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In Brief
02. Jun 2025

Renewable energy sources - Solar units on historic listed buildings are permissible

Historisches Hausdach mit Solaranlage

Owners of historic listed buildings are generally able to obtain permits for the installation of solar units in accordance with building preservation regulations. The Supreme Administrative Court (Oberverwaltungsgericht, OVG) in Münster, in two landmark cases, clarified that the public interest in the expansion of renewable energy sources normally takes precedence over the matters related to building preservation.

Recently, the OVG had to rule on two similar cases. In the first case, the owner of a single-family home in an historic listed residential settlement in Düsseldorf wanted to install solar modules on a partially visible rooftop area. The city of Düsseldorf refused to provide the necessary permit under building preservation regulations for this. The Administrative Court in Düsseldorf allowed the claim and required the city to give permission. In a second case, the city of Siegen declined to give a permit under building preservation regulations for a solar unit on the roof of a former school that had been entered into the list of historic monuments. This decision was initially upheld by the Administrative Court in Arnsberg.

However, on 27.11.2024 (case reference: 10 A 2281/23 and 10 A 1477/23), the OVG ruled in favour of the owners in both cases. In each case, the requirement was that the design of the chosen solar unit had to be compatible with the historic listed status - in particular, by adapting the colour and the way it is placed within the roof structure. In the opinion of the court, the legal provision ushered in with the 2023 Renewable Energy Sources Act (Erneuerbare-Energien-Gesetz, EEG) - according to which when giving consideration to protected objects, renewable energy sources usually need to be treated as being in the overriding interest - also has an influence on the building preservation legislation of the Länder (Federal States). 

While it remains necessary to consider the individual cases, nevertheless, interest in the energy transition process will generally predominate. Refusing to give a permit would only be permissible in justified exceptional cases. The cases were specifically assessed as follows: 

  • Düsseldorf: The solar unit was only visible from limited viewpoints, it did not affect a single protected vista and did not impair the overall effect of the residential settlement.
  • Siegen: Even on the widely visible rooftop area the solar unit did not impair the protected visual appearance. The crucial factor was that the status as a historic monument was based on the ridge turret and not on the rooftop area.

Outcome

The rulings bolster the position of owners of historic listed buildings who want to contribute to the energy transition process. Solar units may be approvable even on protected buildings if their design and implementation is appropriate for the historic listed status.