripes remain the most universal.
Different ways of painting wind turbines
Although the concept of painting turbine blades seems simple and potentially effective, its implementation in practice faces a number of technical and logistical limitations. Painting existing wind turbines is difficult to implement due to the height of the structures and the necessity to shut it down. It requires the use of specialized equipment and often favourable weather conditions. Therefore, this solution is much easier to apply at the production or assembly stages of new turbines than in the case of existing ones. In practice, aesthetic and social issues must also be considered. The colour-changed blades may affect the visual perception of the landscape, which is important in assessing the impact of the investment on the landscape and in the permit application process. Most importantly, existing data is still insufficient to consider this method a standard and effective mitigation measure.
Installation of a wind turbine
In summary, painting wind turbines can be a valuable tool for bird protection, but its effectiveness and applicability must be assessed on a case-by-case basis in the context of local environmental and technical conditions. Further long-term research is needed to clearly determine the conditions under which this method brings real benefits to avifauna. We are constantly monitoring progress in this area, combining concern for the country’s natural environment with the suitability of implementing innovative methods of its protection.