Natural resource of Class 9


It is the capacity to do work. All of us require energy to meet our daily needs. And it is the most important requirement of all humans’ civilizations. There are different source of energy such as  

Source of Energy

The most important source of energy are

  • coal

  • petroleum

  •  natural gas

  •  hydro power

  •  Solar

  • wind and nuclear power.

The various energy resources are classified in two categories :

  • Non-renewable or conventional energy resources
  • Renewable or non-conventional energy resources.

Non-renewable or conventional energy resources. Fossil fuels such as coal and petroleum are present in limited quantity and cannot be renewed. They have been in use since a long time and have become a convention. Such resources are called non­renewable or conventional energy resources.

Renewable or non-conventional energy resources. Solar radiation, hydel power, wind power, biomass and nuclear power are renewable or non-conventional energy. These are pollution free sources of energy and can be recycled or renewed in nature.

Our country has developed a capability for generating energy from different sources. The total power generation capacity of our country has increased from 1,400 MW (megawatt) in the year 1947 to 97,800 MW till March 2000.

 Different sources of power generation in India

Sources                                Electricity production (in MW)

Thermal power (solar energy)      70,200

Hydel power                               23,800

Nuclear power                             2,700

Wind power                                 1,150

Biomass power                             256

The solar energy is the biggest source of non-conventional source of energy followed by hydel power. Different devices have been developed over the years in our country to tap the non-conventional sources.

Non-conventional Energy Sources

Some of the non-conventional energy sources are:

Hydel power   It is the next biggest source of energy after thermal power.

To generate hydel power, the flow of water is checked by building a dam. The collected dam water is allowed to flow through the tunnels with high pressure to move turbines and generators. Thus, the potential energy of water is converted into electrical energy by the moving turbines and generators. 

Hydel power plants of our country are generating 23,800 MW of energy.

Solar energy …Sun is an inexhaustible and pollution free source of energy. It is the biggest source of non-conventional source of energy. We receive abundant sunshine for about 250 to 300 useful days in a year.

 The solar energy is being trapped and converted into thermal and electrical energy. The     conversion of energy is achieved mainly through photovoltaic conversion. The solar energy is used in devices such as solar cookers, solar heaters, solar dryers and solar cells. In our country solar energy is used for community lighting, rural telecommunication system, pumping of water for small irrigation and drinking purposes. and in operation of railway signals. Solar energy has proved a boon to several remote villages of India.

Wind energy

The use of wind energy is another important development. Wind power is converted into mechanical and electrical energy.Speed of winds is very high in the coastal areas, therefore, such places are good zones for harnessing wind energy. Wind turbines have been installed in coastal regions of our country. Kutch and Okha in Gujarat, Purl in Orissa and Tuticorin in Tamilnadu have wind turbines.

These are used in the generation of energy, presently, more than 1,000 MW electricity is being generated in India by wind.Tidal energy. Tidal power of the sea is also being used to generate mechanical and electrical energy in our country.Ocean thermal energy and ocean wave energy are going to be the next non-conventional sources of energy. The ocean thermal energy conversion (OTEC) and wave energy production are same useful plans of our government to meet the energy requirement of the country.

New Technologies for Producing Energy

Scientists and technologists working in national laboratories and industries are involved to develop new non-conventional sources/devices of power generation.

These include :

  • Hydrogen energy. Liquid hydrogen is being used as primary fuel for the hydrogen based fuel cells and power plants. Hydrogen energy can be generated for residential, industrial and transport purposes.
  • Geothermal energy. The heat of hot springs (natural geysers) is called geothermal energy. It is being utilised for power generation and direct heat applications.
  •  Ocean energy. The energy of ocean contained in temperatures gradient (i.e. temperature differences between the surface and deeper layers), waves and tides can be used to generate electricity. Technologies are in process to harness the oceanic energy to meet our requirement.


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