55 MWh battery storage system goes live in Bulgaria

Billed as the largest operating battery energy storage system in Bulgaria to date, the 25 MW/55 MWh facility, developed by Austria’s Renalfa IPP, came online at the start of the month.

Vienna-based developer Renalfa IPP has started commercial operation at its 25 MW/55 MWh battery energy storage system (BESS) located in the city of Razlog, southwestern Bulgaria.

The system, which is connected to the transmission network and located alongside a 33 MW solar plant, successfully went live at the start of the month. Renalfa IPP claims the facility is the largest operating BESS system in Bulgaria and one of the first of such scale in Eastern Europe.

The facility is being managed and optimized by KER Toki Power, a fully digital Bulgarian electricity trader. The system participates in capacity and balancing markets via the trader’s platform, providing automatic Frequency Restoration Reserve (aFRR) and manual Frequency Restoration Reserve (mFFR) services to the grid.

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Nick Antonov, a spokesperson for Renalfa IPP, said the project marks the start of the company’s hybridization of over 1 GW of renewable assets either in operation or in construction. He added the company is about to introduce similar solutions to its other wind and solar assets in the region, including in Hungary and Romania.