Data Centers Leverage Cooling to Heat Homes

Data center operators, both colos and hyperscalers, are seeing renewed interest in putting the excess heat generated from cooling data centers to provide nearby homes with an affordable resource: heat.

For an industry obsessed with cooling, it seems odd that heat would be the symbol of goodwill between data centers and the communities in which they operate. Right now, primarily Nordic countries leverage this data center heating opportunity to their advantage. With challenges in energy prices, due to global inflation, and lack of heating availability, partially due to the Russia-Ukraine War, data centers such as Equinix, QTS, and Digital Realty have stepped up to provide heating in some of the chilliest cities on the planet.

Data Centers Providing Energy Resources for the Grid

Data centers have been doing this on a small scale for more than a decade -- but sustainability efforts, as well as rising energy costs in Europe due to the Russia-Ukraine conflict, are lending new urgency to green energy supplies.

Rendering of Equinix’s future energy-returning data center facility in Paris.

In Finland, Equinix has been heating homes in Helsinki for more than 10 years, said Sami Holopainen, Finland managing director at Equinix. And the firm has plans to raise temperatures in their data centers to reduce energy costs.

Elisa, a Finnish data center operator that’s been carbon-neutral since 2020, works with Helsinki Energy to heat 1,000 one-bedroom flats, said Krister Palmen, head of network operations management, while Hyperco is working on two projects in Helsinki projected to heat 5,000-7,500 apartments per 10 MW of data center, said Ari Kurvi, chief development officer at Elisa.

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In the Netherlands, QTS Data Centers recently announced that its Groningen data center is already heating 5,000 homes, said J. D. Luycks, managing director for Europe.

Why Are Data Centers Providing Heat in Nordic Countries Only?

Nordic countries are in the lead because many major cities heat homes through a district heating system, a municipal utility like electricity or water. District heating covers 90% of Finnish cities, Kurvi said. It covers heating for 65% of Danish households, according to Henrik Hanse, CEO of the Danish Data Center Industry. Nearby data centers tap into the system using heat exchangers, using heat pumps to intensify the heat, and pipes to transport heat (typically as hot water) to the district heating system and then to homes.

Of note: If the district heating system can’t accept the data centers’ heat, those facilities must still use their cooling systems to expel the excess heat.

Related:Germany Wants to Reuse Data Centers’ Heat. No One Is Buying It

To connect to the district heating system, data centers have to invest in modifications to facilities. The district heating system or energy company may provide funds to retrofit a data center for heat provision.

The QTS WarmteStad project, in Groningen, the Netherlands, sends heated water to the city's district heating system and receives cooled water back. The district heating system sends heated water to houses and receives cooled water back.

Groningen, for example, is investing 60 million euros in the QTS heating project. But several operators said they were willing to make the investment to improve their sustainability. Operators also save on electricity, and some countries, such as Finland, have lower electric utility rates for data centers that reuse heat.

Some operators would like to provide heat for homes on the district heating grid in Nordic countries. But some can’t find a recipient. Greenergy Data Centers, near Talinn, Estonia, has yet to find a service provider because its data center, which opened less than a year ago, hasn’t reached enough IT load, said Uko Urb, marketing manager. Equinix is having trouble finding a German recipient, Holopainen said.

Expanding Beyond Nordic Borders

Increasingly, regions with district heating systems are looking to expand them, which could give data center operators additional options for using excess heat. What’s more, the European Union is implementing sustainability goals that put pressure on data centers to engage in sustainable operational models.

Digital Realty's ZUR3 facility in Zurich, Switzerland is expected to be part of a new district heating project in the municipalities of Opfikon and Rümlang, where the data center’s waste heat will be used to warm homes in the EnergieVerbund Airport City region.

Digital Realty, for example, is designing most of its European data centers using chilled water to more easily lend themselves to heat reuse, said Lex Coors, chief data center technology and engineering officer at Digital Realty.

Using excess data center heat for homes in regions without district heating systems is more challenging, but it’s possible if the data center is close to residences. In Frankfurt, Telehause Deutschland will provide its excess heat to 1,330 apartments under construction across the street by 2025, said Béla Waldhauser, CEO, Telehause Deutschland.