The Supreme Administrative Court ruled on the coordination of adjacent wind farms

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The Supreme Administrative Court issued on 12 August 2026 a precedent concerning the assessments required for a partial master plan enabling a wind power project, in a situation where an already-built and operational wind farm was located next to the plan area.

In this case, the city had approved a partial master plan for six new wind turbines adjacent to an existing wind farm. Under the partial master plan, the new turbines were positioned upwind of the neighbouring farm’s turbines relative to the area’s prevailing wind direction, at a short distance.

The owner of the operating wind farm primarily sought annulment of the entire decision on three grounds: (i) the new turbines would impair the operating wind farm’s electricity generation due to wake effects, i.e. reduced wind speed and increased turbulence; (ii) the increased turbulence would cause wear to the structures of the operating farm’s turbines and shorten their service life, resulting in costs; and (iii) the risk of ice falling from the new wind turbines would compromise the occupational safety of personnel working in the neighbouring wind farm area.

It is noteworthy that, during the zoning process for the new wind farm, the plan’s impacts on the operations of the adjacent wind farm were not assessed. In the appeal, the owner of the adjacent wind farm submitted a report stating that the construction of the new project would have caused the neighbouring wind farm to suffer an annual loss of production of up to 2.8 percent.

The Administrative Court, as the first instance, dismissed the appeal in its entirety. The Supreme Administrative Court granted a leave to appeal and ruled on the question of whether the partial master plan approved by the city’s decision had been based on sufficient studies and impact assessments.

The Supreme Administrative Court rejected part of the claims – the impact on electricity production was decisive

The Supreme Administrative Court rejected the appellant’s claims concerning the risk of falling ice and wear to the structures. On these points, it agreed with the Administrative Court’s view that the risk of falling ice did not cause unreasonable harm to the appellant. The Supreme Administrative Court assessed the wear to the structures as an effect that would manifest over the long term and be difficult to predict, and found that the failure to assess it was not, in this case, grounds for annulling the plan.

Instead, the Supreme Administrative Court held that the impact on electricity production is a direct effect: it follows directly from the fact that, under the plan subject to appeal, new turbines could be built upwind of the operating farm relative to the prevailing wind direction. Taking into account the distance between the turbines, the area’s prevailing wind direction and the size of the turbines, the Court held that it could not be ruled out that the new wind farm would significantly impair the neighbouring farm’s production through wake effects. The plan could, therefore, cause unreasonable harm to the neighbouring wind farm. Because this effect had not been assessed at all when the new plan was drawn up, the Supreme Administrative Court annulled the decision approving the plan.

What does the precedent mean for the zoning of wind power projects?

Based on the Supreme Administrative Court’s ruling, when preparing a partial master plan, existing wind farms located in the vicinity of the planned wind farm and the impacts on their production must also be taken into account as part of the impact assessments for a new wind farm’s master plan. The issue has not previously been resolved in legal practice, and project developers should take these principles established by the decision into account in their wind power master plan processes.

In addition, the decision confirmed that users of areas outside the master plan area must also be taken into account when assessing the reasonableness of the effects caused by a plan. The Supreme Administrative Court further ordered the city to reimburse the legal costs of the company owning the neighbouring wind farm.

However, the decision did not address whether the production impacts on the already operating wind farm would have been considered unreasonable had they been assessed as part of the new project’s zoning process.

 

Our experts are pleased to discuss this decision further, as well as other questions relating to the zoning of wind power projects.

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