Slovenian state-owned utility HSE has started trial operation of the Prapretno 2 and Prapretno 3 solar plants. The new phases expand the site into Slovenia’s largest operating photovoltaic complex. The project also adds battery storage intended to manage variable generation output.
The completed complex includes 9.8 MW of solar capacity and more than 17,900 photovoltaic modules. HSE has installed a 7-MW/14-MWh battery at the site. The storage system is designed to shift electricity between periods and provide additional grid support.
Site redevelopment and EU Just Transition 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 original Prapretno solar plant was commissioned more than four years ago.
At the time of its commissioning, the original 3-MW Prapretno facility was Slovenia’s largest photovoltaic installation. With the two new phases, the site operates as a hybrid generation and storage complex. HSE stated that the investment is part of redevelopment efforts in former coal regions.
Battery integration with new solar generation
HSE said degraded industrial land can be reused through the project without creating land-use conflicts associated with some greenfield renewable developments. The company described the battery as a relatively small addition in capacity terms compared with the overall solar build-out. It also said the design reflects a shift toward pairing new solar generation with flexibility rather than connecting it as a standalone asset.
The operational start follows completion of trial operation for the Prapretno 2 and Prapretno 3 plants, extending the existing photovoltaic footprint at the site into its current hybrid configuration.
