Hydroelectric plants are some mechanisms used in power plants where turbines are spun or powerful engines and use water power to produce electricity.
The capacity of a hydroelectric plants depends on the amount of water passing per second through the turbines and the drop height of water (in general, it is not a drop in the proper sense, but the flow). But in nature, most often there are large amounts of water (the rivers) or higher heights of fall (in mountainous regions). Consequently, hidroelecrice plants are classified into: -Central with a drop height of up to 50m, called low pressure systems, and central drop of over 50 m, called high-pressure facilities. For this type of plant is no hydraulic turbine generators suitable for driving. The installation of low-pressure turbine shaft is often placed vertically;
It must be properly mounted and the generator. This generator generally has a lower speed than the turbo generator and is endowed with a large diameter rotor and poly apparent. Low pressure hydroelectric find them first addition watercourses. Water is gained through a dam and flows to the turbines. If you do not want to flood large areas of earth dam, drop heights is achieved by only a few meters. Often as not to impede navigation, bulky additional constructions are necessary. The best known high-pressure hydroelectric plants are located at the foot of dams built to create a reservoir. They enclose a narrow valley or a place on the course of water and form lakes, which almost always serve other purposes (water supply, water disposal of high flood hazard). The dam is a construction that stops the course of a river to raise the water level upstream, to create a pool of water, a waterfall hydropower.
The disadvantages are related to dependence on river regime, the existence of water sources, the high value of the investment, carrying out construction work takes more and requires labor-intensive. By building a dam on the water accumulation occurring disturbances, climate, flora, fauna in the surrounding area due to changing rainfall regime disappearing species of plants and animals. Reservoirs prevent the transport of substances that are deposited fertile especially in the mouths of rivers in the delta.
The energy industry has boomed in the second half of the nineteenth century sl, initially based on water energy recovery (the first was a hydroelectric power plant) and mineral fossil fuels (in power plants). Subsequently appeared atomic power, geothermal, termomarine, solar, wind, biomass etc. Currently only three types of plants provide about 99% of total world production: power plants, hydroelectric and nuclear power plants.