Industrial strength CO2 based systems for Esbjerg

Image: Visualisation of Esbjerg’s heat pump based district heating plant

Danish multi-utility company, DIN Forsyning, has commissioned MAN Energy Solutions to supply a turnkey technology solution for heat generation using heat pumps based on the company’s ETES technology. The heat pumps will be installed in a new district heating plant, with an overall heating capacity of 50 MW, with the capability to supply approximately 235 000 MWh of heat annually.

The location, at the Port of Esbjerg, will enable the use of renewable power from nearby wind farms and 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.

“Esbjerg has very ambitious goals to become carbon neutral by 2030, and the new heat pumps will be an important element in achieving this. Esbjerg City is currently undergoing huge change and transforming from carbon based infrastructure towards a world leading position as a green city,” explains Jesper Frost Rasmussen, Mayor of Esbjerg.

“The deployment of the ETES heat pump systems from MAN Energy Solutions will help us to ensure an environmentally friendly and economically efficient heat-supply for the inhabitants of the city of Esbjerg. By decarbonising the heat supply, we are taking into account Denmark’s goal of phasing out coal while ensuring the environmental preservation of Denmark’s Wadden Sea, which is a UNESCO World Heritage Site,” explained Anders Linde, chairman of the Board of DIN Forsyning.

“The transition to a carbon-neutral world is at the core of all the actions we take today. This is why we are very proud to play a major role in the pioneering Esbjerg project as the provider of an innovative technology solution. The ETES heat-pump system is a climate-neutral alternative to traditional, large-scale heat supplies and will significantly drive the decarbonisation of the heating sector,” stated Uwe Lauber, CEO of MAN Energy Solutions.

Patrik Meli, senior vice president, managing director of MAN Energy Solutions Switzerland Ltd added: “Sector coupling is an essential key to a climate-neutral energy future. The growing share of renewable energy must also be harnessed outside of power grids in order to break through the extreme dependency on fossil fuels for heat and cold generation.”

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

The MAN Energy Solutions scope of supply for the Esbjerg project 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 consists of two oil-free hermetically-sealed HOFIM® motor-compressor units employing active magnetic bearings, with integrated expanders, developed, produced and tested by MAN Energy Solutions in Zurich.

Image: HOFIM motor-compressor

The ETES heat-pump system is a version of the electrothermal energy storage system, MAN ETES, which was developed by MAN Energy Solutions in co-operation 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 programme with project partners Rheinisch-Westfa¨lische Technische Hochschule (RWTH), Aachen University and Stadtwerke Aachen Aktiengesellschaft (STAWAG). The study is examining the necessary requirements for the construction of an electrothermal energy storage facility with a capacity of up to 7 MW in the Aachen area.