Slovenia is set to take a major step in renewable energy with a new floating solar project led by the state-owned power company Holding Slovenske Elektrarne (HSE). The 140 MW Druzmirje floating solar power plant will occupy up to half of Lake Druzmirje, a body of water created from decades of lignite mining near Sostanj in northern Slovenia. 

With an estimated investment of around $116.6 million, the project will be financed through a combination of HSE’s own resources, loans, and support from the European Union’s Just Transition Fund. 

HSE will retain full ownership, with operations managed by one of its subsidiaries and an initiative poised to become Slovenia’s largest solar project and one of Europe’s biggest floating solar installations.

Plant expected to power 35,000 households annually

According to Simon Cizmek, project manager for the floating solar plant, work is currently underway on spatial planning activities, with the decree of the spatial plan expected to be issued during the fourth quarter of this year. 

Cizmek confirmed that agreements with local authorities are currently underway, expressing optimism that the project’s financial and social benefits will be shared with the local population in various ways, pv magazine reported.

Details published on the HSE’s website confirm that once the PSE Druzmirje floating solar plant is completed, the lakeside area will be transformed into a recreational and social space for the community, combining renewable energy development with enhanced public amenities.

Construction is expected to begin by the third quarter of 2026, with the plant scheduled to start producing electricity in the first quarter of 2027. Once operational, PSE Druzmirje is projected to generate up to 140 GWh annually, enough to power around 35,000 Slovenian households. The project is poised to become Europe’s largest floating solar installation, surpassing the current record held by a 74.3 MW array in France, inaugurated in June 2025.

Large-scale solar still emerging in Slovenia

PSE Druzmirje is currently Slovenia’s largest solar project under development. The country’s solar market remains mostly focused on residential and commercial-and-industrial (C&I) installations, with utility-scale projects still in the early stages. 

The development of PSE Druzmirje represents a step toward larger, grid-connected solar projects and reflects the gradual growth of Slovenia’s renewable energy capacity. It may also serve as a reference point for future utility-scale solar initiatives in the country.

By mid-2025, Slovenia’s total solar capacity had reached approximately 1.5 GW, following the addition of 85 MW in the first six months of the year. In comparison, the country installed 298 MW of solar capacity in 2024 and 400 MW in 2023, reflecting a steady expansion of its photovoltaic sector over recent years.

Earlier this year, the Slovenian government approved a spatial plan for a 30 MW ground-mounted solar project, marking the country’s largest of its kind to date. The project is being developed by Dravska elektrarna Maribor, a subsidiary of the state-owned power company HSE, which continues to expand its footprint in Slovenia’s renewable energy sector.