Several bird species have demonstrated a strong tendency to avoid flying through an offshore wind farm in Dutch waters, while others pass through the area but successfully avoid turbine rotors.
This is a central conclusion of a six-year research project focusing on the 108MW Egmond aan Zee offshore wind farm, commissioned by Nuon and Shell and led by Dutch consultancy, Bureau Waardenburg.
A substantially-lower number of birds fly through the wind farm than would be expected. However, a small number of species, including cormorants and several gull species, do not practice "avoidance" in the vicinity of Egmond aan Zee, the research found.
This is not the first piece of research recording avoidance practices by bird species. Migrating pink-footed geese have been recorded avoiding Lynn & Inner Dowsing offshore wind farm.
Species with the greatest risk of collision with turbines at Egmond aan Zee appear to be migrating passerines, such as thrushes. These species are at higher risk primarily due to the sheer number of individual birds that pass through the area during migration. Most of the migrating birds avoid the wind farm’s turbines by flying above rotors, but some fly at a lower height, the researchers found.
Collision risks for many bird species are probably higher onshore than offshore, the authors point out, with structures such as overhead transmission lines, buildings and trees posing a greater threat than the Egmond aan Zee turbines.
It is likely that higher avoidance rates by some bird species will be recorded in future, once improvements are made in bird detection radar technology, the researchers also note.
Since completing the Egmond aan Zee research, Bureau Waardenburg has advised a number of offshore wind developers including Eneco and Mainstream Renewable Power, with work for the latter focusing on both the 4GW Hornsea zone and the 450MW Neart na Gaoithe project.
The consultancy hopes to contribute to upcoming strategic environmental assessments (SEAs) that will be completed for the Netherlands’ third round of offshore wind development, Windpower Offshore understands.