Turning Data Center Excess Heat into District Heating in Kajaani, Finland 

Borealis Data Center has started transferring excess heat from its Kajaani campus in Finland to the local district heating network in May 2026, operated by the public utility Loiste Lämpö Oy, with Sweco supporting the project as its engineering, procurement and construction management partner. 

The partnership gives heat produced during everyday data center operations a valuable second use: warming homes and buildings across Kajaani. By connecting digital infrastructure with the city’s heating system, the project supports greater energy efficiency and a lower-carbon local energy mix. 

How Data Center Waste Heat Becomes District Heating 

Data centers generate heat continuously as servers and other equipment operate. At Borealis’ Kajaani campus, this excess heat is captured and transferred to Loiste’s district heating network instead of being released into the environment. 

As of June 2026, the campus is expected to provide approximately 3–5 MW of reusable heat. The system has been designed to scale, with a longer-term target of up to 10 MW as the campus and heat-recovery project expand. 

Loiste’s network has around 1,700 connections. Because many connections serve multiple properties, the network supplies heating to an estimated 2,000 or more buildings in the Kajaani area. 

For context, a 2 MW heat pump plant can produce approximately the same amount of annual heating energy used by 500 households. 

A More Efficient Use of Energy 

Recovering waste heat reduces the need to produce the same energy from other heating sources. It is a practical example of how data centers can contribute to the communities in which they operate while making better use of energy that has already been generated. 

Loiste aims to scale district heating produced with waste heat up to 80% of our annual production. 

Loiste CEO, Mika Paloranta, shares: 

“Our goal is flexibility in the production palette, and a new, different, low-carbon way of operating in district heating production. This reform affects everything we do and creates opportunities to optimize heat production more efficiently than before: we have put together a new kind of orchestra, which includes smart instruments that play together,”

Supporting the Local Community 

For Borealis, the project reflects a commitment to building strong connections between data center infrastructure and the surrounding community. 

From Borealis Leadership 

“We see ourselves as part of the local ecosystem,” said Björn Brynjúlfsson, CEO & Cofounder at Borealis Data Center. “Reusing excess heat allows us to support the Kajaani community in a practical way while improving how energy is used.” 

By supplying locally generated heat to the district heating network, the Kajaani campus can support both digital growth and the city’s changing energy needs. 

Open to Waste Heat Partnerships 

Borealis is open to working with additional heat off-takers and partners across its data center campuses. These collaborations can help extend the benefits of waste heat recovery to more businesses, public services, and local communities. 

Contact Borealis to discuss waste heat reuse opportunities. 

Frequently Asked Questions 

What is district heating, and how does Borealis Data Center's waste heat fit into it? 

District heating is a shared network that delivers hot water from a central source to homes and buildings across a city. In Kajaani, the network operated by Loiste Lämpö now includes heat captured from servers at the Borealis Data Center campus, giving everyday computing operations a second use instead of releasing that heat into the environment. 

How much heat does the Kajaani campus currently provide? 

As of June 2026, the campus is expected to provide approximately 3 to 5 MW of reusable heat, with a longer-term target of up to 10 MW as the campus and heat recovery project expand. For comparison, a 2 MW heat pump plant can produce roughly the same annual heating energy used by 500 households. 

Image source: Image via Sweco press release, “Hukkalämmön talteenotto käynnistyi Kajaanissa”