Work on the 150MW (42,651TR) ammonia (R717)-based district heating plant in Cologne, Germany, has entered the main construction phase, with commissioning scheduled for 2028, according to manufacturer Everllence (formerly MAN Energy Solutions).
Although construction at the Cologne site has only recently begun, the plant’s three integrally geared ammonia compressors, which will be at the heart of the system, are already at an “advanced stage” of manufacturing, according to Everllence.
RheinEnergie, the regional utility provider, recently obtained permits to begin construction of the buildings and technical infrastructure at the site, where the heat pumps will use the Rhine River as a heat source. The permits include approval to extract water from the Rhine and a permit for the plant under Germany’s Federal Immission Control Act. A third permit allowing the system to return water “cooled by a few degrees” to the Rhine is in the final stages of processing, according to RheinEnergie CEO Andreas Feicht.
“With the transition into the main construction phase, Europe’s largest river-water heat pump is becoming reality step by step,” said Alexander Stöckler, Head of Sales for Tendering & Project Management in Everllence’s Power Segment. “As EPC [engineering, procurement and construction] contractor, we are responsible for implementation across all project phases and will ensure that the individual components and systems come together to form a high-performance and sustainable solution for Cologne’s future heat supply.”
The project: Three ammonia heat pumps, each with a heating capacity of 50MW, will extract low-grade heat from the Rhine, typically around 10°C (50°F), and use it to produce district-heating water at temperatures of up to 110°C (230°F).
- With a projected COP of 3, the €280 million ($322 million) heat pump project, subsidized by the German government and the EU, will supply heat to approximately 50,000 homes.
- Amid fluctuating energy prices, RheinEnergie will operate the large-scale heat pump when electricity is abundant and inexpensive, while relying on its existing gas- and steam-turbine plants to produce electricity and district heating when prices rise.
- Everllence’s PrimeServ digital service package will enable real-time monitoring to optimize operation at the Cologne plant.
The technology/production: Everllence’s integrally geared centrifugal compressor, housed in a single casing, can accommodate up to five pinions mounted on separate shafts and driven by a central bull gear, according to the company.
- “Unlike conventional single-shaft compressors, a multi-shaft integrally geared compressor allows each impeller to rotate at its most effective speed, improving performance and reducing energy consumption across different compression stages,” the company said.
- Everllence is producing the compressors’ gearboxes and some components for the Cologne project at its Berlin facility, with manufacturing of the remaining components and final assembly to take place in Oberhausen.
Growing experience: Other large-scale district heating projects involving Everllence heat pumps include two CO2 (R744) systems in Denmark and an ammonia system in the United States.
- In addition to the Cologne project, Everllence is currently constructing a 177MW (50,329TR) CO2 system in Aalborg, Denmark, that will use 2–3°C (36–37°F) seawater as the heat source. The installation consists of four 44MW (12,511TR) water-to-water heat pumps and will supply roughly one-third of the city’s annual heat production.
- In Boston, district energy provider Vicinity Energy is installing a 35MW (9,952TR) ammonia-based steam heat pump. Using the Charles River as a heat source, the system will produce roughly 50 metric tons of steam per hour and provide heating for more than 70,000,00ft2 (6,500,000m2) of building space, according to Everllence.
- In December 2024 Everllence commissioned a 30MW (8,530TR) CO2 heat pump at a district heating plant in Esbjerg, Denmark, for Danish utility DIN Forsyning. Using seawater as a heat source, the plant delivers heat to roughly 25,000 homes.
Quotable: “We are combining various generation technologies in such a way that we can leverage cost advantages and stabilize district heating prices in the long term,” Feicht said. “The utilization of ambient heat from the Rhine allows us to achieve considerable climate protection benefits compared to fossil fuel generation, saving at least 100,000 [metric] tons of greenhouse gases annually.”
“With the transition into the main construction phase, Europe’s largest river-water heat pump is becoming reality step by step.”
Alexander Stöckler, Head of Sales for Tendering & Project Management in Everllence’s Power Segment
