The French company Biodiv-Wind¹ publishes the first study explaining how Avian Detection Systems (ADS) reduce the risk of bird collisions with wind turbines.
Stopping the rotation of a wind turbine when a bird is in close proximity during flight to prevent a collision? The solution seems obvious. However, until now, no study has scientifically explained it.
To achieve this, the Biodiv-Wind team analyzed data from their SafeWind systems, which detect birds in real-time and can automatically trigger the shutdown of wind turbines and restart them when the birds have moved away.
Nearly 600,000 videos of the detection of the Red Kite (Milvus milvus), a protected and particularly vulnerable species, were collected over four years from 251 European wind turbines. These videos were then cross-referenced with data on blade rotation speed.
The detailed results are presented in the attached FactSheet. It is revealed that the Red Kite has more difficulty anticipating danger when the blade speed exceeds its flight speed range, which can reach up to 76 km/h. Specifically, slowing down a wind turbine to a speed of 110 km/h at the blade tips would reduce the collision risk by more than 90%.
This result is significant. In fact, this speed threshold is close to the minimum production speed of certain modern wind turbines. Instead of completely stopping a wind turbine, it would be possible to simply slow it down to drastically reduce the collision risk. This would maintain a minimum level of production, reducing economic losses, and, most importantly, avoiding interruptions in connection to the electrical grid, which complicates its management and reduce the lifespan of installations.
However, risk reduction does not mean complete elimination, as collisions have been observed on wind turbines in functional shutdown. Further research is needed to better understand these situations and provide a solution.
Nevertheless, these results, combined with other recent scientific studies demonstrating that the risk of collision is nearly zero for certain raptors beyond 200 meters from wind turbines (Rolek, 2022)², provide robust new avenues for reconciling biodiversity preservation and wind power generation.
- Biodiv-Wind SAS is a French company based in Occitanie. It has a team of 47 employees, including ecologists, software developers, and technicians. Since 2015, the company has installed its SafeWind systems on nearly 480 wind turbines in 9 countries.
- Rolek and al. : Flight characteristics forecast entry by eagles into rotor-swept zones of wind turbines, Ibis (2022), 164, 968-980.
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