Berlin’s Schöneberg district is home to the Pallasseum, a listed residential complex from the 1970s housing around 2,000 people across 500 flats. Today, PASM Power and Solution GmbH, a subsidiary of Deutsche Telekom, together with Gewobag and the GASAG Group, celebrated the launch of the Pallasseum’s new, innovative heating system, which harnesses waste heat from a nearby data centre.

The project, which won the RealGreen Award in 2024, demonstrates that climate-friendly modernisation of listed buildings is possible without imposing additional costs on tenants. The concept uses surplus heat from a neighbouring Deutsche Telekom data centre on Winterfeldtstraße, providing a model for sustainable urban energy use.

Overcoming the challenges of listed buildings

Energy-efficient retrofitting of existing buildings, particularly those with protected status, is widely regarded as one of the greatest obstacles to Berlin’s heat transition. External insulation is often not feasible. The Pallasseum faced precisely this challenge. The commissioning of the waste heat system therefore sends a strong signal across the city: climate protection in existing buildings is achievable without altering the façade and without burdening residents financially.

The system was officially inaugurated in the presence of Dr Jochen Lang from the Senate Department for Urban Development, Gewobag CEO Markus Terboven, and GASAG CEO Matthias Trunk. The concept, developed by GASAG Solution Plus in collaboration with PASM, has been hailed as a prime example of urban synergies and a successful application of the Energy Efficiency Act (EnEfG).

How the system works

The technical solution is both efficient and ingenious. Low-temperature waste heat, below 30°C, is raised to 70–75°C within the data centre using a powerful water-to-water heat pump. This heat is then fed into the Pallasseum’s heating network via a 140-metre-long local pipeline, supplying approximately 500 apartments. A modern gas boiler covers only peak demand. Once fully operational, around 65 per cent of the building’s annual heat requirement is expected to be met by the waste heat system. Even before completion, the concept impressed experts and was awarded the RealGreen Award in the “Socially Acceptable Decarbonisation” category in 2024.

A model for Berlin’s climate goals

“Berlin has set itself ambitious climate targets, and the heat transition in existing buildings is the biggest challenge,” explains Dr Jochen Lang, Head of the Housing and Urban Renewal Department at the Senate Department for Urban Development, Construction and Housing. “The Pallasseum project is an outstanding example of how this transition can be achieved. It demonstrates that climate protection, monument preservation, and socially responsible housing are compatible. The partnership between Gewobag, GASAG, and Telekom sends a strong signal to the whole city.”

Christopher Mathea, Head of Technology Development at PASM Power and Air Condition Solution Management GmbH, adds: “For Telekom and PASM, the energy efficiency of our system-critical infrastructure is key. That’s why we are making waste heat from data centres usable at more and more locations. At the Telekom data centre here, we are transforming a by-product of our operations into a valuable resource for the neighbourhood. It’s a win-win for the climate, tenants, and Berlin as a digital location.”

Markus Terboven, Commercial Director of Gewobag, said: “Today is a good day for the tenants of the Pallasseum and an important day for climate protection in Berlin. We are keeping our promise: modernising our portfolio without placing an excessive financial burden on residents. This project shows that monument protection, social responsibility, and climate goals can go hand in hand when innovative partners such as Gewobag, Deutsche Telekom, and GASAG Solution Plus collaborate.”

Matthias Trunk, Sales Director at GASAG, commented: “The heat transition will not only be decided in new buildings, but above all in existing ones. The Pallasseum demonstrates how unused energy sources such as server waste heat can be integrated intelligently into existing systems. We at the GASAG Group are proud to have implemented this award-winning concept from the initial idea to today’s commissioning, making a real contribution to the decarbonisation of Berlin.”

The Pallasseum project is now being recognised as an important model for implementing the Energy Efficiency Act (EnEfG) and for the decarbonisation of existing buildings across Germany.

The initiative has been funded by the Federal Republic of Germany through the Federal Ministry for Economic Affairs and Climate Protection, based on a resolution of the German Bundestag.