Science: Sources of Energy: Importance and Various Forms of Energy (For CBSE, ICSE, IAS, NET, NRA 2022)

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  • Energy plays an important role in your life.
  • Energy is important in everyone՚s life, whether you notice it or not.
  • Without sufficient energy people face difficulties doing their day to day work.
  • All forms of energy including solar energy, light energy, mechanical energy, nuclear energy, and the energy of our body are important to Us.


  • Energy is defined as the ability to do work. We require energy for all types of activities including the activities within our body, with our body or with other bodies.
  • e. g. An engine uses energy of its fuel to move a car along. A battery stores the energy needed to switch on the radio or tape recorder.

Importance of Energy

  • Energy plays a very important role in our lives, providing comfort, increasing productivity and allowing us to live the way we want to Without energy even our body would be unable to perform basic functions like respiratory, circulatory, or digestive functions.
  • Plants would also be unable to complete the process of converting Carbon dioxide, water and minerals into food without the light from the Sun.
  • the electrical energy has become so important that almost in all walks of life electricity is required.
  • For example, all electrical appliances in our homes and at our workplace require electricity. All the industries and factories run on electricity.

Various Forms of Energy

Solar Energy

Solar power harvests the energy of the sun through using collector panels to create conditions that can then be turned into a kind of power.

Wind Energy

Wind power is becoming more and more common. The new innovations that are allowing wind farms to appear are making them a more common sight.

Geothermal Energy

Geothermal energy is the energy that is produced from beneath the earth. It is clean, sustainable and environment friendly.

Hydrogen Energy

Hydrogen is available with water (H2O) and is most common element available on earth. Water contains two-thirds of hydrogen and can be found in combination with other elements.

Tidal Energy

Tidal energy uses rise and fall of tides to convert kinetic energy of incoming and outgoing tides into electrical energy. The generation of energy through tidal power is mostly prevalent in coastal areas.

Non- Renewable Energy Source

They cannot be regenerated in a short period of time or used again and again. Hence, they are called non-renewable sources of energy. we get most of our energy from non-renewable energy sources which include fossil fuels such as coal, crude oil and natural gas.

Renewable Energy Source

They can be generated or used again and again. Hence, they are called renewable sources of energy. E. g. Solar energy, wind energy, tidal energy etc.

Fossil Fuels – Conventional Source of Energy

Conventional Source of Energy
  • Fossil fuels, such as coal, oil and natural gas, are important non-renewable sources of energy.
  • These are the primary sources for generating electrical energy in the world today.
  • Over 85 % of our energy demands are met by the combustion of fossil fuels.
  • Carbon is the main constituent of these fossil fuels. Fossil fuels are excellent sources of energy for our transportation needs.


  • Coal is made of decomposed plant matter in conditions of high temperature and pressure, though it takes a relatively shorter amount of time to form.
  • There are different types of coal such as peat, lignite, sub-bituminous and bituminous.
  • Peat which is merely a mass of dead and decomposing plant matter. Peat has been used as fuel in the past, as an alternative to wood.
  • Lignite, a brownish rock that contains recognizable plant matter and has a relatively low calorific value. Lignite is basically the halfway point from peat.
  • Sub-bituminous which is a shade of dull black with very little visible plant matter. This type of coal has a less than ideal calorific value.

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