Austrian AI data center developer OnZero Finland has signed an agreement with Finnish energy firm Helen to connect its AI data center in Helsinki, Finland, to the city’s district heating network.

The facility is expected to supply the heat network with up to 525,000MWh of heat annually, which the companies claim is equivalent to the heating needs of 70,000 apartment homes in Helsinki. Operations are slated to begin sometime next year.

The deal forms a crucial part of OnZero’s AI Heat Factory commercial deployment strategy. The design combines high-performance AI computing infrastructure with heat recovery technology. It is based on a liquid-cooled architecture, and the company claims it can capture up to 99 percent of the heat generated by the data center and make it available at temperatures suitable for district heating networks.

“We founded OnZero with a clear objective: to lower the cost of AI by combining high-performance AI infrastructure with the efficient recovery and productive use of compute heat. Our agreement with Helen demonstrates how this approach can work in practice – turning heat generated by AI computing into a valuable resource for Helsinki’s district heating network,” said Ali Siddiqui, CEO of OnZero.

OnZero also claimed that its data centers are designed for zero on-site water consumption, with heat rejected into district heating networks rather than through evaporative cooling, so the internal closed-loop coolant is cooled without any water loss. The company said that the project is expected to serve as a reference for the company’s planned expansion into additional European countries.

The company currently operates facilities in Kemijärvi and Kerava, Finland, and is developing new sites across the Nordic region and Europe. It is headquartered in Vienna, Austria.

Finnish firm Helen has signed several heat reuse agreements with data center firms. Most notably with colo giant Equinix, with the company signing heat reuse agreements in 2024 and 2022.