The Chaira Pumped Storage Hydro Power Plant (Chaira PSHPP) was built in the Rila mountain range, about 100 kilometres (62 mi) southeast of Bulgaria's capital city, Sofia.

The power plant is equipped with four reversible Francis pump-turbines, each rated at 216 megawatts (290,000 hp) in the generating mode, and 197 megawatts (264,000 hp) in pumping mode.

Units 1 and 2 have been in operation since 1995, and at that time Chaira was the largest pumped-storage plant in southeast Europe with the highest head in the world for a single-stage pump turbine (690 metres (2,260 ft) generating and 701 metres (2,300 ft) pumping).

The pump-turbines and motor-generators were supplied by Toshiba, and three of them were manufactured under Japanese supervision in Bulgaria.

[2] Outflow from the Belmeken reservoir supplies the Sestrimo Hydro Power Plant