Hydroelectricity is the production of electricity from the falling water.  Hydroelectricity power plant is the renewable energy source and it does not generate any harmful chemicals and gases during the process of electricity generation. This electricity accounts for approximately 20% of the world electricity and it comprises total 88% of the renewable energy sources.

Types of Hydroelectricity Processes & How Hydroelectricity Works
The different types of hydroelectricity come from the water stored in dams; these dams convert the potential energy present in the water to the electricity with the support of generators. The amount of energy which can be pulled out from water depends upon the working of Head (difference of height between the source and water flow). Penstock is a type of pipe which is used to increase the pressure of the water in hydraulic turbines. This is the traditional method of producing electricity. Another type of hydroelectricity production process is pumped storage hydroelectricity plant is used to balance the load of water. In this method water is stored in the form of water. The water is pumped from lower elevation to higher elevation. The water stored in this way is used when the demand of electricity increases. The energy generation efficiency of this plant is not sufficient. However this plant can generate high revenues in the time of peak demand for electricity. This energy system is the very large scale grid energy system which can provide good capacity for water storage.

Advantages of Hydroelectricity Power Plants
First let us look at the advantages of hydroelectricity power plants. The cost of operating hydroelectricity power plants is invulnerable to the fluctuations in fuel prices. Hydroelectric power plants can survive up to 10 to 15 years without incurring any maintenance cost. Hydroelectric dams are environment friendly because they do not burn fossil fuels to generate energy. The water reservoirs are another source of increase the beauty of the land which can attract tourists. The water storage can be helpful in supporting water games. Hydroelectric dams can store the rain water hence narrowing the chance of floods.

Disadvantages of Hydroelectricity Power Plants
The major disadvantages of hydroelectric power plant are that they face the failure hazard even supported with good infrastructure. The silt from the rivers settles down at the surface of dam hence it can slender the storage of water.  Hydroelectricity power plants require very large geographical area for its working forests and cultivated land is converted to store rain water in dams. In order to make these power plants safe and harmless they should be constructed far away from human population, so that the failure and destruction of the dams does not harm humans in the form of floods.

Hydroelectric Power Plants and Its Effects

If we compare the effects of hydroelectric power plants with other sources of energy, it ranks high in the list. The pollutant gases like sulfur dioxide, carbon monoxide and nitrate oxide which pollute the air are not at all part of this energy source. This reason can be attributed to the working of hydroelectric power plants without using fossil fuels. Hydroelectricity power plants are safer than nuclear power plants because they do not generate nuclear radiations during the process. Hydroelectric power plants are more efficient and predictable as compared to wind power plants. Hydro electric power plants store water in huge quantities which can be used to supply electricity in times of immense demand. The hydroelectric power plants are built by planning for the project for many years. Widespread analysis regarding the site study is conducted and then these plants are deployed. China, Canada and Brazil have the highest number of dams in the world. The china alone generates 17.11% hydroelectricity of total hydroelectricity production in the world.