Largest Danish heat pump installation utilising surplus heat from data centre

Data centres produce large amounts of surplus heat, which today is largely wasted. Currently, Meta (formerly Facebook), Google, Apple and Microsoft are operating and/or planning or constructing centres in Denmark. Redistributing waste heat from these centres to the district energy system would play a vital role in the green transition and reduce the growing industry’s carbon footprint. Globally, data centres account for around 1% of final electricity demand, according to the International Energy Agency. Ensuring they are powered by renewable energy and exploiting their excess heat can lead to large carbon reductions.

With the ambition to phase out its coal-fired plant by 2025, Denmark’s third largest district heating company, Fjernvarme Fyn, has established Denmark’s biggest heat pump plant. The plant will recover 215,000 MWh of energy from Meta’s hyperscale Tietgenbyen data centre and redistribute the surplus heat to the district heating network of the city of Odense.

The project, called Tietgenbyen Energy Centre, will provide heat to more than 12,000 homes (in 2023), reducing the city’s reliance on coal, and supporting Fjernvarme Fyn’s further goal of providing 100% renewable energy by 2030.

Fjernvarme Fyn appointed Ramboll as Owner’s Engineer to design the heat pump installation and energy centre, handle related tender processes and manage construction and building contract work. Furthermore, Ramboll developed the operation strategy for the surplus heat recovery system and executed design and strength calculations of the chilled water pipe network.

A water-based above- and below-ground piping circuit transfers surplus heat from heat exchangers in the data centre to the adjacent heat pump installation. Here, large electrically driven ammonia heat pumps raise the heat temperature to 70-75°C, suitable for the city’s district heating network. Distribution pumps supply the recovered heat to the network.

The heat pump installation is the largest to date in Denmark and recovers surplus data centre heat at an unprecedented scale. The total heat production is approximately 45 MW, which goes directly into the district heating network in Odense.

A full-scale visitor centre is displaying the ground-breaking technology applied. Tietgenbyen Energy Centre was ready for operation in late 2019 and already in 2020, Fjernvarme Fyn started planning for an expansion of the system as part of its plans to phase out coal by 2025.

Using surplus heat from data centres in Denmark:

• In January 2022, a tax on using surplus heat was abolished by the Danish parliament for businesses that are certified by the Danish Energy Agency, vastly improving the business case to deliver low-carbon excess heat.
• Data centres can deliver large amounts of surplus heat if they are connected to the district heating network. The heat has a relatively low temperature, which must be raised by a heat pump before it can be used
• To ensure a viable business case, data centres must be located close to a district heating network. The bigger the data centre, the farther the energy can be transported
• The European Commission suggests that all data centres of more than 1 MW should perform a cost benefit analysis to investigate whether the surplus heat can be used in the district heating supply
• According to the Danish Data Center Industry, 63%of data centres plan to utilise their surplus heat in the near future.