HESS, Slovenia’s hydropower producer, has commissioned two solar facilities at the Brežice hydropower plant, bringing total photovoltaic capacity at the site to 15.34 MW. HESS describes the expanded facility as Slovenia’s largest solar complex. The new installations are named FEBR-D1 and FEBR-D2.
Together, FEBR-D1 and FEBR-D2 provide 9.34 MW, complementing the existing 6-MW FEBR-D3 solar plant, commissioned in 2023. The site’s total annual production is expected to reach approximately 17.4 GWh. The two new facilities are expected to generate around 10.5 GWh a year.
Solar generation alongside the Brežice reservoir
The new installations cover about 9.4 hectares of former sediment disposal areas beside the Brežice reservoir. Their location allows HESS to combine solar and hydropower generation. It also makes use of existing energy infrastructure and previously disturbed land.
When solar output is high, the operator may be able to conserve reservoir water for generation at a later time. This is subject to the hydropower plant’s operational constraints. The new solar facilities have separate grid connections.
Grid connections and project investment
FEBR-D1 supplies the Elektro Celje distribution network. FEBR-D2 connects to the ELES transmission system through existing Brežice hydropower infrastructure. Investment in the expansion exceeded €4 million.
Construction took slightly more than 14 months to complete. Earlier project preparation included amendments to local spatial plans and securing construction permits. These steps formed part of the development process.
Hybrid renewable development
The project illustrates an increasingly important renewable-development model in Southeast Europe: combining solar generation with existing hydropower assets, grid connections and industrialised land. Such hybrid sites can reduce permitting and connection risks. They can also allow more efficient use of transmission infrastructure.
