At all tames people thought about how to “put rivers in harness”, how to make the rivers work. In ancient times – in Egypt, China, India water wheels lifted water to the ground.
Water mills used for grinding corn appeared in Urartu (the area of today Armenia) long before wind mills, but they were known already in XIII century b.c.
Water wheels were the basic way of energy production in the end of XVIII century – middle of XIX century. They existed till the beginning of XX century. Hydroturbines with essentially higher degree of efficiency, developed in the second third of the XIX century were being used for a long time for direct drive of machines by the system of wheelwork, rope-drive and belt drive. Today hydroturbines are applied not only for the activation of generators at hydroelectric power stations.
The first Russian industrial hydroelectric power station was put into operation in 1896 year.
It was constructed on the Ochta River in order to supply energy to a local powder mill. In the same time Niagara hydroelectric power stations of constant current started operating.
The operating principle of a hydroelectric power station is common in spite of constructions’ variety: water under pressure from a headrace (a water reservoir in front of a dam) goes to diversion chamber and through water pipe go to the turbines – wheels with 10 m diameter with blades. Water steam beats the blades, turns machine shaft on which the generator is fixed, producing the electrical energy. It is transferred through thick conductors to a step-up transformer and then to a distribution substation and goes to the consumers by electric main under high pressure – to the factories, plants, accommodation units. Hydro generators usually produce electrical energy under 6-16 kV voltage. Their capacity can exceed 650 Mw and the largest ones are located in our country. Modern hydroelectric power station is a complex of hydro technical installations (for water steam concentration and creation water pressure) and energetic equipment with the help of hydro turbines transforming energy of this pressure into mechanical and then into electrical energy (by hydro generators). Turbo generator units are situated in a generator hall – turbine and generator service equipment, automatic control devices.
There are also pump-storage plants. They are constructed in those areas where load in electric systems is not equal during the day.
If consumption of electrical energy is reduced and it is in excess aggregates of the station that are able to operate as water pump, transfer water from reservoir to upper retaining reservoir. If pressure in electric grid rises up to peak an inverse process starts – hydro aggregates, activated by water coming into water supply piping from upper reservoir, produce electrical energy. Capacity of such station is rather high: for example Cornwall hydro-electric power station in the USA it reaches 1620 megawatt. Hydro-electric power stations have many advantages in according with thermoelectric and nuclear power stations. They don’t need any fuel and that’s why they produce cheaper electrical energy. Energetic resources of such stations are great and are continuously renewed. Hydro recourses of rivers are being used due to hydro-electric power stations – constructed dams and reservoirs allow improving water supply of dry areas, making fair way sections longer and decreasing damage of spring floods. However dams of hydro-electric power stations make living environment of fauna worse; ponded rivers, slackening the current begin to effloresce; wide areas of croplands go under water. Without doubt hydroenergetics should be developed without environmental damage.