Bulgaria has expanded its electricity system with the commissioning of a large-scale battery energy storage facility at the Maritsa East energy complex, one of the most significant storage projects in southeastern Europe. The installation was deployed at the site of TPP Maritsa East 3, leveraging existing grid infrastructure in the Stara Zagora region to accelerate implementation and reduce overall system costs.
Developed by ContourGlobal, the facility has an installed capacity of 202 MW and storage capability of 500 MWh, placing it among the largest standalone battery systems in Bulgaria and the wider region. It is already active on the country’s day-ahead and intraday electricity markets, while also delivering key balancing and flexibility services to the national grid.
Government officials say the project strengthens Bulgaria’s position as a regional stabilizer of electricity flows, combining advanced storage technology with legacy power infrastructure to enhance security of supply and support the transition toward a cleaner energy mix. The development also provides a new strategic role for traditional energy hubs such as Maritsa East, as coal-fired generation continues to decline.
Over the past year, Bulgaria has increasingly emerged as a balancing hub in southeastern Europe, offering cross-border support during periods of system stress. Battery storage has been a central pillar of this strategy, with national capacity already approaching levels comparable to the Chaira pumped-storage hydropower plant, nearing 5,000 MWh and expected to grow rapidly to at least 15,000 MWh by mid-year.
From an industrial and social perspective, ContourGlobal highlighted the role of local teams and the retraining of former coal plant workers, enabling existing skills to be redeployed in a modern energy environment and allowing the project to be completed within a tight schedule.
Financing was secured through European support mechanisms, with funds provided under the NextGenerationEU program as part of Bulgaria’s National Recovery and Resilience Plan. The battery facility covers around 25,000 square meters and includes 110 battery platforms along with 28 integrated power conversion units and transformers, ensuring stable and efficient integration into the transmission network.