A MAN Energy Solutions 30MW (8,530TR) CO2 (R744) heat pump installed in a district heating plant in Esbjerg, Denmark, has been successfully commissioned and is delivering heat to 25,000 homes, according to the manufacturer.
The district heating plant, which is equipped with a second 30MW CO2 heat pump that is not yet activated, replaces a recently decommissioned coal-fired combined heat and power plant. The district heating plant is operated by Danish utility DIN Forsyning and will supply 280,000MWh of heat annually to homes in Esbjerg and the nearby city of Varde, which have populations of 72,000 and 13,000, respectively. The project, first announced in 2023, is expected to reduce emissions by 120,000 metric tons of CO2e annually.
“From now on, all our customers in Varde and Esbjerg will benefit from district heating directly sourced by the North Sea,” said Helle Damm-Henrichsen, Managing Director of DIN Forsyning. “This achievement is not only transformative for DIN Forsyning but also a major step forward for the climate.”
Esbjerg is located on the west coast of Denmark, and the 30MW unit sources heat directly from the North Sea and is powered by electricity from a nearby wind farm, according to MAN. The heat pumps operate in tandem with a newly installed 60MW (17,060TR) boiler that uses “sustainable wood chips,” per MAN. A 40MW (11,373TR) electric boiler plant has also been installed to serve peak demand and to back up the main system.
System specs
Raymond Decorvet is a Senior Account Executive at MAN, which is headquartered in Augsburg, Germany, and also manufactures other industrial energy systems. He shared details about the installation during a presentation at the ATMOsphere (ATMO) Europe Summit 2024. The event was held in Prague, Czech Republic, November 25–26 and was organized by ATMOsphere, publisher of NaturalRefrigerants.com.
Each heat pump is powered by a single hermetically sealed oil-free inline centrifugal compressor that uses magnetic bearings. Temperatures in the North Sea range from 1–18°C (33–64°F), with the water heated to 70–90°C (158–190°F) for use in the district heating network. The system intakes 4,000L (1,056gal) of seawater per second and is equipped with 40,000m³ (1,412,586ft³) of thermal storage capacity.
“We can achieve a COP of 3.3 in wintertime using this cold water,” said Decorvet, whose presentation noted that the system’s summertime COP was 4.0.
During his presentation, Decorvet said that the system was up and running shortly after being fully charged and added that the district heating plant’s second heat pump should come online in the next few weeks.
“Last week, we charged the system, and a day later we achieved 30MW of thermal output at 90°,” said Decorvet. “We’ll do the same for the next heat pump in two or three weeks.”
Grid balancing
In addition to serving the Esbjerg district heating network, Decorvet said the MAN CO2 heat pumps can also help balance the local power grid due to their ability to ramp up and down their power output by 8MW within 30 seconds. Wind, solar and other renewables make up 14.3% of Denmark’s energy mix, and along with supply-side fluctuations, the intermittent nature of green power sources can cause sudden imbalances in the grid.
The Esbjerg MAN CO2 heat pump can take excess power from the grid and store it in the form of hot water or quickly ramp down output to return power to the grid when supply dips.
“Our compressors have an electricity input of up to 16MW, and we can run them at 50% part load,” said Decorvet. “We could even run the system at 20% part load just to increase the grid-balancing capabilities. This is a new milestone in heat pumps.” Despite its size, Esbjerg is not MAN’s biggest district heating project in Denmark. The coastal city of Aalborg is currently retrofitting its district heating plant with four water-to-water CO2 heat pumps totaling 177MW (50,329TR), with the system expected to come online in 2027.
“This is a new milestone in heat pumps.”
Raymond Decorvet, Senior Account Executive at MAN Energy Solutions
