Source: pv magazine

The battery energy storage system is the first phase of a 315 MW/760 MWh system that is being developed alongside 238 MW of solar under Bulgaria’s largest hybrid power project to date, due for completion next year.

By Patrick Jowett

Oct 14, 2025

Vienna-based independent power producer Renalfa IPP has commissioned the first phase of a large-scale battery energy storage system (BESS) in Bulgaria.

The company has brought online 65 MW/260 MWh of a planned 315 MW/760 MWh battery energy storage system (BESS) as part of the Tenevo Hybrid Renewable Project.

Located in southeastern Bulgaria, the hybrid project is being developed by Tenevo Solar Technology, a joint venture company between Renalfa IPP and Danish developer Eurowind Energy. Chinese energy storage company Hithium and Chinese power solutions provider Kehua are supplying the BESS technology, while Bulgarian developer Solarpro is acting as project manager.

Once completed, the Tenevo project will encompass a 238 MW solar site alongside the 315 MW/760 MWh BESS and 250 MW of wind turbines, making it Bulgaria’s largest and most complex hybrid energy storage project to date. It is due for completion early next year.

The project is financed by The European Bank for Reconstruction and Development and Raiffeisen Bank International AG.

In August, Eurowind Energy announced the first 69 MW of the 238 MW solar farm had come online.

According to a statement from Renalfa, the first phase of the BESS is already one of the largest co-located battery storage systems in Europe and takes its energy storage capacity in operation to in excess of 1 GWh.

The company, which is active in Bulgaria, Hungary, North Macedonia and Romania, also claims to have over 1 GW of projects in the late stages of development, as well as a wider project pipeline in excess of 4 GW.

Bulgaria inaugurated a 124 MW/496.2 MWh BESS in May, billed as the largest in the European Union to date. The country’s Ministry of Energy has since launched a public consultation on a new subsidy program targeting 1.9 GWh of standalone storage capacity.

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