ContourGlobal opens 500MWh BESS project in Bulgaria coal plant
Yusuf Latief
Posted on: 9 January 2026
Operating the energy storage system in an existing power plant opens access to an existing grid connection for the project
ContourGlobal has commissioned a 202MW/500MWh battery energy storage system (BESS) in Bulgaria, which is now fully operational and participating in day-ahead and intraday electricity markets.
The stand-alone plant is located within the Maritsa East 3 (ME3) coal plant complex, opening access to an existing grid connection.
The project marks one of the largest BESS projects in Bulgaria and Eastern Europe, according to ContourGlobal.
Two remaining operational coal units of ME3 TPP continue to supply electricity during periods of peak demand.
The project, by participating in both the day-ahead and intraday national markets, aims to support optimised power dispatch, improved balancing of electricity supply and demand, and the integration of renewable energy sources, while enhancing overall system stability and flexibility.
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ContourGlobal chief executive Antonio Cammisecra said: “The commercial operation of our 202 MW/500 MWh BESS plant represents a significant step forward for battery storage development in Bulgaria and underscores ContourGlobal’s ability to deliver large-scale storage solutions across different markets and technologies.
“We have built a sizeable presence in battery energy storage, with this project in Bulgaria representing a key contribution to our 3GWh portfolio of operating BESS projects.”
Cammisecra added that the project was led by local teams and supported by the coal power plant’s personnel who had been reskilled.
Bulgaria’s Minister of Energy, Zhecho Stankov, said the commissioning of the storage system "marks a decisive step in Bulgaria’s energy transformation.”
Stankov noted that such projects signify how innovation and existing industrial infrastructure can work together to strengthen grid stability, improve flexibility, and accelerate the integration of renewable energy sources.
The project is one of many in Europe that has seen BESS systems operate within existing infrastructure, such as old coal power plants or even nuclear power plants, for quick access to the power grid.
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Said Stankov: “By combining advanced storage technologies with a strategic location in one of our key energy regions, Bulgaria is sending a clear signal that is at the forefront of the energy transition in Southeast Europe.
According to ContourGlobal, The BESS facility’s advanced technical features allow it to provide advanced grid services.
It is equipped with the recent battery technology, including 110 battery skids supplied by BYD and 28 combined Power Conversion System (PCS) and Transformer units, converting direct current (DC) from the batteries into alternating current (AC) for the grid. This represents BYD’s largest project in Eastern Europe to date.
The new BESS facility progressed from Final Investment Decision to COD in less than nine months, with construction and commissioning completed in just seven months and installation finalised in October 2025.
ContourGlobal is now developing a second 202MW BESS on the same site as part of Phase II of a broader strategy to leverage the thermal asset site to develop an integrated renewable energy hub.
By doing so, the company aims to further unlock the strategic potential of Stara Zagora’s major energy hub while advancing additional hybrid renewable projects, including photovoltaic generation combined with battery storage solutions.
