October 11, 2023
13 min read

MVV, Germany: Thousands of homes heated by river heat pump

Our heat pump uses Rhine water as a heat source and is one of the largest heat pumps in Germany, adding 20MWth to our existing ~1200MWth heat pump fleet.

Time-lapse of MVV Mannheim heat pump construction, Germany

The large-scale heat pump helps MVV to decarbonize district heating in Mannheim

Together with MVV we have built a large-scale heat pump plant in Mannheim. It uses river water as a heat source, helping to reduce the use of coal at the GKM plant. The new heat pump is the first step towards the goal of green district heating. MVV and the City of Mannheim is targeting to become CO2 neutral in the district heating production by 2030.

At the Mannheim site, the heat pump uses 7 MWe of electrical power from renewable sources to produce 20 MWt of thermal energy which is used to reheat the district heating return flow up to 99 °C.  From 2023 onwards, the facility is expected to supply heating for 3,500 households and save some 10,000 tonnes of carbon emissions per year.

The heat pump power plant consists of the following components

Basic principle of heat pumps

Heat pumps move thermal energy in the opposite direction of spontaneous heat transfer, by absorbing heat from a colder space and releasing it to a warmer one.

Heat pumps work like an inverted refrigerator, i.e. the river heat pump extracts a small part of the heat from the outside (here: Rhine water) and releases it again as heating energy for district heating. The Rhine water gets up to 25°C warm in summer and rarely below 5°C in winter. This makes it perfectly suited as a powerful heat source.

Learn more about the MVV Mannheim reference in Germany

District heating for 50,000 households – with heat pump technology from Finspong in Sweden

The heart of the heat pump plant is the compressor with gear, electrical motor, heat exchangers, and control system. The reliable heat pump is manufactured in our factory in Finspong, Sweden, and Siemens Energy is responsible for the full installation and commissioning. The technology has been proven for many years.

From the ground-breaking ceremony to the final heat pump plant

In spring 2022, the next step in our decarbonization journey began with the construction of our 18-metre-long, five-metre-high high-temperature heat pump on the site of the GKM coal-fired power plant. Commercial operation started in October 2023. It is one of five large-scale field trials - called 'Reallabore' in German - for large-scale heat pumps in Germany, using different heat sources such as industrial waste heat, geothermal or solar energy, river water, the sea, ambient air and others.

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