Summary
- Sesterce proposes more than €10bn of investment, with a 200MW first phase and eventual 600MW campus capacity.
- The Kaipola redevelopment would reuse industrial infrastructure, with Elenia identifying an existing high-voltage network connection.
- The developer has announced renewable generation, water conservation and community funding commitments, subject to future implementation.
Sesterce plans to invest more than €10 billion in an AI data centre campus at the former Kaipola paper mill in Jämsä, Finland, beginning with a proposed 200MW first phase and expanding to 600MW in a second phase.
The French infrastructure company announced the proposal on 8 October and says work on the first phase is intended to begin during 2026. Its longer-term ambition exceeds 1GW across Finnish industrial sites, rather than at Jämsä alone. These figures describe planned development capacity; the announcement does not establish that the full campus has planning permission, financing or commissioned electrical supply.
Sesterce says an anchor customer has already committed workload capacity. It has not identified that customer or disclosed the contractual volume, so the commercial commitment cannot be equated with confirmed availability of 600MW of operating computing capacity.
Reusing the Kaipola industrial site
The planned campus would repurpose a paper mill that closed in 2021, retaining the site’s industrial function while changing what the infrastructure supports. Sesterce identifies its existing power network, water systems, buildings and logistics links as elements it intends to make use of. The reuse opportunity is substantial, but equipment designed for paper production does not automatically meet the continuous electrical and thermal demands of dense AI systems.
Kaipola Green Port owns the former mill site, according to contemporaneous Finnish reporting, which says negotiations over selling the site to Sesterce are underway. The status of that prospective purchase is a further distinction between the announced investment intention and a completed development transaction.
Jämsä’s mayor, Jori Reijula, welcomed the possible employment and investment while stressing that the project must progress from plans into implementation and satisfy applicable requirements. The city has not described the announcement as a substitute for planning and permitting decisions.
Elenia, the local electricity network company, offers a more specific indication of initial infrastructure readiness. Its chief executive, Jorma Myllymäki, says Kaipola is connected to Elenia’s high-voltage network and that the existing connection provides a solid foundation for the first phase. That is narrower than a commitment that every later expansion phase has secured its grid connection.
Cooling and electricity commitments
Sesterce has pledged to enable one megawatt of newly built renewable generation in Finland for every megawatt consumed by the campus. The new generation would be added within ten years after the campus becomes operational. Only newly constructed generation qualifies under the company’s stated commitment, which is different from relying exclusively on certificates attached to pre-existing renewable supply.
The ten-year delivery period also matters. The commitment is not evidence that corresponding new generating capacity will be online on the first day the data centre draws power. Nor does adding an equivalent amount of nameplate generation capacity guarantee that renewable output will match the campus’s electricity use hour by hour. Delivery arrangements and annual reporting will be necessary to judge performance against the pledge.
The company’s cooling proposal uses a closed-loop liquid system supplemented by harvested rainwater and recycled water. Sesterce says drinking water will not be used for cooling. The announcement does not specify the full heat-rejection design, expected water volumes or operating temperatures, so a quantified water saving compared with another facility cannot yet be supported.
Cooling becomes a critical design issue when high-density accelerators transfer considerable amounts of heat into liquid circuits close to the chips. Whether that heat can be reused outside the campus depends on its temperature, the distance to customers and the equipment required to connect a receiving network. Sesterce says waste-heat opportunities are being examined, but it has not announced a completed heat offtake agreement.
The developer also describes controllable, flexible electricity consumption as part of its intended operating model. It has not published the range of load it could shift, which workloads would permit it, or the contractual arrangements with the grid operator. Flexibility should consequently be treated as a design ambition rather than an already demonstrated grid service.
Jobs, local benefit and delivery conditions
Sesterce forecasts approximately 2,000 construction jobs and around 300 operational posts once the campus is fully running. It intends to prioritise Finnish contractors and subcontractors during construction. Neither forecast describes employment already created; the construction workforce will depend on how much of the planned programme proceeds and when individual phases begin.
Upon commissioning, the company says it will establish a €10 million community fund, with projects selected by the City of Jämsä and residents. It also plans publicly accessible restaurants and education spaces, physically separated from secure computing operations. These are proposed campus commitments, not facilities currently available to local residents.
Sesterce says four campus commitments will be measured, independently audited and publicly reported each year. The company has not yet published operational performance against them because the site is not commissioned. The commitment to publish measurements would allow later scrutiny of renewable build-out, cooling water arrangements and community provisions as the project advances.
The immediate milestones are more concrete than the investment headline: completing the site transaction, obtaining necessary permissions, converting the initial high-voltage connection into a deliverable engineering programme, and funding and building the first 200MW phase. Only after those steps can the second phase and Sesterce’s wider Finnish gigawatt ambition be assessed as progressing towards operating capacity.
