Offshore wind farms shut down for first time to protect migratory birds
On Saturday 13 May 2023, the offshore wind turbines of Borssele III and IV wind farm of the Blauwwind consortium (of which Eneco is a partner) were shut down for four hours, as massive bird migration over the North Sea had been predicted. The purpose was to give the birds safe passage. Borssele I and II and a wind farm near Egmond aan Zee were also shut down. The measure has been applied for the first time and is in line with the approach of the government and participating companies to make ecology and biodiversity increasingly central to offshore wind farms. Wind farms are expected to be shut down more frequently from autumn 2023 to allow migratory birds good passage through wind farms in the North Sea.
Minister for Climate and Energy Policy Rob Jetten: "This is an international first, nowhere else in the world are offshore wind farms shut down to protect birds during mass bird migration. We want to minimise the impact of wind farms on nature and this measure is one of the ways we do this. All parties involved worked well together and set this up in a relatively short time, so it is a great initiative that I am very proud of."
To give birds safe passage, wind farm owners now reduce the speed of wind turbines to a maximum of two rotations per minute during predicted night-time peak migration.
In late 2022, a PhD student at the University of Amsterdam (UvA) produced a bird migration prediction model that predicts bird migration two days in advance. The model uses weather data and several bird radars in the North Sea. A group of migratory bird experts also predicts the likelihood of major bird migration two days in advance. The two-day timeframe gives grid operator TenneT time to ensure the stability of the high-voltage grid. That time will also be used to inform all parties concerned and carefully initiate the shutdown of the turbines.
Tim van Oijen of Vogelbescherming Nederland (the Netherlands Bird Protection Society): "Twice a year, in spring and autumn, millions of birds migrate across the North Sea on certain nights. With the growth of wind farms in the North Sea, it is extremely important that we do this in the most ecologically responsible way possible, with minimal impact on the North Sea. Temporarily shutting down the turbines during bird migration contributes to this."
This first implementation of the measure is part of the pilot phase this spring to see if all systems do what they are supposed to do: from forecasting to shutting down wind turbines. The measure will officially take effect in autumn 2023 and will continue to be improved from then on. Wind farms currently under construction, as well as future wind farms, will also participate in the measure. The wind sector, the University of Amsterdam and the government are continuously conducting research on bird migration in the North Sea so that the effectiveness of the measure can be steadily improved.
Rijkswaterstaat developed the procedure on behalf of the Ministry of Economic Affairs and Climate with wind farm owners, grid operator TenneT, the Ministry of Agriculture, Nature and Food Quality, Vogelbescherming Nederland and the North Sea Foundation, among others.