Slovenia to build largest floating solar plant

September 28, 2025

Slovenia is preparing to make a groundbreaking move in renewable energy with the launch of its largest solar project to date—a 140 MW floating solar power plant on Lake Druzmirje. The project, spearheaded by state-owned utility Holding Slovenske Elektrarne (HSE), will transform nearly half of the lake’s surface into a hub of clean energy production. Lake Druzmirje itself was formed from decades of lignite mining near Šoštanj in northern Slovenia, making the site a symbolic shift from fossil fuels to sustainable energy.

$116 million investment backed by EU just transition fund

With an estimated cost of $116.6 million, the project will be financed through a blend of HSE’s internal capital, loans, and support from the European Union’s Just Transition Fund. HSE will maintain full ownership, while one of its subsidiaries will manage operations once the plant is completed. The development is positioned not only as Slovenia’s largest renewable energy investment but also as one of Europe’s biggest floating solar installations.

Clean energy for 35,000 homes every year

According to Simon Cizmek, project manager of the floating solar initiative, spatial planning is currently in progress, with approval for the spatial plan expected by the fourth quarter of this year. Agreements with local authorities are also underway, ensuring that the project delivers economic and social benefits to the surrounding community.

Once operational, the PSE Druzmirje floating solar farm will generate up to 140 GWh of clean electricity annually, enough to supply 35,000 Slovenian households. Beyond energy production, HSE has confirmed that the lakeside will be redeveloped into a recreational and social space, offering both environmental and community benefits.

Construction is set to begin by Q3 2026, with electricity production scheduled to start in Q1 2027. Upon completion, PSE Druzmirje will overtake France’s 74.3 MW floating solar farm (inaugurated in June 2025) to become the largest floating solar project in Europe.

Slovenia’s solar market expands beyond rooftop installations

Although Slovenia’s solar energy sector has primarily focused on residential and commercial (C&I) systems, large-scale utility projects like PSE Druzmirje signal a major shift. By mid-2025, Slovenia’s installed solar capacity reached 1.5 GW, with 85 MW added in just the first six months of the year. This growth builds on 298 MW of new capacity in 2024 and 400 MW in 2023, highlighting a steady expansion of the photovoltaic sector.

Earlier in 2025, the Slovenian government also approved a spatial plan for a 30 MW ground-mounted solar project led by Dravska Elektrarna Maribor, another HSE subsidiary. Together, these developments showcase Slovenia’s commitment to scaling up grid-connected, utility-scale renewable energy projects and reducing reliance on fossil fuels.

A turning point for Slovenia’s renewable future

The PSE Druzmirje floating solar plant marks a critical milestone for Slovenia’s clean energy transition. As the country shifts from small-scale solar systems toward large, grid-integrated projects, this installation is set to become a model for future developments. By combining renewable power generation with community-oriented land use, Slovenia is positioning itself as a leader in sustainable innovation in Central Europe.