Public buildings very unevenly used for PV

28.11.2025

Source: E & M powernews

Viessmann Climate Solutions examines the development of solar installations on public buildings in Germany. Some cities are making significant progress, others are lagging far behind.

The municipal energy transition is progressing with great regional differences. This is shown by a recent analysis by Viessmann Climate Solutions based on data from the market master data register. One year after the Solar Package I came into force, the proportion of solar installations on public buildings across Germany is 0.9 percent. According to the company, this figure is down slightly compared to 2024, while the number of private installations continues to rise sharply.

Viessmann Climate Solutions ranks the cities according to the share of systems on municipal roofs in the total local solar expansion. Offenbach takes first place in the city comparison. There, systems on public buildings achieve a share of 3.07 percent. In Tübingen, the share is 2.8 percent, while Böblingen comes in at 2.76 percent. Both Baden-Württemberg cities thus maintain their positions in the top group. According to the analysis, almost all of the cities in the top 10 come from Baden-Württemberg or Hesse. According to the company, these regions are particularly active in using their public areas for solar energy.

Viessmann Climate Solutions names the city of Neuss in North Rhine-Westphalia as a clear climber. In 2024, it was still one of the laggards, but in 2025 it more than doubled the number of systems on municipal buildings. 30 new installations went into operation. The city thus improved its position in the ranking more than any other municipality in the period under review.

Berlin remains top

According to the analysis, a comparison between the federal states also shows different rates of solar expansion. Berlin defends its top position with a share of 1.26%, just ahead of Baden-Württemberg with 1.24%. Hesse follows with 1.17 percent. Brandenburg continues to bring up the rear. The public roofs there only contribute 0.47 percent to the total number of installations in the state.

While some regions are making significant progress with the expansion on their municipal buildings, according to Viessmann Climate Solutions, the figures also show that many cities are not keeping up with the pace of private installations. The percentage of public roofs is therefore falling, even though new systems are being built. According to the analysis, the potential remains untapped in several municipalities.

Grevenbroich and Pulheim, both in North Rhine-Westphalia, are particularly conspicuous. They each have a share of 0.21 percent and are therefore at the bottom of the urban analysis.

Municipal buildings could benefit more

Viessmann Climate Solutions classifies the results as an indication of a challenge for local authorities. Private households and companies are driving the expansion of solar energy. However, it is important for the public sector to involve its own buildings more in order to make a visible contribution to the energy transition and generate revenue. In many cities, there are still unused roof areas that are suitable for photovoltaics.

According to the company, the analysis shows that location plays an important role. Southern German cities are implementing solar energy on municipal roofs more frequently, while northern regions are usually experiencing slower growth. In addition, city states such as Berlin have structural advantages, as they have many public buildings and decision-making processes are often shorter.

According to Viessmann Climate Solutions, differences also arise because municipalities prioritize differently. Some rely on their own projects and municipal energy suppliers, while others primarily support private investment in photovoltaics. At the same time, the shortage of skilled workers in the electrical trade remains a limiting factor when it comes to implementing planned installations quickly.

Using the role model function

All those involved agree that the use of public roofs serves as a role model. Cities that invest more could also motivate local citizens to install their own systems or participate in energy cooperatives. According to the analysis, however, there are still many municipalities where such effects have not been achieved.

Viessmann Climate Solutions points out that further measures are needed to speed up approvals and building inspections. Some projects are delayed because coordination between different authorities takes a long time. According to the company, the municipal energy transition needs planning security and clear prioritization in order for development to progress in the area.

The results of the study "Solar expansion on public buildings: These German cities will lead the way in 2025" can be viewed on the Viessmann Climate Solutions website.

Author: Susanne Harmsen