Ob is the longest river in Russia. Its length is 5410 kilometers. It originates in Altay and flows in the north into the Kara Sea. There's a reservoir in the south part of the riverbed, called the Ob Sea. It was founded in the last century while the construction of a dam of Novosibirsk Hydroelectric Power Plant. The Power Plant makes a part of the Integrated Energy System of Siberia and is a regulating source of electricity. For 50 years Novosibirsk hydroplant has produced 93 billion kilowatt-hours of energy and economized around 28 million tonnes of coal, and that is equal to 9 thousand railway carriages with this expensive fuel. Andrei Ivanov told about how it works in this film.