A historic half-timbered house and a solar panel system on the roof—to many, this seems like a contradiction. Historic preservation is even frequently viewed as an obstacle to climate protection measures. The common argument is that it stands in the way of expanding renewable energy—and as a result, historic preservation laws are being amended, often accompanied by a weakening of historic preservation standards overall. But does this line of reasoning hold up to closer scrutiny?
In the public debate over historic preservation and solar panels, the impression of a fundamental conflict often dominates. A look at the numbers, however, puts this picture into perspective: Only 3 to 4 percent of the total building stock in Germany is designated as historic, and in North Rhine-Westphalia, the figure is as low as 1.5 percent. The actual debate over historic preservation and photovoltaic systems thus focuses far too often on this small segment of the building stock. Anyone who wants to make a tangible contribution to the energy transition through the expansion of solar power will therefore find far greater potential in the remaining, non-historic buildings. Narrowing the debate to the minimal contribution of listed buildings and thereby portraying them across the board as obstacles to the energy transition is a distorted view, especially given the expected impact. Where installation on the historic structure itself nevertheless reaches its limits, creative and legally sound solutions have long since been developed—ranging from alternative locations to new material innovations.
If installation on the historic structure itself is not possible
If there are serious reasons preventing the installation of a PV system on a historic building, this does not automatically spell the end for renewable energy. Alternative locations can often be found, such as on adjacent or neighboring buildings that are not listed as historic monuments. For example, the German Foundation for Monument Protection installed a PV system at its Bonn headquarters in this way.
Generally, a distinction is made between visual and acoustic impacts that may be caused by solar or wind power systems and that could prevent approval. The reason lies in the very purpose of historic preservation: to preserve the structure’s materials and appearance as completely as possible so that it can remain an authentic testament to its era. Added to this are conservation-related, structural, and technical hurdles—organic roofing materials such as thatch or wooden shingles, the limited load-bearing capacity of historic roof trusses (especially in church roofs), or the question of whether a roof surface should be fully utilized or only partially covered. The increased fire load posed by a PV system is another factor that can endanger historic buildings. Nevertheless, solar installations on historic buildings have been approved in many cases for years, often without being immediately noticeable.
Reversibility as a Guiding Principle
Preserving the original structure is central to the interplay between historic preservation and photovoltaic systems, as this is where a building’s most important historical significance lies. For any structural intervention—including PV installation—the impact must be kept to a minimum. Additive systems—which can be installed without significant loss of structural integrity and later removed without leaving any residue—are therefore preferable to integrated solutions that involve, for example, replacing roof tiles or slate. Historic buildings have withstood numerous changes over the course of their history; new technologies, by contrast, are comparatively short-lived. A historic building can withstand this change well, as long as reversibility and the preservation of the building’s substance are maintained. Any construction work on a historic building—including the installation of a PV system—requires approval under historic preservation laws. Many historic buildings are also subject to environmental protection measures that safeguard their appearance and sightlines—a consideration particularly relevant for the rooftops of historic old towns.
Changing Legal Framework
Some historic preservation laws now explicitly take renewable energy into account. For example, the North Rhine-Westphalia Historic Preservation Act states in Section 9, Paragraph 3, essentially states that a permit must be granted if it does not conflict with historic preservation concerns or if there is an overriding public interest, provided that climate protection and the use of renewable energy are given appropriate consideration.
Technological advancements are also making progress: Solar modules in matching colors are increasingly blending harmoniously into historic roofing, and solar roof tiles—in which the PV cells are integrated directly into the tile—could enable significantly better adaptation to historic buildings in the future when re-roofing is necessary anyway. Replacing integrated modules—whose service life is usually shorter than that of the roofing itself—remains technically challenging. The issue of disposal also remains unresolved: solar systems are still sometimes classified as hazardous waste, and according to expert estimates, several million metric tons of scrap modules could accumulate by 2030.
The portrayal of historic preservation and photovoltaic systems as irreconcilable opposites therefore does not reflect reality. Given that listed buildings account for only 3 to 4 percent of the national building stock, the true potential of the energy transition lies in the remaining building stock. For the remaining cases, alternative locations, technical advancements, and reversible solutions that preserve the building’s integrity offer viable ways to address both concerns.
Read more: Heritage preservationists and climate activists do not always see eye to eye.
