Sources of Energy

Everything from which we receive energy is called a source of energy. There are many types of sources of energy.

Non-renewable sources of energy

So far coal, petrol, natural gas and diesel have been major sources of energy. These energy sources are limited in quantity and are likely exhaustible. They cannot be used again and again. Hence they are called non-renewable energy sources.

If we look at our current energy requirement and rapid development in the future, it is expected that our oil and natural gas reserves will end in the next few years. The coal reserves will also not be able to run much. Therefore, we should use our non-renewable sources of energy wisely and avoid misuse of energy as much as possible.

Residual (fossil) fuel

Sources of energy are found in many forms. Residual fuels are the most popular sources, such as coal, wood, petrol, diesel, kerosene, and natural gas. 

Coal is formed thousands of years after the plants are buried in the ground. There is a limited stock of coal found in the coal mines. There will also be a time when all the coal will be used completely and we will have to find other sources of energy. Coal contains chemical energy. When coal burns, this chemical energy is converted into heat. Coal is also used to generate electricity in thermal power planets.

Wood obtained from trees is also used as coal. When wood burns, chemical energy is converted into heat and light. Trees have to be harvested for this source. Therefore, a large number of trees are required to be planted daily to maintain the natural balance.

Other than this, petrol and diesel are used in cars, scooters, trucks, airplanes and other vehicles. Kerosene is used in lamps to obtain light and in stoves for thermal energy. Natural gas is used in gas stoves for cooking. Petrol, diesel, kerosene and natural gas are obtained from petroleum, which is found at very deep depths inside the earth. It is formed as a result of thousands of years of water plants and animals being buried in the ground. They contain chemical energy, which on burning is converted into thermal and light energy. But there is a limited stock of petroleum and once it is exhausted, it will take thousands of years to become fresh petroleum.

Renewable sources of energy

Water, air, sunlight and biomass etc. are called renewable sources of energy. The reason for this is that they can be used again and again. Also, they are available in sufficient quantities, are free and do not pollute the environment. Therefore, efforts are being made to make maximum use of the energy available in them.

1. Food Energy

All living beings get energy from the food they eat. Trees and plants (flora) are the main source of food for all living beings including humans. Trees and plants make their own food by the method of photosynthesis and food is present as chemical energy in plants.

2. Solar Energy

Sun has been providing us with uninterrupted heat and light for billions of years and it is expected that it will continue to provide energy to us for the next billion years. All plants get their energy from the sun and animals get their energy mainly from plants. Therefore, it can be concluded that the sun is the source of energy of animals.

3. Wind Energy

Wind provides energy. Wind power is available for free. It is clean and does not pollute the environment and is reliable. In many areas, where strong winds blow for most of the year, wind cycles are used to draw water from wells and generate electricity. Wind energy is used to rotate wind cycles.

4. Water Energy 

Like flowing air (wind), flowing water is also a source of energy. It is also free and does not pollute the environment. The energy of the running water is used to move large wooden logs and plants from one place to another. The energy of flowing water in hydropower plants (hydro power houses) is used to generate electricity. The flowing water rotates the wheel of a turbine, which helps in generating electricity.

5. Energy from Biomass

Biomass means dead parts of living things and waste material. This includes garbage, industrial waste, crop waste and sewage. We can use biomass as an energy source in two ways:

  • By directly burning dry biomass to generate heat and steam.
  • By creating biogas by decomposition of biomass in the absence of air. Like liquid petroleum gas, this gas can be used for cooking and lighting.

The remaining of the biomass can be used as fertilizer in a biomass plant.