Croatia’s national transmission system operator (HOPS) has approved a transmission infrastructure blueprint for investment group Pantheon Atlas’ planned 1GW AI data centre campus in Topusko, which includes a 500MW solar PV project.
The planned 310-acre campus, located around 90km south of Zagreb with scope to expand to 450 acres, is designed for up to 1GW of total capacity and 800MW of usable IT load to Nvidia’s Gigawatt Scale AI Factory standards. According to Pantheon Atlas, the facility will be powered by an on-site 500MW solar plant and an 8,000MWh battery energy storage system (BESS).
Try Premium for just $1
- Full premium access for the first month at only $1
- Converts to an annual rate after 30 days unless cancelled
- Cancel anytime during the trial period
Premium Benefits
- Expert industry analysis and interviews
- Digital access to PV Tech Power journal
- Exclusive event discounts
Or get the full Premium subscription right away
Or continue reading this article for free
Pantheon Atlas said it is now pursuing a grid connection agreement, with construction expected to begin in early 2027.
The approved plans include more than €500 million (US$568 million) of transmission infrastructure, including 280km of new transmission lines, fibre-optic lines and a 400kV substation.
“Croatia’s largest-ever private investment is moving forward as a direct result of momentum from the unique partnership driving this project: Croatian expertise, US capital, world-class partners in Končar and Greenvolt and continued support from the Ministry of Economy of the Republic of Croatia and Hrvatska elektroprivreda (HEP Group),” said Mario Gudelj, Pantheon AI project director.
Pantheon said it will transfer the completed infrastructure to the Republic of Croatia for permanent ownership and operation, with the investment intended to strengthen the country’s electricity transmission network and address existing grid constraints.
The project will supply the planned AI data centre while opening grid access for more than 5GW of new renewable energy generation capacity that is currently constrained by transmission bottlenecks in Croatia.
Pantheon Atlas said the HOPS approval addresses what it described as a key barrier to large-scale data centre development in Europe: grid access. It also cited projections that data centre electricity demand in Central and Eastern Europe will grow three to four times by 2035, with no gigawatt-scale AI-optimised facility currently serving the region.
Project partners include Končar Group for the new substation, Dalekovod Projekt for transmission infrastructure design, and Parsec Lab for data centre design and engineering.
In April 2026, Pantheon Atlas announced plans to develop the €50 billion (US$58.5 billion) AI data centre. The company said construction of the Pantheon AI campus would begin following an initial €12 billion investment, with the facility expected to be fully operational in the first quarter of 2029.
Additionally, Spanish independent power producer (IPP) Greenvolt signed a letter of intent to build the project’s solar and storage assets.
