Ust-Ilimsk Hydroelectric Power Station is the third step of the Angarsk cascade of hydroelectric power stations, after Irkutsk and Bratsk Hydroelectric Power Stations. The power site is located below the mouth of the Ilim River - the right inflow of the Angara. Its construction started in 1963. In 1974, filling of Ust-Ilim water basin started; in 1980 the station was accepted for industrial operation.
Ust-Ilimsk Hydroelectric Power Station is a high pressure reservoired hydroelectric power station. The structure of the basic constructions of the hydro-unit includes: concrete solid dam of 1475 m in length and 105 m in height, consisting of a stationary dam of 396 m in length, overflow dam of 242 m in length, and blind parts of the dam (in the stream canal and bank) of 837 in length, and also left-bank earth-and rockfill dams of 1710 m in length and 28 m in height, and the right-bank earth (sand) dam of 538 m in length and 47 m in height. The building of the hydroelectric power station of 440 m in length is located at the right bank directly behind the stationary part of the dam. 16 units are installed in it with combined-flow turbines and generators of umbrella-type.
The design capacity of Ust-Ilimsk HPS equals 4320 MW. The installed capacity is 3840 MW. Average multiyear production of electric energy amounts to 21.7 billion kWh/year. The guaranteed production is 20.7 billion kWh/year. Annual average use of the installed capacity is 5050 hours.
In 1981 Ust-Ilimsk Hydroelectric Power Station produced the first 100 billion kWh.; in 1986 it produced 200 billion kWh; 300 billion kWh were produced in 1991; 400 billion kWh were produced 1995; 500 billion kWh were produced in 2000. 530 billion kWh of electric energy were produced as of March 18, 2002.
The structure of Ust-Ilimsk Hydroelectric Power Station includes Management; Laboratory of Hydraulic Engineering Constructions (LHEC); Service of Means of Dispatching and Technological Management (SMDTM); Electric and Technical Laboratory (ETL); Operational Workshop.
The staff of Ust-Ilimsk Hydroelectric Power Station amounts to 194 people.
On October 1, 2005, at 20:52, 600 billion kWh were produced. The station celebrated its 30th anniversary in December 2004.