Energy transition: offshore wind farms stopped to protect migratory birds
A new model predicts two days in advance at what height the birds will fly over the sea
Source: picture alliance / ZB
Millions of birds migrate across the North Sea twice a year. There are dangers from wind farms. Now the Netherlands have switched off wind turbines for the first time after a bird migration warning. The forecast is based on a new model.
“The Netherlands has switched off wind turbines at sea for the first time to protect millions of migratory birds. Two offshore wind turbines were shut down for four hours on Saturday because massive bird migration was predicted over the North Sea, the government said. “This is an international first,” said Secretary of Energy Rob Jetten. Nowhere else in the world would offshore wind farms be shut down to protect birds. The government wants to keep the impact of wind farms on nature as small as possible.
It is about a pilot project in Borssele in the southwest of the country and in Egmond aan Zee in North Holland. It is made possible by a model that can predict bird migration two days in advance. It was developed by a doctoral student at the University of Amsterdam in late 2022. It is expected to be introduced in all wind farms from autumn 2023 and these will then also be switched off more frequently.
The model predicts two days in advance at what level the birds will be dragged across the sea. This is done on the basis of data from bird radars and current weather forecasts. Experts on migratory birds also make predictions about bird migration.
According to the ministry, power grid operator Tennet has enough time to ensure the stability of the high-voltage grid and to initiate the shutdown of the turbines. During the predicted flyover, the speed of the turbines will be reduced to a maximum of two revolutions per minute.
Tim van Oijen from the national bird protection organization spoke of an important project in view of the increasing number of wind turbines at sea: “Twice a year, in spring and autumn, millions of birds migrate across the North Sea on some nights.” It is extremely important that the expansion of the wind farms will have minimal impact on the local ecosystem.
There are currently seven wind farms with an output of around 2.5 gigawatts off the Dutch North Sea coast. By 2030, far more wind farms are to be erected with a total output of around 21 gigawatts.
In Germany, too, the planned strong expansion of wind energy on the North Sea and Baltic Sea represents a danger for migratory birds according to biologists. There are currently 22 wind farms in the North Sea and 3 in the Baltic Sea off the German coast, with a total capacity of 8, 1 gigawatt. By 2030 it should be 30 gigawatts, by 2045 the total output should increase to at least 70 gigawatts according to the offshore wind energy law that came into force at the beginning of the year.
Ministries, the network operator Tennet, owners of the wind farms and environmental and bird protection organizations worked together on the Dutch project. The project will continue to be scientifically supported after its official launch in autumn.
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