Slovenian state-owned utility HSE has started trial operation of the Prapretno 2 and 3 solar plants, expanding the site into the country’s largest operating photovoltaic complex and adding battery storage to manage variable output.
The completed complex has 9.8 MW of solar capacity and more than 17,900 modules. HSE has also installed a 7-MW/14-MWh battery, allowing electricity to be shifted between periods and providing additional grid support.
Prapretno 2 and 3 were built on land previously used for depositing ash and slag from a coal-fired power plant. The development is Slovenia’s first renewable project to receive co-financing from the EU Just Transition Fund.
The original 3-MW Prapretno solar plant was commissioned more than four years ago and was then Slovenia’s largest photovoltaic facility.
The two new phases transform the site into a hybrid generation and storage complex. HSE said the investment forms part of the redevelopment of former coal regions, where degraded industrial land can be reused without creating the land-use conflicts associated with some greenfield renewable projects.
The battery is a relatively small addition in capacity terms, but it marks an important change in project design: new solar generation is increasingly being paired with flexibility rather than connected as a standalone asset.
