Energy Sources

What is Energy?

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5 min readNov 28, 2022


Energy is the ability of a system to perform work but found from various sources and exists in various forms. Therefore, it is hard to find one comprehensive definition of energy. It is the property of an object that can not be created nor destroyed but transferred or converted from one form to another.

Sources of energy renewable and non-renewable sources of energy

Various energy sources may be classified into two types such as renewable and non-renewable sources of energy. Sun is the main source of energy on Earth but it may be found in various other sources such as coal, geothermal, wind, biomass, petrol, nuclear power, etc.

Renewable and Non-renewable Sources of Energy

Energy found from various sources can be classified into two categories:

  • Renewable sources: Solar, geothermal, wind energy, biomass, hydropower, and tidal energy.
  • Non-renewable sources: natural gas, coal, petroleum, nuclear power, and hydrocarbon gas or liquids.

These energy resources differ from each other in the following ways,

  • Renewable resources can be renewed once they are consumed but non-renewable resources cannot be renewed once they are consumed.
  • Energy obtained from renewable resources does not cause any environmental pollution but non-renewable resources cause environmental pollution.
  • Renewable sources are inexhaustible but non-renewable sources are exhaustible.
  • Renewable resources are not affected by human activities but non-renewable resources are affected by human activities.
  • Air, water, and solar energy are the main forms of renewable resources while natural gas, coal, and nuclear power are the main forms of non-renewable resources.

Renewable sources

Renewable sources of energy are derived from natural processes and available plentiful in nature. These sustainable resources of energy can be naturally replenished and are safe for our environment.

The energy obtained from these sources may include:

  • Solar energy
  • Wind energy
  • Geothermal energy
  • Hydropower
  • Ocean energy
  • Biomass energy and Biofuels

Solar energy

Sun is the primary source of energy for our earth and solar energy is a clean and renewable source of energy. It is a sustainable resource because like fossil fuel sunlight doesn’t run out but is affected due to cloudy weather.

Solar technologies can deliver heat, cooling, natural lighting, electricity, and fuels for our daily applications. It converts sunlight into electricity either through photovoltaic panels or through mirrors that concentrate solar radiation.

Solar energy contributes a significant part of the energy required in various counties of the world. The manufacturing and installation costs of solar panels dramatically decreased in the last decade. The solar panel has a high lifespan and fits a variety of shades in your house.

Wind Energy

The wind is used for the production of electricity by converting the kinetic energy of air into electricity. In modern wind turbines, wind rotates the rotor blades that convert kinetic energy into rotational energy. It is transferred by a shaft to the generator for the conversion of electrical energy.

Many parts of the world have strong wind speeds and most wind farms are located in remote areas. It also installed various buildings in the United States.

Geothermal energy

Geothermal energy is an accessible thermal energy obtained from the Earth’s interior. It is a renewable resource extracted from geothermal reservoirs in the form of heat.

Fluids of various temperatures can be used to generate electricity from geothermal energy. The technology for electricity generation from hydrothermal reservoirs is a mature and reliable process and operates in various parts of the world.


Hydropower or hydroelectric power is one of the most useful sources of renewable energy that uses the natural flow of moving water for electricity generation. It provides a significant part of electricity in the world that is needed for a good life.

The large infrastructure used for creating hydropower can affect our ecosystems in adverse ways. Therefore, small-scale hydropower is an environmentally-friendly option and suitable for communities in remote locations.

Ocean energy

Oceans cover most parts of our earth and represent an enormous amount of energy. Therefore, various technologies are used for the production of electricity from the kinetic and thermal energy of seawater. Wave, Tidal, and ocean thermal energy are renewable resources of energy that are still at an early stage of development.

Biomass energy and Biofuels

The plants fix solar energy through the process of photosynthesis for producing biomass. Therefore, bioenergy and biofuel may produce from a variety of organic materials such as charcoal, dung, other manures, and agricultural crops. They pass through various cycles for the production of different forms of energy sources.

Most biomass is used by poorer populations in rural areas to fulfilling their daily energy requirement for heating and lighting. Modern bioenergy systems include dedicated crops or trees, residues from agriculture and forestry, and various organic waste products.

Natural Sources of Energy

Natural sources of energy change from time to time. During the stone age, humans used wood to fulfill their energy requirements. In the iron age, humans used coal as their primary required natural source of energy.

In the modern era, we use fossil fuels such as petroleum, and natural gas to fulfill our daily requirements. Good natural sources of energy should have the following qualities such as optimum heat production, easy transportation, least polluting, and economical use.

The source of energy cannot be pollution-free because it affects our environment in some way. For example, wind energy can be considered pollution-free but the installation may affect the wildlife of our environment. Generally, two types of natural sources of energy are available and used in our daily life. These two sources may include:

  • Conventional sources: Conventional sources of energy are finite resources that will deplete over time. They are exhaustible and cause pollution in our environment. Some of the conventional sources of energy may include coal, petroleum, natural gas, etc.
  • Non-conventional sources: Non-conventional sources of energy are infinite resources that use in the near future after the development of technologies. The maintenance and transport cost of conventional sources is very high and they can be easily stored. Solar, biomass, wind, biogas, tidal, and geothermal all are examples of non-conventional sources of energy. They are pollution-free sources of energy.


Energy Types — Definition, Sources —

Sources of Energy — Vikaspedia

What is renewable energy? | United Nations

4. Energy Sources



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