Danish port city receives first cross-sectoral ETES Heat-Pump system from MAN

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Visualisation of the new ETES heat-pump, district-heating plant in Esbjerg, Denmark.[/caption]

Danish multi-utility company, DIN Forsyning, commissioned MAN Energy Solutions to supply two (Electro-Thermal Energy Storage) ETES heat-pump systems. The ETES systems will be installed in a new district heating plant based on the operating principle of a heat pump – but on a large, industrial scale. With an overall heating capacity of 50 MW, the plant will supply around 100,000 local inhabitants with approximately 235,000 MWh of heat annually. The goal is to decarbonize the heat supply using ETES technology.

The location at the Port of Esbjerg will enable the use of renewable power from nearby wind farms and seawater as a heat source for the generation of heating energy. The new district-heating plant will thus guarantee an emission-free alternative to the city’s current, coal-fired power plant, which at present provides approximately half of Esbjerg’s district heating and is scheduled for closure by April 2023.

ETES technology enables the exploitation of excess power from renewable energy sources, which will make more efficient the production from wind and solar energy. In addition, the operational flexibility of the heat-pump solution makes it possible to generate electrical balancing power in the short term, and therefore to maintain balance on the grid.


The HOFIM motor-compressor is at the heart of MAN’s ETES Heat Pump system.[/caption]

The key, innovative feature of ETES technology is the use of toxicologically and environmentally safe CO2 as a refrigerant for the entire system cycle. The CO2-based heat-pump plant in Esbjerg will be the largest of its kind ever used in the world.

The scope of supply for the project in Esbjerg covers the entire heat-pump system, including the heat exchangers, the piping for the CO2 and seawater cycles, the water pumps as well as the electrical infrastructure provided by ABB Switzerland and ABB Denmark. The core element is represented by two oil-free hermetically-sealed HOFIM motor-compressor units with integrated expander, which are developed, produced and tested by MAN Energy Solutions in Zurich (Switzerland). The absence of the dry gas seal system and the complete oil system as well as the use of a high-speed motor and active magnetic bearings results in an emission-free compression system with a small footprint.

The ETES heat-pump system is a version of the electrothermal energy-storage system, called MAN ETES, which was developed by MAN Energy Solutions in cooperation with ABB Switzerland. The basic principle of the technology is the conversion of electrical energy into thermal energy, which is stored in the form of hot water and ice in insulated reservoirs. The electrothermal process not only allows the distribution of the generated heat and cold to users according to demand and margins, but also offers the option of converting it back into electricity as an additional usage variant.

The energy-storage solution is suitable for a wide range of applications. MAN Energy Solutions is currently examining the possible implementation of the technology in the German state of North Rhine-Westphalia (NRW) as part of a funding program with project partners Rheinisch-Westfälische Technische Hochschule (RWTH), Aachen University and Stadtwerke Aachen Aktiengesellschaft (STAWAG). The study will examine the necessary requirements for the construction of an electrothermal energy storage facility with a capacity of up to 7 MW in the Aachen area.