NextGrid Energy has commissioned BESS Sibenik, a standalone battery energy storage facility in Croatia with 60 MW of power and 120 MWh of storage. HOPS, Croatia’s transmission system operator, has contracted the facility’s full capacity for automatic frequency restoration reserve (aFRR) services since September. The services help restore the balance between generation and consumption when system conditions change.
At the IMPOL-TLM industrial complex in Sibenik, the facility uses Tesla Megapack XL equipment and connects to the 110 kV network. Its 120 MWh capacity allows it to deliver full output for two hours. Designed to respond quickly to system imbalances, the battery is not intended to operate solely alongside a solar or wind farm.
Investment and operating model
The project cost approximately 60 million euros. The European Bank for Reconstruction and Development invested 16.8 million euros in equity, alongside Raiffeisen pension funds, while IE-Energy also invested. The project was approved for grants of up to 19.8 million euros from the EU Modernisation Fund.
About 15 million euros of the grant funding approved for the project is expected to be used, as construction costs came in below initial estimates. BESS Sibenik is designed to generate market-based revenue from storage and ancillary services rather than rely on fixed power-purchase arrangements. Investors retain the commercial exposure, while the facility adds 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, participation in the balancing market and operating arrangements. The project’s commissioning takes battery investment in Southeast Europe beyond concept-stage development, while its economics will depend on balancing demand, contracting terms and market prices.
