Hydroelectric energy is the most widely used form of renewable source of energy. Unlike the fossil fuels, it does not produce any waste product or release carbon dioxide into the atmosphere. Hydroelectric energy accounts for about 19 percent of the world electricity.
Water has been long used to produce energy. Hydroelectric energy is generated by the rotation of water turbines at a very high speed by the fast flowing water that has been released from dams in mountainous regions. In this whole process, the energy of running water is first converted into mechanical energy of the turbines which is then converted into electric energy. Places with steep mountains and high rainfalls are ideal for producing hydroelectric energy. The hydroelectric energy plants require large dams to be built across rivers which are very expensive. But after that, it has a very low operating cost. Also since the flow of water can be controlled, hydroelectric energy can be obtained whenever required. Using hydroelectric energy plants also has several disadvantages. Building of dams can cause the blockage of fish passage to the ocean or to the spawning ground. Hydroelectric energy plants can also have an effect on the quality of water by reducing the dissolved oxygen content in the water.
The use of water in order to produce hydroelectric energy is an attractive substitute to the non renewable fossil fuels. But the technology has still some work to do in overcoming obstacles related to building costs, space requirements, displacement of people and the environmental impacts.