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If masses of birds are expected to be migrating across the North Sea, the Minister of Climate Policy and Green Growth issues the recommendation or decision to stop the offshore wind turbines. This page gives details of relevant information.

Notifications 2024

Notification, 16 March 2024

Notification of recommendation to limit rotation speed of offshore wind turbines in connection with mass bird migration

The Minister for Climate Policy and Energy recommends that the number of revolutions per wind turbine in the specified wind farms in the plot decisions referred to below be reduced to fewer than 2 per minute on 16 March 2024, from 9.00 p.m. to midnight (Central European Time).

This recommendation applies to the offshore wind farms in the following plot decisions:

- Plot decision I, Borssele wind farm zone, as adopted on 24 March 2016 and amended on 24 January 2021;
- Plot decision II Borssele wind farm zone, as adopted on 24 March 2016 and amended on 24 January 2021
- Plot decision III Borssele wind farm zone, as adopted on 24 March 2016 and amended on 24 January 2021;
- Plot decision IV Borssele wind farm zone, as adopted on 24 March 2016 and amended on 24 January 2021 and amended on 24 January 2021;
- Plot decision V (innovation) Borssele wind farm zone, as adopted on 24 March 2016 and amended on 24 January 2021;
- Plot decision I Hollandse Kust (zuid) wind farm zone, as adopted on 8 December 2016 and amended on 24 January 2021;
- Plot decision II Hollandse Kust (zuid) wind farm zone, as adopted on 24 March 2016 and amended on 24 January 2021.

Wind farm operators Ørsted (Borssele 1 & 2) and Vattenfall (Hollandse Kust (zuid) 1 - 4 inclusive) have indicated that they will follow the recommendation to reduce the rotation speed of the wind turbines. Wind farm operators Blauwwind (Borssele 3 & 4) and Two Towers (Borssele 5) have indicated that they will not follow the recommendation.

Legal framework

During periods in which birds migrate across the North Sea, there is a chance that their course will put them at risk from the wind turbine rotors. To limit the number of birds that fall victim to wind turbines, the Minister of Climate Policy and Green Growth (prior to 2 July 2024 the Minister of Climate Policy and Energy) has opted to incorporate a provision in the plot decisions for offshore wind farms. This provision implies that at night time (between sunset and sunrise), at times when masses of birds are migrating, the number of rotations per minute, per wind turbine, must be reduced to fewer than 2. The authority to issue a decision to stop the wind turbines is vested in the Minister under the terms of article 3 of the Offshore Wind Energy Act (Wet windenergie op zee) (opens in new window) (links to a different website).

Legislation specifies what is meant by 'mass bird migration', namely at least 500 birds per kilometre, per hour. From that quantity of birds upwards, the Minister may issue a decision to stop the offshore wind turbines. In addition, the Minister issues recommendations to stop the offshore wind turbines. The Minister may recommend stopping the turbines from 151 birds per km/hour. In contrast to a formal decision, a recommendation puts no obligation on permit holders; a recommendation puts the issue of whether or not to reduce revolutions per minute with the wind farm owners.

What is the mechanism for reaching a recommendation?

The starting point is a prediction relating to bird migration across the North Sea, generated by a bird-migration prediction model developed by the University of Amsterdam on behalf of the government. If, in a specific time period, that model makes a prediction for bird migration on a specific night that exceeds a specific number of birds per kilometre, per hour, it is considered to be a mass bird migration. A special team of bird-migration experts reviews the prediction. At the same time, grid operator TenneT analyses the risks associated with the security of generating electricity. Ultimately, the Minister of Climate Policy and Green Growth decides whether or not to issue a recommendation to reduce the rotation speed of the offshore wind turbines to fewer than 2 revolutions per minute.

It is not possible to object to a recommendation, nor to lodge an appeal against it. Operators of offshore wind farms to whom this recommendation applies are notified of the recommendation.

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