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How does Hydroelectric Power Work

Updated on April 15, 2011


For hydroelectric power station is a set of hydraulic structures located in a certain sequence, coupled with a series of machines suitable for the purpose of obtaining the production of electricity from moving water masses.


The energy produced by hydroelectric plants is to be classified for all purposes as renewable energy because, in theory at least, the water can be reused many times for the same purpose without collapse. The concept of renewability is subject to the constancy of the annual volume of inflows integrals.

Classification and Description


The main classification is the one that is made between:


River plants


The water is diverted into a penstock from them is then fed into the turbines that rotate through the water pressure, all of which it is coupled to an alternator that converts the rotational motion into electrical energy. Impressed with the speed of the water turbine is generated through a height difference, called "jump", which translates into hydrodynamic pressure to the portion where the turbines.


Power Plants


Unlike the "power-of-river" is an artificial lake created by the dam of a gorge with a river dam, which then leave the pipelines, which are enriched by a piezometric well (intervening before the turbine), which dampens and avoid the disruptive effects of water hammer (huge overpressures that are generated when the turbine is stopped by the closed line).


Plants with plants accumulating


Unlike the "Power Plants" have a catchment area downstream including: water that has generated electricity during the day through the turbines may be located downstream from the reservoir upstream of the basin during times of low demand energy (eg at night), by pumping, using for this excess electricity produced by power plants of type "always on" and otherwise accumulates. In other words, the basin of the mountain is "charged" during the night and the water masses found at the mountain can be reused even at peak energy demand.


The latter type of plants are those plants collection. They are realized in ternary groups of machines, namely the turbine, pump and electric machinery, being reversible, if necessary works as a generator or motor. If the plant is equipped exclusively with a basin of a reservoir upstream and downstream (thus without a component of "fluent"), the central power station is called closed-loop or the pumping station. In some plants can also take advantage of the reversibility of certain turbines, such as the Francis turbine, which works as a reverse operation of a pump, reducing the cost of installation and maintenance, compared with an acceptable loss of performance.




The hydroelectric plants have the characteristic of being turned on and off in minutes with the imminent opening of the hydraulic gate, thus giving the possibility to easily cover the sudden surges in demand that may occur. In contrast, most nuclear power plants and have longer working time needed to heat the water and are therefore a type of facilities such as "always on" (or "basic").



A problem related to hydropower is the progressive burial in which inevitably undergo, in time, the reservoirs. To avoid this, they must be dredged periodically.


Environmental problems can be set up by the fact that the dams (dams) block the river sediment (sand and gravel) altering the balance between the sediment and erosive activity in the river downstream (erosion of the bed river, and sometimes "cut of the meandering" for increased speed) to the sea where, for less or no sediment is marked by coastal erosion. Large hydroelectric reservoirs in some cases may also have environmental and socio-economic impacts of different levels or severity of the surroundings (change of scenery and natural habitat destruction, population displacement, loss of agricultural areas, etc..) And the feasibility study must be particularly careful especially regarding the accurate analysis of the geology of the slopes and the "shoulders" on which the dam will settle without leaving any details. The only way you can avoid tragedies like the one in the fall of 1963 devastated the valley of Vajont (deleting the town of Spar and two other centers in the valley with 1970 victims).



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