Coal and Petroleum

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What are Fossil Fuels?

Fossil fuels are non-renewable energy sources, they are only present in a limited quantity. Fossil fuels are exhaustible natural resources. If we don’t use them judiciously they will not last for a longer time. 

Even though they are formed by natural processes, they take millions of years for the same. Remains of terrestrial marine flora and fauna which decayed centuries ago get converted into fossil fuels, they are buried in layers due to the huge amounts of pressure and heat. Since carbon is the main element in fossil fuels (coal & petroleum), they cause pollution.    


Black colored rock-like fuel in which carbon content may vary between 70-90 percent is known as ‘coal’. It is formed as a result of the decomposition of vegetation under heat and pressure. The process of formation of coal is known as carbonisation. The time period taken for ‘carbonisation’ is called carboniferous age. Coal is used for generating electricity. Coal is extracted from earth through the process of underground mining or surface mining. Coal is burnt to produce energy. It is widely used as a domestic fuel for making food in rural areas. Harmful smoke is released as coal is burnt. Peat, lignite, bituminous, and anthracite are the four stages of coal formation. Coal consists of carbon, hydrogen and oxygen.

Types of Coal


It is lowest in rank in terms of carbon content. Lignite is the youngest type of coal deposit. It is soft in nature and its color ranges from black to shades of brown. It is also referred to as brown coal. It is not used widely since other types of coal are way better in terms of handling and storage stability. Lignite helps in generating electricity and synthetic natural gas. It is also used for producing fertilizer products like anhydrous ammonia and ammonium sulfate.       


As lignite gets subjected to continuous high temperature and pressure for millions of years, the oxygen and hydrogen content comes down considerably and carbon content increases up to 75 %. The type of coal produces less greenhouse gas emissions. Sub-bituminous coal is also utilized for generating electricity and finds its applications in other industrial processes as well. 


It is blacker and harder than sub-bituminous coal. Bituminous coal is made up of a tar-like substance called bitumen. Hence, it got its name ‘bituminous’. It has 85 percent of carbon content. It is used extensively in the coal industry. Bituminous coal is utilized for energy generation and for heating purposes. It is used for manufacturing cement and has other industrial uses as well.


Anthracite is considered as the most superior form of coal. It has the highest carbon content (over 85 percent). Anthracite which burns as a smokeless fuel in furnaces is harder than bituminous.


Petroleum is basically a black colored liquid fossil fuel. It contains a variety of hydrocarbons. Being a very useful energy source, it is highly viscous. The petroleum which will be extracted from oil wells will not be in direct usable form. The impure substance is referred to as ‘crude oil’.

Crude oil is refined through fractional distillation, different hydrocarbons get separated and form different fractions. Some of the fractions are petrol, kerosene, paraffin and diesel. Petrol is widely used as fuel in vehicles. Fractions obtained by refining crude oil are used for transportation, and also in manufacturing of several products including plastics, tires, and synthetic materials (Example: Polyester). In short, after refining, crude oil becomes a dependable and portable source of energy.

Advantages of Petroleum

  • High-density fuel.
  • Easy to extract.
  • It can be stored, shipped, and piped over long distances as well.
  • Variety of uses, stable energy resource.

However, burning coal and petroleum is harmful to the environment.

Differences between Coal and Petroleum

  • While coal is found in solid state, petroleum is found in liquid state.
  • Since it’s hard and bulky, transporting coal is expensive. Meanwhile, the transportation cost of liquid petroleum is low.  
  • Smoke, ash and other harmful gasses are emitted while burning coal, on the other hand, emissions are comparatively lesser while burning petroleum.
  • Extraction cost of coal is high. Extraction cost of petroleum is low.
  • While coal is cheap in price, petroleum is an expensive product.


Coal and petroleum are widely used across the globe, it is important to think about their conservation. The process of using a resource in a more careful manner, so that it will last for a longer period of time is known as ‘conservation’. We should preserve valuable coal and petroleum by switching to alternate/renewable energy sources such as hydel power, wind energy, tidal energy etc.

The need of the hour is environmentally friendly options ushering sustainable development. It will help us in dealing with the future energy crisis!

Check Your Knowledge

Answer) Fossil fuels are non-renewable energy sources, they are only present in a limited quantity.  

Answer) Black colored rock-like fuel in which carbon content may vary between 70-90 percent is known as ‘coal’.

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