Slovenian energy company HSE is developing a 140 MW floating solar project, with work currently underway on spatial planning activities. The solar plant is set to become Slovenia’s largest solar project and Europe’s largest floating solar array to date.

September 26, 2025 Patrick Jowett

Image: Holding Slovenske Elektrarne

Slovenia’s Holding Slovenske Elektrarne (HSE), a state-owned power generation company, is working on a 140 MW floating solar project.

The Družmirje floating solar power plant (PSE Družmirje) is set to cover up to half of the surface of Lake Družmirje, a lake formed by decades of lignite mining near the town of Šoštanj, northern Slovenia.

Simon Čižmek, project manager for the floating solar plant, told pv magazine that work is currently underway on spatial planning activities, with the decree of the spatial plan expected to be delivered during the fourth quarter of this year. A public consultation took place earlier this week.

Čižmek advised that the project, with an estimated Capex of around €100 million ($116.6 million), will be funded by HSE’s own funds, loans and support from the European Union’s Just Transition Fund. It will be owned solely by HSE and operated by one of its subsidiary companies, HSE SaŠa.

“The agreements with local authorities are underway, we are very positive on the outcome and hope to be able to see the financial and other benefits being shared with the local population, in all sorts of different ways,” Čižmek added. According to details on HSE’s website, the lakeside area will be turned into a recreational and social space for the local community once PSE Družmirje is constructed.

As HSE is a state-owned company, the project will be subject to EU public tenders. Construction works are currently planned to begin by the third quarter of 2026, ahead of a scheduled production date within the first quarter of 2027.

Once operational, it is anticipated PSE Družmirje will generate up to 140 GWh of electricity annually, comparable to the annual supply for approximately 35,000 Slovenian households. It is likely to become Europe’s largest floating solar project to date, an accolade currently owned by a 74.3 MW array in France that was inaugurated in June this year.

PSE Družmirje is also Slovenia’s largest solar project under development. The Slovenian market is dominated by residential and C&I-sized solar installations, with the utility-scale market still in its early stages of development. In May, the Slovenian government approved a spatial plan for a 30 MW solar project, the largest ground-mounted project to date. The project investor is listed as Slovenian energy company Dravska elektrarna Maribor, another of HSE's subsidiaries.

Slovenia’s cumulative solar capacity reached around 1.5 GW by the end of the first half of 2025, after 85 MW of solar were deployed across the first six months of the year. The country deployed 298 MW of solar in 2024 and 400 MW of PV in 2023.