The Sayano-Shushenskaya Dam (, Sayano-Shushenskaya Hydroelektrostantsiya) is located on the Yenisei River, near Sayanogorsk in Khakassia, Russia. It is the largest power plant in Russia and the 12th-largest hydroelectric plant in the world, by average power generation. The full legal name of the power plant, OJSC [Open Joint-Stock Society] P. S. Neporozhny Sayano-Shushenskaya HPP [hydro power plant], refers to the Soviet-time Minister of Energy and Electrification Pyotr Neporozhny. the head of the power plant was Valery Kyari.
Description
The plant is operated by RusHydro. As of 2009, it was the largest power plant in Russia and the world's sixth-largest hydroelectric plant by average power generation. It provides more than a quarter of RusHydro's generation capacity. The plant operated ten type РО-230/833-0-677 hydro turbines manufactured at the Leningradsky Metallichesky Zavod, each with a capacity of 640 MW at head. The total installed capacity of the plant is 6,400 MW; its average annual production is 23.5 TWh, which peaked in 2021 at 29.4 TWh.
The station's constructions include the dam, a power plant building located near the dam, and an additional spillway which is under construction. The arch-gravity dam is high. It has a crest length of , crest width of , base width of and maximum head of . It consists of a solid left-bank dam long, a power dam long, a spillway dam long and a solid right-bank dam long. It is by far the larger of only two gravity-arch dams in Russia. Water pressure for the dam is approximately 30 million tons, of which 60% is neutralized by the dam's own weight and 40% is carried to rock on the bank
The dam is constructed to "safely" withstand earthquakes up to 8 on the Richter scale, and was recorded by the Guinness Book of World Records for the strongest construction of its type.
The dam supports the Sayano-Shushenskoe reservoir, with a total capacity of 31.34 km3, useful capacity of 15.34 km3 and surface area of .
Economic value
The station is the largest one contributing to peak consumption in the Unified Energy Systems of Russia. More than 70% of generated electrical power goes to Rusal's four smelters in Siberia.
In years of heavy rainfall, about 1,600–2,000 GWh are lost due to lack of high-voltage line transmission capacity, and some water bypasses the turbines. To avert this, a new aluminium plant was started on 15 December 2006.
History
The decision to build the power station was taken in 1960. On 4 November 1961, geologists reached the area, and an exact location was chosen. Construction started in 1963 and the first turbine went online on 18 December 1978. The plant became fully operational in December 1985. It was partially reconstructed in 1987 and in 1991. The plant was designed by the Leningrad (now Saint Petersburg) branch of the Hydroproject (, ) institute, Lenhydroproject.
Following the collapse of the Soviet Union, the power plant was privatized in 1993, with RAO UES becoming the main shareholder. In April 2003, the Government of Khakassia by the initiative of the governor Alexei Lebed filed a suit to invalidate the deal. In April 2004, the East Siberian Arbitration invalidated the deal; however, it was overruled by the Supreme Arbitration Court.
The plant was closed after an accident on 17 August 2009. Some of the old turbines were subsequently restarted temporarily, but all are being sequentially replaced with updated more efficient equipment. As of Nov. 2014, all 10 generators are operational.
Stability concerns
In 1998, the Russian Emergency Situations Ministry claimed that the "station construction [had] dangerously changed" and that the dam wall might not withstand the repeatedly increasing pressures of the annual spring floods. Since the basement of the dam is weakened, the 30 million tons of water pressure is not divided with 40 % to the shore rocks and 60 % to the dam's own weight as originally designed. Most of the water pressure and probably some of the dam's own weight is driven to the shore rocks since the dam is not constructed to withstand such pressure division.
There were also problems with increasing water filtration through dam concrete. In 1993 the French company "Soletanche Bachy" impregnated dam constructions with resins after which the filtration was reduced and situation improved substantially. In later times the impregnation was repeated by Russian companies.
In 1996 the concrete was repaired on the reservoir side at levels from 344 to 388 meters At the same time, the soil under the dam and supporting it from sides, was impregnated to decrease the water filtration.