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 support the restoration of balance between generation and consumption after system conditions change.
Reserve services and grid connection
The battery is located at the IMPOL-TLM industrial complex in Sibenik and uses Tesla Megapack XL equipment. It connects to the 110 kV network and can deliver its full output for two hours. Designed to respond quickly to system imbalances, it is not intended to operate solely alongside a solar or wind farm.
Project costs and funding
The project cost approximately 60 million euros. The European Bank for Reconstruction and Development invested 16.8 million euros in equity, while Raiffeisen pension funds and IE-Energy also invested in the project. It was approved for grants of up to 19.8 million euros from the EU Modernisation Fund.
About 15 million euros of the approved EU grant allocation is expected to be used, as construction costs were lower than initially estimated. BESS Sibenik is intended 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.
Development and operations
NGEN worked with NextGrid Energy as a technology and operations specialist. Development required solutions for a direct transmission connection, participation in balancing markets and operating arrangements. The project’s economics will depend on balancing demand, contracting terms and market prices.
