The hydroelectric adjective refers to that pertaining to or related to hydroelectricity . This term is linked to the electricity that is obtained through hydraulic energy , which is the type of energy generated by the movement of water.

Hydraulic or water energy, therefore, takes advantage of the kinetic and potential energy of jumps, tides and water currents, forming part of renewable energy since it is not depleted with its use.

The infrastructure that uses hydraulic energy to generate electricity is known as a hydroelectric power plant . Its operation is based on a waterfall that generates two levels of a channel: when the water falls from the upper level to the lower level, it passes through a hydraulic turbine that transmits the energy to a generator in charge of transforming it into electrical energy.

The exploitation of hydraulic energy through a hydroelectric power station can be developed in two different ways. On the one hand, it is possible to divert a river to take advantage of the speed of its flow and generate electricity. Another option is to build a dam and intercept the water stream.

It is possible to distinguish between several types of hydroelectric power station, depending on the point of view of the analysis. If they are studied according to their flow regime, the following four are recognized:

* of flowing water : it is also known as a water edge plant and uses part of the flow of a river to produce electricity. His work is continuous because, because he does not own a reservoir, he does not have the capacity to store water. Its turbines work directly on the water that is available at all times and can have a vertical axis (for rivers with steep slopes) or horizontal (for low slopes);

* Reservoir : this is the most common type of hydroelectric power plant. It uses a reservoir to store water and adjust the flow through the turbine. In this way, provided you have a sufficient reserve, you can produce energy throughout the year. On the other hand, the investment necessary for its creation and maintenance is greater than the alternatives;

* of regulation : it serves to store the water that flows from the river and can supply a consumption of several hours;

* pumping : also called reversible , this type of hydroelectric power station can not only transform the potential energy of electricity into electricity, but also is capable of performing the reverse process, that is, increasing its potential energy through the consumption of electrical energy . This makes it a tool for storing energy, as if it were a battery of colossal dimensions.

On the other hand, four types of hydroelectric power station can be distinguished according to the height of the water fall:

* high pressure : the height of water fall is over 200 meters and used to be associated with Pelton turbines, which are among the most efficient in the field of hydraulic energy;

* medium pressure : using Francis or Kaplan turbines, its drop height ranges between 20 and 200 meters;

* Low pressure : their water differences do not exceed 20 meters and use Kaplan turbines ;

* of very low pressure : they use more recent technologies since Kaplan turbines do not work in cases of slopes less than 4 meters.

Finally, there is the tidal power plant (which uses the ebb and flow of the tides, especially in coastal areas with very different tides), the submerged tidal wave (which uses underwater currents to get energy and dates from 2002) and a class that takes advantage of the movement of the waves (tested for the first time in 1995, in Esococia, after almost two decades of research).