OnZero Signs Agreement with Helen to Supply Recovered AI Compute Heat to Helsinki’s District Heating Network

OnZero’s AI Heat Factory is expected to supply up to 525.000 MWh of heat annually to approximately 70,000 apartment homes in Helsinki, combining high-performance AI computing with efficient heat recovery.

Helsinki, 31 August 2026 – OnZero Finland Oy (“OnZero”), a subsidiary of Vienna-based OnZero Alpha Holdings GmbH, has signed an agreement with Helen Ltd (“Helen”), one of Finland’s largest energy companies, to connect an OnZero AI Heat Factory to Helsinki’s district heating network.

The facility is expected to supply approximately up to 525,000 MWh of heat annually – sufficient to meet the heating needs of approximately 70,000 apartment homes in Helsinki. Operations are currently scheduled to begin during next year.

The agreement represents an important milestone in the commercial deployment of OnZero’s AI Heat Factory design, which combines high-performance AI computing infrastructure with the recovery and productive use of the heat generated by computing operations.

“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.

Turning compute heat into a usable energy resource

OnZero’s AI Heat Factory is based on a liquid-cooled architecture designed around heat recovery from the outset. While conventional data centres frequently release the heat generated by their servers into the environment, OnZero’s systems are designed to capture up to 99% of compute heat and make it available at temperatures suitable for district heating networks.

Helen has been using waste heat from data centres in its district heating system since 2010 and contributes extensive experience in integrating recovered heat into Helsinki’s energy infrastructure. Each megawatt-hour delivered can reduce the need for fossil fuel-based heat in Helen’s system.

“Helen can utilise waste heat recovered from OnZero’s data centre in Helsinki’s district heating system. This provides a cost-effective way to reduce the need for combustion-based heat production while helping to ensure that district heating remains a competitive and attractive heating solution for customers in the future. Our goal is to phase out combustion-based energy production by 2040, and the utilisation of waste heat plays an important role in supporting this transition,” said Tuukka Toivonen, COO, Strategy and M&A at Helen.

Impact on the Environment

OnZero data centers are designed for zero on-site water consumption: heat is rejected to district heating networks rather than through evaporative cooling, so the internal closed-loop coolant is cooled without any water loss.

Where recovered heat replaces natural gas-based heat production, emissions reductions may amount to approximately 1,500 tonnes of CO₂ per MW of installed heat recovery capacity annually.

Reference project for further deployment

The design of OnZero’s AI Heat Factory is intended to enable deployment in locations where growing demand for AI computing capacity coincides with access to district heating networks or other users of recovered heat such as the manufacturing sector. The project is also expected to serve as a reference for the company’s planned expansion into additional European countries.

About OnZero

OnZero builds and operates liquid-cooled AI data centers called AI Heat Factories, offering colocation services to enterprises and hyperscalers requiring high-density compute infrastructure. Every facility is engineered around heat recovery from the ground up, capturing up to 99% of compute waste heat and delivering it as carbon-neutral thermal energy to district heating networks.

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

Further information: www.onzero.tech

About Helen
Helen Ltd is the market leader in Finland’s electricity sales, committed to making everyday life easier and more effortless for customers throughout the country. We are responsible for the production and distribution of district heating and district cooling in Helsinki, while also providing solutions for regional and renewable energy. We are systematically reducing our emissions by developing a smarter energy system, with the goal of achieving net-zero emissions and phasing out combustion-based energy production by 2040. A future where energy is clean and flexible.

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