Bulgaria to start repairing Chaira HPP in early 2024

Intensive negotiations are underway with the original manufacturer to restore the first turbine, which was shut down as a precaution due to identified damage to related equipment, a condition detected before the rehabilitation efforts began, the energy ministry said in a press release on Thursday.

The repairs of second and third hydro units will take twelve months each, with the works needing to be carried out in stages due to the technical specifics of the plant. As for the fourth turbine, the repair period will take 36 months after signing an agreement with a selected contractor. Documents are being finalised before opening a public tender to pick a contractor, the ministry added.

The fourth turbine went out of order in March 2022. The ministry has received a report from Swiss engineering consultant AFRY, which analysed operational and rehabilitation activities at the facility, establishing that material fatigue was the cause for the unit's failure.

With the project started in 1982, state-owned HPP Chaira was built with an installed capacity of 864 MW in generating mode and 772 MW in pumping mode, with four reversible Toshiba-made Francis pump-turbines. The facility is owned by the National Electricity Company (NEK). Unit 1 and 2 became operational in 1995, while the other two units were switched on in 1999.

Rehabilitation of the pump-storage plant, which is part of the Belmeken-Sestrimo hydro power complex in the Rila mountain, began in 2019 after an emergency shutdown the year prior. The total budget was 37 million euro ($40.3 million), with 70% of it coming from the EBRD-run Kozloduy International Decommissioning Support Fund (KIDSF) and the balance of 30% coming from NEK.

In December 2022, NEK received an extension to the KIDSF grant in order to complete the overhaul of hydro power-generating facilities.

Last month, NEK reported a 25% annual fall in electricity output from its 31 hydropower plants, to 1,522,985 MWh, as a result of insufficient rainfall.

($ = 0.9177 euro)