Published 2026-09-12 · Event 2026-08-31

Helen and OnZero sign a Helsinki heat agreement; 2027 start is a schedule, not delivery

On 31 August 2026 Helen said it had agreed with OnZero Finland Oy to connect waste heat from a new data centre to Helsinki’s district-heating network. Recovery is scheduled to begin in 2027. Once fully operational the facility could supply more than 500,000 megawatt-hours of heat a year, enough for around 70,000 flats. That is a Finnish offtake paper. It is not Stockholm Exergi and not a Swedish megawatt.

Helen’s 31 August 2026 notice is the dated utility source used here. It says Helen and OnZero Finland Oy have signed an agreement to utilise waste heat from a new data centre in Helsinki’s district-heating network. Recovery is scheduled to begin in 2027. A scheduled year is a target. It is not a delivery-start certificate and not a Swedish planning decision.

The volume sentence must keep its wording. Once fully operational, the facility could generate more than 500,000 megawatt-hours of heat annually, enough to meet the heating needs of around 70,000 flats. Could and around are Helen’s words. Megawatt-hours of heat are not IT load, not facility power and not a reserved Finnish or Swedish import. Adding this row to Falun, Horndal or Conapto’s Open District Heating page would invent a geography the notice did not publish.

Helen also writes a history sentence, not a new Swedish proof. The company says it has been integrating data-centre waste heat into Helsinki’s network and supplying recovered heat to residents since 2010. That is a Finnish operating claim about an existing practice. It does not name OnZero’s building, a temperature, a pipe diameter or a 2026 delivered megawatt-hour.

Named Swedish heat rows stay on their own papers. Falu Energi & Vatten’s pellet-drying sentence, GleSYS’s 1 October 2020 Falkenberg start, Conapto’s Exergi page and Google’s Horndal heat-readiness note are different issuers. Helsinki does not become their missing offtaker. OnZero does not become a Swedish landlord.

DataCenterSweden records 31 August 2026 as a Finnish municipal-heat agreement. No Swedish project identifier is attached. The next defensible update would be a later primary source that names a start of delivery, a measured volume or a different offtaker. Until then, 70,000 flats remain a Helen illustration of a 2027-scheduled Finnish contract.

Why it matters

A named city heat buyer is the strongest kind of reuse paper. It is usable only if 2027, could and 70,000 flats stay Finnish — and if no Swedish hall inherits the megawatt-hours.

What remains unknown

The notice does not name a street address, a temperature, a 2026 delivered volume or a Swedish offtaker.

Sources