Trbovlje, Hrastnik, 17 March 2026 – Almost four years after the start-up of the Prapretno Solar Power Plant 1, the construction of units 2 and 3, which will also be equipped with a battery energy storage system, is coming to an end. This is an important step towards the further transformation of the former coal mining region, a concrete step towards the energy transition of the Zasavje region and the enhancement of Slovenia’s energy resilience as a whole. The Prapretno SPP is also the first domestic energy project co-financed by the Just Transition Fund of the European Union.

Prapretno, a landfill situated in a depression between Trbovlje and Hrastnik, is an excellent example of a successful transformation of a coal mining region into a modern location for production of electricity from renewable sources. The area of a closed ash, slag and gypsum landfill was given a new development opportunity almost four years ago when the Prapretno Solar Power Plant 1 was commissioned, and now the construction of units 2 and 3 is already in the final phase. The estimated annual production after the start-up of the upgrade of the first unit, which will consist of almost 18,000 solar panels, is 9.8 GWh, which is comparable with the supply of some 2,000 households. The project includes a 7 MW battery storage unit with a capacity of 14 MWh, which will enable optimisation of the solar power plant production with the needs of the electricity system and the market, and contribute to greater stability of the electricity system. Once the construction is completed, the Prapretno SPP will be the largest solar power plant in Slovenia.

The progress of works on the Prapretno SPP project, on which the installation works are well underway, was viewed today by mag. Bojan Kumer, Minister of the Environment, Climate and Energy, Dr Jerneja Jug Jerše, Head of the European Commission’s Representation in Slovenia, mag. Marko Koprivc, State Secretary at the Ministry of Cohesion and Regional Development, and the Mayors of the Municipalities of Hrastnik and Trbovlje, Marko Funkl and mag. Zoran Poznič in the company of the management of the investor, Dr Tomaž Štokelj, Chief Executive Officer of HSE, and Uroš Podobnik, Chief Operating Officer of HSE.

Upon the occasion, Minister Kumer underlined the importance of the Prapretno project for a fair energy transition, “Prapretno is more than a successful infrastructure project and a strong symbol of a fair transition. More than 8.7 million tonnes of fly ash, slag and gypsum from the Trbovlje Thermal Power Plant was deposited in this area between 1968 and 2014, and today we are looking at an example of how such an area can be transformed into an environmentally friendly energy location.” The Minister particularly emphasised the significance of cooperation in the green transition, “Today’s visit is also invaluable in terms of confirmation of the cooperation between the local environment, the state, the business sector and the European Union. Such partnerships will determine how successful we will be in the green transition in the coming years.”

The Prapretno Solar Power Plant is the first domestic energy project to be developed with the help of resources from the Just Transition Fund of the European Union (JTF). On the occasion, Dr Jerneja Jug Jerše, Head of the European Commission’s Representation in Slovenia, said, “Today, Europe is faced with a serious challenge. Electricity prices are too high. This affects people’s living costs and the competitiveness of our economy. To this end, the energy transition must be accelerated. We need an energy system that is clean, affordable, resilient and European. The Prapretno SPP 2 and 3 project is part of this transformation. It is proof that former coal mining regions can also play an important role in the development of clean energy and the realisation of European climate objectives.”

The Ministry of Cohesion and Regional Development, responsible for the management of European cohesion funds, also contributed to the success of the Prapretno SPP 2 and 3 project. Mag. Marko Koprivc, State Secretary at the Ministry, said, “The Prapretno Solar Power Plant project is a concrete example of the just transition being realised in practice. New energy infrastructure is being constructed in the area of the former ash and slag landfill, giving this brownfield site a sustainable development role. The project is co-financed from the Just Transition Fund by means of which we support projects in the Zasavje region with three key objectives: creation of new jobs and economic diversification; promotion of clean energy and energy conversion, and renovation of degraded sites to obtain new development roles. The Prapretno Solar Power Plant project very clearly combines all of these objectives and contributes to a joint vision: to help Zasavje evolve from a coal mining region into a region of innovations, new technologies and sustainable energy.”

As a strategic energy location, Zasavje’s role is becoming increasingly more important in the decarbonisation of Slovenia. For a number of years, the Municipalities of Trbovlje and Hrastnik, which share the Prapretno SPP, have been an excellent example of constructive cooperation when siting energy facilities in the environment and accelerating the green transition. Marko Funkl, Mayor of the Municipality of Hrastnik, highlighted, “In Hrastnik, we have had many good experiences with the siting of solar power plants and the HSE company. We are thus certain that the current investment in the solar power plant and battery storage units will also be an example of good cooperation with the local community. At the same time, this will be one of the first examples in Slovenia of a certain proportion of the energy generated being returned to the local community at a more favourable price, enabling the HSE company to also set standards for other investors in Slovenia. Subsequently, Hrastnik is again reclaiming its position as one of the municipalities with the highest number of solar panels per capita in the country.” Mag. Zoran Poznič, Mayor of the Municipality of Trbovlje, continued, “Prapretno is one of the principal examples of how the sites that relied on energy for decades can be given a new development opportunity. Just transition is understood in Trbovlje as a chance to transform the knowledge, the environment and industrial heritage into modern and sustainable projects that will create new jobs and development potential in the local environment. The solar power plants project in Prapretno is a major step in this direction, as it shows that former energy sites can become a platform for new ideas and opportunities based on good cooperation between the state, the expert sphere and the local community.”

HSE is extending its good cooperation with the Zasavje municipalities to Zagorje ob Savi as well. There, too, what was once a brownfield site will be given a new purpose by the setting up of a solar power plant and a battery storage unit, thus continuing Slovenia’s green transition. Dr Tomaž Štokelj, Chief Executive Officer of HSE, added, “The construction of new renewable sources and energy storage facilities is particularly important in the light of the current geopolitical situation or recent developments in the world, which increase the uncertainty of gas and oil supplies, with the prices of these energy products becoming more and more unpredictable. Projects, such as the one in Prapretno, reduce Slovenia’s import dependency and increase the resilience of Slovenia’s electricity system and the state as a whole. The HSE Group, as the spearhead of Slovenia’s green transition, will continue to play a decisive role in this.”

After a completed public procurement procedure, the contract with the company, RIKO, celovite tehnološke rešitve d.o.o., was concluded on 3 September 2025 for the implementation of the design, supply, installation and start-up of the Prapretno Solar Power Plants 2 and 3 and the battery energy storage system. According to the investment documentation, the investment value amounts to EUR 10.85 million exclusive of VAT, of which EUR 4 million came from the EU Just Transition Fund.

The works are progressing in accordance with the timeline. The Prapretno SPP 2 and 3 construction site opened at the end of December 2025. The completion of works and the commencement of start-up and functional tests of the Prapretno SPP 2 and 3 are expected to take place between March and May 2026, and regular operation is scheduled for summer 2026 after the acquisition of the operating permit. The life span of the power plant is estimated at 30 years.

Public Relations and Marketing Communication Department of HSE