Belmeken–Sestrimo–Chaira Hydropower Cascade

The Belmeken–Sestrimo–Chaira Hydroelectric Cascade (Bulgarian: Каскада „Белмекен-Сестримо-Чаира") is situated in the Pazardzhik Province, southern Bulgaria and is the largest and most complex hydroelectric complex in the country. Located in the eastern part of the Rila mountain range, the complex receives waters from the drainage basins of the major rivers Maritsa, Struma and Mesta. Its catchment area is 458 km².

It was constructed in stages between 1964 and 1999 and includes two gathering derivations, three reservoirs, two equalizers, two pumped storage hydro power plants and two hydro power plants. The PSHPPs and HPPs are Chaira, Belmeken, Sestrimo and Momina Klisura with a combined installed capacity of 1,599 MW, producing an average of 1,170 GWh annually. It is thus the third largest power producing facility in Bulgaria by installed capacity, following the Kozloduy Nuclear Power Plant (2,000 MW) and the Maritsa Iztok 2 Thermal Power Plant (1,620 MW). The generated electricity is lower compared to other power stations in the country, due to the diversion of water for the supply of Sofia and its intended usage to balance short-term consumption changes.