KHO:2023:73 – Yearbook decision from the Supreme Administrative Court reverses current practice of applying building permits for wind turbine generators in building permit applications

The Supreme Administrative Court rules in a recent yearbook decision KHO:2023:73 that the building permit application regarding a wind turbine generator must contain exact key dimensions of the structure (i.e. tip height and hub height/rotor diameter). Presenting only the maximum tip height and providing the final dimensions before start of construction will not be sufficient.


As a result of the constant technological development of wind turbine generators (“WTGs”), it is often challenging for project developers to present the exact dimensions and technical specifications the WTGs at the time when building permits are applied. It is not uncommon that the WTG model based on which the building permit applications have been prepared is no longer available on the market at the time when all necessary permits and approvals needed for start of construction have gained legal force and the WTGs are ordered, meaning that constructing the WTGs will either require a deviation from the original drawings presented in the building permit application or a revision of the permit altogether.

As an attempt to tackle this challenge, some permit applicants have adopted a practice of presenting certain maximum dimensions, often only the maximum tip height of the WTG, in the building permit applications, and delivered the exact dimensions and technical specifications of the WTGs before the start of construction works, when the final WTG model has been selected and ordered. Such practice was based on an interpretation of Section 134 Subsection 2 of the Finnish Land Use and Building Act (Fi: maankäyttö- ja rakennuslaki, 132/1999), which allows, in the lack of exact drawings, the permit authority to assess the general conditions for granting a building permit based on other available data, provided that the exact drawings are presented, and subsequently approved, by the authority prior to start of construction.


However, on 25 August 2023, the Supreme Administrative Court (“the Court”) ruled in a yearbook decision (KHO:2023:73) that the practice described above is unlawful and revoked the building permits. According to the Court, since neither the building permit decision nor the drawings attached to it indicate the key dimensions of the WTGs (i.e. tip height an rotor diameter), it is not possible to establish what construction measures the permit applicant is entitled to or what the actual effects on the neighborhood are. The Court further stated that it could not be ensured that the data presented in the noise and flicker modeling’s attached to the building permit application correspond to the maximum effects of the WTGs on the neighborhood when the key dimensions were left open.

The Court argued that whereas the Land Use and Building Act does not require that the technical identification information of the project, such as a specific WTG model of a wind turbine manufacturer, should be presented when deciding on building permits for WTGs, the identification information of the WTG presented in building permit applications and master drawings must nevertheless be sufficiently precise so that it is possible to reliably assess whether the conditions for granting a building permit exist. Correspondingly, the permit regulations to be included in building permit decisions must be sufficiently precise to ensure the conditions for granting the permit. In this case, presenting the mere maximum tip height of the WTGs was not considered sufficient, since it could not be established that the noise and flicker modellings conducted for a specific WTG type, which the applicant had presented in connection with the building permit applications, would categorically depicture the maximum impacts for all theoretical alternative rotor dimensions allowed under the 240-metre maximum tip height. The Court gave no relevance to the fact that the permit applicant had included a statement in the building permit application declaring that the modeling’s were conducted to estimate the maximum effects caused by the project and that the applicant would present new modellings if the WTG to be built were to differ from the type used in the impact assessment.


This decision from the Court is a good reminder of how cautious one must be in interpreting the re-quirements set out in general construction laws in connection with renewable energy projects. Structures such as 240-metre high WTGs or e.g. solar panel fields covering hundreds of hectares of land are simply very different from, and involve different legal issues than, the traditional construction projects for which such laws were originally designed. The decision sets out tougher requirements for wind power developers, as it will no longer be sufficient to only determine the maximum tip height for the WTGs in the building permit applications. As a result of this decision, the permit applicant will have to determine exact dimensions of at least two main factors (tip height + either hub height or rotor diameter) of the WTG, even though there is no certainty of whether there will be a WTG-model with those specific dimensions available on the market at the time when the WTGs are ordered.

We further note that the decision does not take a position on whether it is still possible to present several different turbine model alternatives (and noise and flicker modelling reports for each and every turbine model) in the building permit application, and then, at a later stage specify which model is chosen from the options in the building permit conditions.

Share content

Read also