Non - Conventional Sources of Energy

 Non - Conventional Sources of Energy

• The sources of energy which do not belong to fossil fuels and nuclear fuels are called alternative source of energy.
• e.g Hydroelectric energy , Wind energy , Solar energy , Biomass energy ,Tidal energy , Sea - wave energy , Ocean thermal energy  , and Geothermal energy .

 Alternative sources of energy are used due to two reasons :

1.  Fossil fuels and nuclear fuels in the earth are limited which are not produced again  when exhausted .
2.  There occur no pollution due to alternative sources of energy.

HYDROELECTRIC ENERGY :

• Electric energy obtained  by using flowing water is called hydro- electric energy .

• A power plant that produces hydro- electric energy is called hydro-power plant (or hydroelectric power plant). 

 A hydro-power plant produces electricity as follows.

• Rain falling on the high ground in hilly areas flows down into  rivers.

• A high-rise dam is built to stop the flowing river water .Due to this, a large lake or reservoir  builds up behind the dam.

• The water of  reservoir consist potential energy due to its high level from ground.

• The  sliding gates at half the height of dam are opened  to escape stored water. This water is taken through pipe to the turbine installed at the bottom of the dam . the potential energy of falling water is changed into kinetic energy.

• When water fall on turbine then it exert high pressure on turbine.  Thus turbine rotate very fast .

• The turbine is connected to generator through its shaft .When the turbine rotates, its shaft also rotates and drives the generator.

• Thus the generator produces electricity.

• When the hydroelectric generator works and produces electricity, water flows out of the dam continuously and the level of water in the reservoir falls slowly.The reservoir is filled up again by the rain water .

• Since water in the dam reservoir is refilled each time by  rains, therefore, hydroelectric power is a renewable source of energy.

• At present, almost one-fourth of the total electric power is contributed by hydroelectricity in our country.

 Advantages of Generating Hydroelectricity:

• The generation of electricity from flowing water does not produce any environmental pollution.

• Flowing water is a renewable source of electric energy which will never get exhausted.

• The construction of dams on rivers helps in controlling floods, and in irrigation.

Disadvantages of Generating Hydroelectricity :

• Large areas of agricultural land, human settlements (or villages) get submerged in the water of reservoir formed by the dam. Due to this many plants and trees are destroyed, animals get killed and many people are rendered homeless.