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Sources of Energy


     Man is surrounded by an ocean of energy but he has been able to tap only a fraction of it. The most colossal dynamo of all energy is the sun, an unimaginable vast powerhouse which affects everything on earth.

Characteristics of Sources of Energy

     It should do a large amount of work per unit mass or volume - it means that the output energy must be more than the input energy. It should have high calorific value.

Energy Resources

     It includes fuels which are most commonly used such as wood, coal and petroleum. These fossil fuels are non-renewable sources of energy. Therefore we need to conserve them.

Thermal Power Plant (Thermal Energy)

     Large amount of fossil fuels are burnt everyday in power stations to heat up water, to produce steam which further runs the turbines to generate electricity.

Hydro-electric Power Plant (Hydro-electric Energy)

     The energy of flowing water is utilised to produce electricity on a large scale at hydroelectric power plants.

Technological Improvements for Using Conventional Sources of Energy

     Given the large live-stock population in India, we can use this fuel as a steady source. These fuels are obtained from plant and animal produces, so it is called bio-mass.

Sources and Principle of Biogas Plants

     Biogas is a clean and efficient fuel. It is a mixture of methane (CH4), carbon dioxide (CO2), hydrogen (H2) and hydrogen sulphide (H2S).

Wind Energy

     Moving air is called wind and it possesses Kinetic energy. In the earlier days, it was utilized by man in winnowing to remove husk from grains, in propelling sail boats in rivers and seas for transport purposes.

Alternative or Non-conventional Sources of Energy

     Due to the ever increasing demand for energy, we need to develop specific devices that can harness energy from non-conventional sources like - solar energy, energy from the sea, geothermal energy and nuclear energy.

Advantages of Using Solar Cells

     They have no moving parts and hence require little maintenance and work quite satisfactorily without any focusing device.

Energy from the Sea (Oceans)

     Tides are caused due the gravitational pull of the moon on the water in oceans and seas. The enormous movement of water between the high tides and low tides provides a very large source of energy in the coastal areas of the world.

Wave Energy or Sea-wave Energy

     Energy from the oceans is also available in the form of oceanic waves or sea-waves. Due to the blowing of wind on the surface of ocean, very fast sea-waves (or water waves) move on its surface.

Ocean Thermal Energy

     The water at the surface of an ocean gets heated by the heat of the sun and attains a higher temperature than the colder water at deeper levels in the ocean.

Energy from Earth's Interiors

     'Geo' means earth and 'thermal' means heat. Thus geothermal energy is that heat energy obtained from hot rocks present inside the earth.

Nuclear Energy

     The process of splitting of a heavy nucleus into a number of light nuclei with the liberation of tremendous amount of energy and two or three neutrons is called nuclear fission.

Environmental Consequences

     The energy source that we actually choose depends on various factors like the cost, the ease with which it is available, the efficiency of the technology available and the environmental damage that will be caused by using that source.


     A thermal power plant utilizes thermal energy of fuels such as coal, oil, natural gas or radioactive substances for the generation of electric power.


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