The DTBird system, designed to reduce bird collisions at wind farms, was evaluated by the Renewable Energy Wildlife Institute (REWI) at two wind farms: Manzana in California and Goodnoe Hills in Washington, USA. Funded by the U.S. Department of Energy, the study focused on the system's effectiveness in detecting and deterring large raptors, particularly Golden and Bald Eagles.
At the Manzana site, the DTBird V4D4 model was installed on seven turbines, each with a tower height of 65 metres and a rotor diameter of 82.5 metres. The study at this site lasted for nine months.
At the Goodnoe Hills site, the DTBird V4D8 model was installed on 14 turbines, each with a tower height of 87 metres and a rotor diameter of 110 metres. The study at this site lasted for two years.
Key Findings
1. The DTBird models reduced the likelihood of eagles and large raptors entering the rotor-swept zone by 20-30%. Additionally, there was a deterrence rate of over 40% for eagles flying directly toward the zone.
2. The overall probability of detecting large raptors was 65% within 240 metres. This detection rate was highest at 75% within the 50-75 metre range and decreased to 30% at a distance of 380 metres.
3. The effectiveness of the deterrence responses was 73% at the Manzana site and 63% at the Goodnoe Hills site. Golden Eagles showed a higher responsiveness at Manzana (79%) compared to Goodnoe Hills (60%).
4. The deterrence measures reduced the dwell time of eagles near the turbines by 24-27%. Birds, especially eagles and vultures, responded better to the deterrence signals as wind speed increased.
The report suggests improving camera resolution and AI algorithms to enhance detection accuracy and reduce false positives. Regular maintenance of camera lenses is also recommended to prevent solar degradation from affecting detection capabilities.
