Summary
- Pantheon Atlas has secured grid approval for infrastructure linked to a proposed 1GW AI data centre campus in Topusko, Croatia.
- The project includes a 400kV substation, transmission lines, fibre routes, roads, on-site solar, and large-scale battery storage.
- The scheme shows how Central and Eastern Europe is moving into the AI capacity map through power-led campus development.
Pantheon Atlas has secured Croatian grid approval for the infrastructure behind a proposed 1GW AI data centre campus in Topusko, giving the project a clearer route through one of Europe’s hardest capacity constraints.
The approval from Croatian transmission system operator HOPS covers transmission and distribution infrastructure tied to the proposed development. The package includes more than €500 million of works, including 280km of transmission lines, fibre routes, access roads, and a 400kV substation in Topusko.
Construction is expected to begin in early 2027. Pantheon Atlas is targeting a campus with up to 1GW of total capacity and an estimated 800MW usable IT load, alongside 500MW of on-site solar generation and 8,000MWh of battery storage.
Power before property
The Croatian project is large enough to be read as an energy infrastructure scheme with data halls attached, rather than a conventional real estate development that happens to draw a heavy electrical load. Its delivery depends on high-voltage network works, substation engineering, grid transfer arrangements, storage, renewables, roads, fibre, and long lead-time electrical equipment.
That puts the HOPS approval close to the centre of the project, not on its margins. Many European data centre proposals still move through the market with land positions, customer demand, or broad renewable claims sitting ahead of detailed power delivery. A campus built around an 800MW usable IT load cannot proceed on that basis. Without a credible transmission route, the project remains a demand forecast rather than deliverable capacity.
Battery storage adds another layer. An 8,000MWh battery system could help smooth on-site renewable generation, reduce exposure to peak demand periods, support resilience, and provide flexibility to the grid. It does not remove the need for firm network capacity. For a development of this size, storage is part of the power architecture rather than a substitute for grid integration.
The same applies to the planned 500MW solar plant. On-site generation can strengthen the commercial and sustainability case, especially where it is backed by storage, but AI campuses require reliable power across the year and across the daily load profile. The electrical design must still deal with periods of low solar output, equipment failures, maintenance windows, fault response, and the behaviour of the data centre as a large industrial load.
Central Europe steps into the AI buildout
Topusko sits outside Europe’s established data centre hubs. That is becoming less unusual as AI demand changes site selection. Training workloads and some high-performance computing applications can tolerate locations farther from traditional enterprise and interconnection centres if power, fibre, cooling, land, and political support line up.
Central and Eastern Europe can offer larger land opportunities and, in some markets, more room to create integrated energy and compute campuses. Those advantages do not make delivery easy. Developers still face planning scrutiny, equipment supply constraints, grid engineering capacity, construction labour limits, and questions over how much national energy infrastructure should be organised around private digital load.
The proposed transfer of infrastructure ownership to the Croatian government also gives the scheme a wider public dimension. If the transmission buildout unlocks additional renewable generation that is currently constrained, the project could change more than the data centre market around Topusko. It could also reshape parts of the surrounding grid and renewable development pipeline.
The execution risk remains substantial. A 1GW campus with solar, storage, a 400kV substation, and hundreds of kilometres of lines will be exposed to permitting, procurement, financing, construction sequencing, and community acceptance. Transformers, switchgear, grid components, and specialist engineers are already difficult to secure across Europe.
Even so, the Croatian approval gives the project a stronger infrastructure footing than many headline AI campus proposals. It puts the power path in view before the data halls rise, and it shows how the next wave of European capacity may be shaped by grid engineering as much as by developer appetite.
