Energy-utility company, RheinEnergie, has commissioned MAN Energy Solutions to deliver a turnkey, riverine heat-pump plant at its Cologne-Niehl power-plant site. With a heating capacity of 150 MW, it will be Europe's largest fluvial heat-pump system supplying climate-neutral district heating to approximately 50,000 households in the Cologne metropolitan area. RheinEnergie is investing around €280 million in this flagship project.

The heat-pump system will utilize water from the Rhine as its energy source, operating with a natural refrigerant in a closed-loop system. Powered by electricity, the system will extract thermal energy from the river water and raise the temperature of the district heating water to up to 110°C, meeting the requirements of Cologne’s district-heating network. By replacing fossil fuels, the technology will enable annual savings of approximately 100,000 tons of CO₂; the heat-pump facility is expected to begin operation in 2027.

Andreas Feicht, CEO of RheinEnergie, said: “The large-scale heat pump in Cologne-Niehl is a cornerstone of our long-term strategy to decarbonize the heating sector. This initiative marks the beginning of a comprehensive program for sustainable heat supply. We are pleased to have found, in MAN Energy Solutions, a partner capable of delivering the project entirely from a single source, ensuring the successful realization of our vision.”

Dr. Uwe Lauber, CEO of MAN Energy Solutions, stated: “This pioneering project marks the first deployment of our innovative, large-scale, heat-pump technology in Germany. As the fourth-largest city in the country, Cologne is taking a leading role in showcasing how climate-neutral heat supply can succeed at a large scale. With our heat-pump technology, we are demonstrating how urban-heating systems can be transformed using sustainable energy sources – an essential step toward a greener energy future. Together with RheinEnergie, we are driving the heating transition forward and inspiring other large cities to adopt similar, climate-neutral solutions.”

Harnessing river water: how the large-scale heat pump works

The heat pump will use a thermodynamic cycle with a natural refrigerant to extract heat from the Rhine and transfer it to the district-heating network. In the evaporator, the liquid refrigerant absorbs thermal energy from the river water and evaporates. The gaseous refrigerant is then compressed, raising its temperature. This high-temperature heat is transferred to the district heating network via a heat exchanger, heating the water up to 110°C. After releasing its heat, the refrigerant cools and condenses back into a liquid state before returning to the evaporator to restart the cycle.

Mikael Adler, Head of Sales and Project Management Heat Pumps at MAN Energy Solutions, commented: “This order underscores the trust customers place in our technology and our ability to understand their specific needs. Our focus is on seamlessly integrating the heat-pump system into the existing district-heating network. We are already collaborating with district-heating providers on large-scale projects in Denmark, Finland, the USA, and now Germany. Together, we share a clear goal: to make heat-supply sustainable and climate-neutral.”

A turnkey solution for RheinEnergie

MAN Energy Solutions’ scope of supply includes the entire large-scale heat-pump system for the Cologne-Niehl site. This encompasses a building housing three large heat-pump units, the district-heating pump station, and a significant portion of the river-water and district-heating pipelines on-site. The package also includes all key components, such as compressors, condensers, heat exchangers, the control system, and the electrical infrastructure. MAN Energy Solutions is acting as EPC (Engineering, Procurement, Construction) contractor.

Alexander Stöckler, Head of Sales, Tendering & Project Management, Power Segment, says: “As EPC contractor, we will hand over a turnkey plant to RheinEnergie. Our EPC team at the Augsburg site already has extensive experience with projects and plants worldwide, which will now enable us to supply RheinEnergie with this complete solution from a single source. We are creating a blueprint that can also be transferred to other large-scale heat-pump projects in Germany, Europe and worldwide.”

Three integrally-geared compressors form the core of the technology and will be manufactured and tested by MAN Energy Solutions in Berlin and Oberhausen. Each compressor unit delivers a heating capacity of 50 MW, offering a compact design with high power-density to minimize space requirements. The system, powered by electrically-driven compressors, also enables rapid power-balancing within the electrical grid, supporting the integration of fluctuating renewable-energy sources.

The order also includes a Long Term Service Agreement with MAN PrimeServ, which will provide real-time monitoring, data analytics, and diagnostics of the compressor technology via MAN PrimeServ Assist.