Hydropower is the electric power produced in a hydroelectric power station from a current, vertical or horizontal, of a river. In other words, it is electricity (electrical energy) obtained from hydraulic energy (mechanical energy of water in movement of rivers, lakes and marshes).
The difference between hydroelectric and hydraulic energy is that hydraulic energy can be used to generate electrical energy but also to obtain energy of another type, for example, mechanical energy. While hydropower refers only to the use of hydropower to obtain electric power or electricity.
The technical potential for hydropower growth worldwide is 71% Europe, 75% North America, 79% South America, 95% Africa, 95% Middle East, 82% Asia Pacific. The political realities of the new reservoirs in Western countries, the economic limitations in the third world and the lack of a transmission system in undeveloped areas, result in the possibility of developing 25% of the remaining potential before 2050, with most in the Asia Pacific Area. Some countries are highly developed and have very little room for growth, Switzerland 12% and Mexico 20%.
Methods of harnessing hydroelectric energy
For the use of water to obtain hydroelectric energy, there are different methods. Next, we explain the main ones.
Conventional hydroelectric power (dams)
Most of the hydropower comes from the potential energy of the dammed water that drives a water turbine and a generator in a hydroelectric power plant. The power extracted from the water depends on the volume and the height difference between the source and the water outlet. This height difference is called head. A large pipe (the "gate") delivers water from the tank to the turbine.
This method produces electricity to supply the high peak demands by moving the water between the tanks at different elevations. In times of low electrical demand, the capacity for generating excess electric power is used to pump water to the upper reservoir. When demand increases, water is released into the lower reservoir through a turbine that generates electricity again.
Pumping storage schemes currently provide the most important commercial means of large-scale network energy storage and improve the daily capacity factor of the generation system. Pumping storage is not a source of energy, and appears as a negative number in the lists.
Run-of-the-river hydropower stations are those with little or no reservoir capacity, so only water from the upstream is available for generation at that time, and any oversupply must go unused.
A constant supply of water from a lake or an existing reservoir upstream is a significant advantage when choosing sites for the river current. In the United States, the run of hydroelectric power from the river could potentially provide 60,000 megawatts (80,000,000 hp) (approximately 13.7% of total use in 2011 if continuously available).
Tide & ndash; Tidal energy
This type of renewable energy is a tidal power station that makes use of the daily rise and fall of ocean water due to the tides; such sources are highly predictable, and if conditions allow the construction of reservoirs, they can also be dispatched to generate energy during periods of high demand.
The less common types of hydroelectric schemes use the kinetic energy of water or undamped sources such as water wheels that can not be reached. The energy of the tides is viable in a relatively small number of places around the world. In Britain, there are eight sites that could be developed, which have the potential to generate 20% of the electricity used in 2012.
Hydroelectric power stations
The hydroelectric power plants use the mechanical energy of the water dammed by the intake work that acts as a barrier. Water circulates through a pipeline where the potential energy is transformed into kinetic energy. The force of the water rotates the set of turbines, generators and alternators, generating the electric power of alternating current. In this case, the energy extracted from the water depends on the flow, the difference in height from which the water is extracted and the type, height and size of the turbines.
We will find hydraulic power stations in areas where there are water flows (rivers and lakes) and important level differences.