The IPS/UPS is a wide area synchronous transmission grid of some CIS countries with a common mode of operation and centralized supervisory control. It has an installed generation capacity of 300 gigawatts, and produces 1,200 terawatt-hours (TWh) per year for its 280 million customers. The system spans eight time zones.
The creation of the unified power system started in 1956 by interconnecting the power systems of Center and Middle Volga. By 1978, the unified power system included all of the Soviet Union, excluding Central Asia. In addition, in 1979–1993 the power systems of Poland, German Democratic Republic, Czechoslovakia, Hungary, Romania and Bulgaria, now part of the synchronous grid of Continental Europe (ENTSO-E), operated synchronously with the Unified Power System of USSR. Central Asian countries (excluding Turkmenistan) were included to the integrated system in 2001. In 2009, Uzbekistan disconnected from the system resulting also in the disconnection of Tajikistan.
The Russian portion of the interconnection is known as Unified power system of Russia (UPS) (Russian: Единая энергетическая система России) and includes six regional transmission operators: ECO Center, ECO South, ECO North-West, ECO Middle Volga, ECO Urals and ECO Siberia. ECO East operates in isolation from UPS of Russia.
UPS of Russia came into existence as a result of Russian Federation Decision #526 dated 11 July 2001 "On the Restructuring of the Russian Federation United Energy System". Up until 1 July 2008 RAO UES operated UPS. It is currently being operated by the Federal Grid Company (FGC UES) of Russia.