Coal power plant Maritsa East 3 plans to build solar plant, 200 MW battery system

Coal-fired power plant ContourGlobal Maritsa East 3, which operates only sporadically to ensure the stability of supply for Bulgaria’s power system, plans to repurpose the grid infrastructure of its units 1 and 2 for solar and battery storage capacities. Units 3 and 4 will remain on standby to generate electricity during peak demand periods in the summer and winter months, but the plant will need state support to cover maintenance and workforce costs.

Maritsa East 3 (Maritsa iztok 3), majority owned by the US-based ContourGlobal, plans to use the existing grid infrastructure, including transformers and switchgear, to speed up the green energy project within the complex, according to Vassil Shtonov, Executive Director of ContourGlobal Bulgaria.

The central element is a 200 MW standalone battery energy storage system (BESS), the largest of its kind in Bulgaria, which would improve the flexibility and stability of the national power system, Shtonov explained in an interview with Capital.bg.

The project involves a 200 MW standalone battery system and a solar power plant

The planned battery system at Maritsa East 3 was among 82 projects selected to receive a total of EUR 587 million in subsidies from Bulgaria’s Ministry of Energy in April this year.

“In parallel, we are considering the development of an additional hybrid solar park with a battery at the same site,” he said. This will allow for faster deployment of new clean energy capacity, while preserving all options for future use of the coal-fired plant and its original infrastructure, Shtonov added.

ContourGlobal plans to build 400MW to 500 MW of renewable energy capacity combined with batteries

ContourGlobal plans to invest hundreds of millions of euros to develop 400 MW to 500 MW of renewable energy capacity combined with storage systems, he said, adding that nearly half of this target is under construction or final approval. The company’s goal is to phase out coal by 2027 and achieve carbon neutrality by 2040, he stressed, recalling that Bulgaria’s targeted coal phaseout date is 2038.

Keeping coal plants on standby requires state support

Bulgaria’s state-owned National Electricity Co. (NEK) holds a minority stake in Maritsa East 3. After the plant’s 15-year power purchase contract with NEK expired in February 2024, it has only been able to operate on the free market for a few months a year. This year, units 3 and 4 were online from January to the end of March to maintain energy security.

Shtonov: Key coal-fired power plants should get a fixed amount from the state

However, to be on standby for system security, the plant needs to keep workers on the payroll even when it is not operating. For this reason, strategically important coal-fired power plants should receive a fixed amount from the state to cover ongoing personnel and maintenance costs, and then be switched on when necessary to protect consumers from sharp increases in electricity prices, as happened last year in July and November, according to Shtonov.