Hydroelectric energy uses the energy of water, taking advantage of its unevenness and movement to generate mechanical energy that is then transformed into electrical energy.
The production of electricity in hydroelectric plants uses the flow and difference in level available in a given river section. The productive potential in hydroelectric energy is thus directly related to the orography of the territory, which generates usable falls, and to the available surface water resources, which in turn determine the volumes that can be turbocharged.
Hydroelectric power stations are generally located along the riverbeds, and may be associated with dams with regularization capacity, usually medium and large, or with dams without regularization capacity, which take advantage of the energy of river flows in a natural regime (exploitation the water stream).
Small hydroelectric plants can have different configurations, with the aim of optimizing the available turbine flow rate and available head at each location. The figure on the side shows the schematic composition of one of the types of small hydroelectric development in headwaters, where the greatest orographic differences are found.
These uses are generally exploited by run-of-river, whenever possible with partial regularization through a sluice in the hydraulic circuit to concentrate the energy produced during off-peak hours, and integrate small collection works, hydraulic circuits on free surface and under pressure. , plants equipped with turbines, generally of the Francis or Pelton type, and the necessary interconnections with the national electricity grid.
The technology of hydroelectric plants is well developed, enabling the generation of electricity in a safe, cheap and non-polluting way, representing an excellent alternative, both in terms of the environment (no emission of greenhouse gases) and economic aspects (decrease in fossil fuel imports).
Advantages of Hydroelectric energy
Hydroelectric energy, when compared to other energy sources, has a set of advantages linked, in particular, to its cost-effectiveness. The main advantage of hydroelectric plants is that they use water, a renewable natural resource, to produce energy.
Despite the numerous environmental impacts caused by hydroelectric plants, they emit a lower volume of atmospheric pollutants when compared to other energy supply units, such as thermoelectric plants. The operating costs of hydroelectric plants are considered low. These plants also admit other uses, especially for their reservoirs, such as for the development of tourism and leisure activities.
Disadvantages of Hydroelectric energy
Hydroelectric plants are often touted as a force for producing clean energy. However, these units are responsible for a set of environmental impacts, which cause a profound transformation of the natural environment. The list below presents the main disadvantages of hydropower plants:
• Alteration of the population's ways of life, often forcing the exodus to another region due to the inundation of the territory.
• Suppression of native vegetation through the flooding of large areas of forest for the construction of dams.
• Emission of gases that intensify global warming, such as carbon dioxide and methane, produced through the decomposition of organic matter.
• Accentuation of the silting up of rivers due to the intense modification of the natural flow of river water and its hydrological processes.
• Extinction of species, especially aquatic, the most affected by the change in the flow of water in rivers.
• Disequilibrium of ecosystems through the transformation of environmental dynamics and the alteration of natural resources, such as soil, air and water.