Croatia’s BESS Sibenik, a 60 MW / 120 MWh standalone battery energy storage facility, has been commissioned in Sibenik, with HOPS contracting its full capacity for automatic frequency restoration reserve (aFRR) services since September. The arrangement gives the transmission system operator fast-response balancing capacity to restore the balance between generation and consumption after changes in system conditions.
Developed by NextGrid Energy at the IMPOL-TLM industrial complex, the facility uses Tesla Megapack XL equipment and connects to the 110 kV network. Its 120 MWh energy capacity provides two hours of storage at full output. The battery is designed to respond rapidly to system imbalances rather than operate solely alongside a solar or wind farm.
The project cost approximately 60 million euros. The European Bank for Reconstruction and Development (EBRD) and Raiffeisen pension funds each invested 16.8 million euros in equity, while IE-Energy also invested. The project was approved for grants of up to 19.8 million euros from the EU Modernisation Fund. Approximately 15 million euros of that approved funding is expected to be used, as construction costs were below initial estimates.
BESS Sibenik is intended to earn market-based revenue from storage and ancillary services, rather than rely on fixed power-purchase arrangements. The model leaves commercial exposure with investors while adding fast-response flexibility to the transmission grid. NGEN worked with NextGrid Energy as a technology and operations specialist.
Development required solutions for a direct transmission connection, balancing-market participation and operating arrangements. The commissioning moves battery investment in Southeast Europe beyond concept-stage development. The project’s performance will be watched for evidence of how balancing demand, contracting terms and market prices affect the economics of merchant-oriented storage.
