HSE begins trial operation at Prapretno 2 and 3
Slovenian state-owned utility HSE has started trial operation of the Prapretno 2 and Prapretno 3 solar plants. The start of commissioning expands the site into Slovenia’s largest operating photovoltaic complex. The project also includes battery storage designed to manage variable generation.
The completed installation combines 9.8 MW of solar capacity with more than 17,900 modules. HSE has installed a 7-MW/14-MWh battery at the site. The battery enables electricity shifting between periods and provides additional grid support.
Site redevelopment and EU Just Transition Fund co-financing
Prapretno 2 and Prapretno 3 were developed on land previously used for depositing ash and slag from a coal-fired power plant. HSE said the development is Slovenia’s first renewable project to receive co-financing from the EU Just Transition Fund. The new phases are part of a broader redevelopment of former coal regions.
HSE stated that using degraded industrial land can avoid land-use conflicts associated with some greenfield renewable projects. The original Prapretno solar plant, with a capacity of 3 MW, was commissioned more than four years ago. At the time, it was Slovenia’s largest photovoltaic facility.
Hybrid generation and storage configuration
The addition of the two new phases changes the site into a hybrid generation and storage complex. HSE described the investment as an expansion that pairs new solar generation with flexibility rather than operating it as a standalone asset. The battery capacity is relatively small in comparison with the overall solar buildout, according to the project design approach.
The trial operation of Prapretno 2 and Prapretno 3 therefore brings both solar output management and grid support elements under one configuration at the expanded site.
