Renalfa puts into operation 25 MW BESS in Bulgaria

The project, connected to the grid and co-located with a 33 MWp photovoltaic (PV) plant, is the largest operating BESS system in Bulgaria and one of the first BESS of such scale in Eastern Europe, Renalfa IPP said in a press release.

The storage system was designed, installed and integrated into the grid by local firm Solarpro Technology, part of Bulgarian-founded Austria-based Renalfa Solarpro Group, while the main BESS components were supplied by Chinese energy storage products manufacturer Hithium and power solutions provider Kehua.

"This co-located utility-scale battery marks the start of hybridisation of our over 1 GW portfolio of renewable assets in operation and in construction. We are about to introduce similar solutions in the other wind and PV assets in the region, including Hungary and Romania," Renalfa IPP spokesperson Nick Antonov said.

The main objective of the storage system is to mitigate the PV profile risk of the generators, Antonov added.

The BESS is commercially managed and optimised by local electricity trader KER Toki Power. Through the trader’s aggregator platform, the system is part of the capacity and balancing market, providing aFFR (automatic Frequency Restoration Reserve) and mFFR (manual Frequency Restoration Reserve) services to the grid.

Renalfa IPP is a joint venture between Renalfa Solarpro Group GmbH and French infrastructure fund manager RGreen Invest. The company owns and develops PV, BESS and wind projects with joint capacity of some 2 GW in Bulgaria, Hungary, North Macedonia and Romania, with more than 455 MW already operational and over 550 MW under construction.