Hydropower is derived from the course of rivers and lakes through the creation of dams and penstocks.
There are different types of center: in the central jump will exploit large drop heights available in the mountain regions.
In-river plants are used instead masses of river water that exceed small drops; to do this, however, the river must have a considerable flow and a constant engine speed. The water of a lake or a reservoir is conveyed downstream forced through pipes, thus transforming its potential energy into pressure and kinetic energy due to the distributor and to the turbine. The mechanical energy is then transformed through the electric generator, thanks to the electromagnetic induction phenomenon, into electric energy. To allow to store energy and have it available at the time of peak demand, they have been put to generation of hydroelectric power plants and pumping point. In hydroelectric pumping plants, the water is pumped into the tanks upstream exploiting the energy produced and not required during the night so that in the daytime when the demand for electrical energy is higher, you may have additional masses of water from which produce energy.
These systems allow you to store energy in times of availability for use in times of need. Hydropower is a clean energy source (there are no emissions), integrative, (not to be confused with alternative), and renewable. The production of hydroelectric energy can also be done through the exploitation of wave, tidal and ocean currents. In this case it is called tidal energy.