Bulgaria has reached another milestone in the restoration of the Chaira pumped-storage hydropower plant, as unit 3 has officially been cleared for commercial operation after successfully completing all regulatory and technical approval procedures.
The National Electricity Company (NEK) announced that the unit received its final operating permit following inspection by the state commission. The approval confirms that the rehabilitation works meet all technical, construction, and legal requirements, allowing the facility to return to regular service.
This certification marks the completion of the recovery process for unit 3 and represents another step toward the gradual restoration of HPP Chaira to full functionality. Inspectors confirmed that the refurbishment was executed according to approved engineering plans and in full compliance with applicable standards.
The HPP Chaira facility plays a crucial role in Bulgaria’s electricity system and the broader Balkan power market. As the largest pumped-storage hydropower plant in the region, it provides essential balancing and flexibility services that help stabilize increasingly dynamic electricity systems. The plant had been largely offline for several years following unsuccessful repair works that previously led to the shutdown of its generating units.
At the same time, NEK continues restoration activities across the remaining units. Work on unit 1 is currently being performed by Japan’s Toshiba Corporation under an agreed rehabilitation schedule, with completion expected in 2028.
Preparations are also underway for the recovery of unit 4, as the utility advances its broader program to fully restore this strategic energy storage and generation asset.
The return of additional capacity at Chaira is expected to significantly strengthen Bulgaria’s ability to balance renewable energy production, improve grid reliability, and enhance overall energy security across the region.
