Different Types of Energy Sources

The scientific definition of energy is that “Energy is an indirectly observed physical quantity which is the ability of body or a system to do work.”  On a logical point of view, we can understand energy as something which enables us to do work. If we have energy then work can be done. Energy is conserved in systems, meaning that it can neither be created nor destroyed but is inter-convertible into its different forms. Some of the many forms of energy are:

  1. Kinetic energy.
  2. Potential energy.
  3. Gravitational energy.
  4. Nuclear energy.
  5. Chemical energy.
  6. Heat energy.
  7. Electrical energy.
  8. Electromagnetic energy.
  9. Sound energy.
  10.  Solar energy.

Different Sources of Energy

Photosynthesis (Image source: sxc.hu)

We live in the age of technology and machines which need various forms of energy to make them work. The general household contraptions require electricity to make them work (know who invented electricity). Vehicles on the other hand need kinetic energy to move it. The resources from which the required energy is harvested are known as “Sources of Energy”. In nature, all biological systems harvest their energy from the sun, directly or indirectly. Plants utilize the solar energy from the sun and produce carbohydrates through the process of photosynthesis. Herbivorous animals get their energy by eating these plants and carnivorous animals get their energy by eating these animals and the food chain continues.


These sources of energy may not always give energy in the form we require but whatever form is harvested from the source is converted by the prescribed mechanisms and converted into useful energy. For example, the engine of a car runs by the combustion of fuel i.e., the chemical energy released from the combustion of the fuel causes the air in the engine cylinder to expand which in turn moves a piston causing a shaft to rotate and consequently producing torque to rotate the tyres of the vehicle to move it. In the case of electricity produced from nuclear reactors, chain reactions of radioactive uranium releases enormous amounts of heat which heats up water present around it giving rise to a lot steam. This steam is used to rotate turbines which produce electrical energy. So, in order to produce electrical energy, we utilize the nuclear energy from the uranium making it an indirect source of electrical energy.


Types of Energy Sources

There are two types of energy sources, Renewable and Non-Renewable sources. Renewable energy sources are sources that can be replenished or which are available naturally in excess. Non-Renewable energy sources are limited in their availability.


Renewable energy sources are more ‘Environment-Friendly’ as they do not cause any natural imbalances. Acquisition and usage of Non-Renewable energy sources causes disruption and disturbs the balance of environment. List of Energy sources according to their types are


Non-Renewable Energy sources:

  • Coal
  • Nuclear Energy
  • Oil
  • Natural Gas


Renewable Energy sources are:

  • Air (Wind Energy)
  • Water (Hydro-Electric Energy)
  • Sun (Solar Energy)
  • Biomass (Alternative fuels)
  • Hydrogen
  • Inner Earth Layers (Geothermal Energy)


Globally, the more preferred and large scale energy harvesting is through the non-renewable sources. It is the general convention as it is easier to harvest on a large scale. Renewable resources are also catching on in usage as new technologies are emerging to harvest energy from them. The non-renewable resource storage is getting used up rapidly and so the requirement of renewable resources based energy is quite critical these days.


Fossil Fuels (Coal, Petroleum and Natural Gas)

(Image source: sxc.hu)

Fossil Fuels, as the name suggests are formed by fossils which are compressed by the pressure of the earth’s crust under the duration of thousands of years and so they cannot be replaced as soon as they have been consumed. When coal is burnt, it releases a lot of energy which is used to convert water to steam and the steam is made to run turbines to produce electricity. Petroleum finds it place in the combustion chambers of an internal combustion engine to power various machines. Also the usage of such fossil fuels also promotes emission of harmful greenhouse gases, increasing the volume of global warming.

Nuclear Energy

Nuclear energy is harvested from Uranium-238 which is extracted from the sparsely present Uranium ores. The Uranium extracted from these ores is used in nuclear reactors, the heat from which produces steam which runs turbines to produce electricity. Uranium is mined only 19 countries and comprises only 6% contribution of energy in the world. However, a downside of nuclear energy is radioactive waste. The mistreatment of radioactive waste leads to devastating consequences which include cancer. Even damage to the reaction chambers by either natural or man made disasters causes radioactive contamination in the surrounding area which will last for a very long period. One such event was seen after the Japanese Tsunami, 2012.


Renewable Resources

Extraction of energy from renewable resources requires the extra effort, an extra touch to technology since the renewable resources, when compared to the non-renewable resources, are more unpredictable in their outcomes and also give an outcome on a lower scale.

Solar Panel

Solar Panels (Image source: sxc.hu)

Light energy from the sun can be harvested by solar panels which capture the photons and convert it to electrical energy. But a very minor amount of electricity is produced from large amounts of sunlight, which is not available throughout the day. So, solar energy is not capable of providing large units of current. Another drawback is the installation of the solar panels which needs direct sunlight causing an inconvenience of space.Mostly solar panels are used to run heaters. Modern day advancements in technology are promoting a wider range usage of solar energy to promote a greener environment.


Hydroelectric energy is harvested from the movement of water in streams, rivers or waves from seas and oceans. Hydroelectric power plants are also installed at dams to utilize the force of the water bodies. Specially designed turbines are placed under water to harvest the kinetic energy from the moving water. Hydroelectric energy can power larger units of electricity and is used in collaboration with energy produced from coal to reduce fossil fuel usage.

Wind Energy

Windmills (Image source: sxc.hu)

Windenergy is harvested by using wind currents to turn the fans of windmills in turn converted to electrical energy. Wind energy is quite efficient and one windmill can provide electricity to a small home. Windmills are usually used by farmers in the outskirts where there is more place to install a windmill. Windmills also require a climate which is quite windy regularly.


Biomass is used to produce alternative or bio fuels from which energy can be extracted. Biomass is a collective term for biological waste such as garbage, animal excretes and biological by products of industries. Unlike the rest of the renewable  energy resources biomass is not restricted by climatic conditions which makes it the front runner of the renewable resources. Improvements in technology have seen the use of biomass fuels to power engines and generators.