Fossil fuels are made from the remains of plants and animals that died a long time ago. Over millions of years, these remains turned into carbon-rich deposits that we now dig up and burn for energy. But they won't last forever, and presently, they supply about 80% of the world's energy. 

Such fuels involve coal, petroleum, natural gas, oil shale, bitumen, heavy oils, etc. This guide will help you learn more about fossil fuels, their types, uses, pros and cons, conservation, and more.

Fossil fuels refer to the natural energy resources formed from the remains of once-living organisms over millions of years. These remains decayed down the line and were converted into petroleum, natural gas, and coal due to the tremendous heat and pressure within the earth's crust. 

Fossil fuels are mainly composed of carbon and hydrogen; their energy is released through combustion (burning). Since they take a long time to replenish, they are also called non-renewable energy sources.

A few million years ago, algae and plants lived in shallow seas. When they died, they settled at the bottom of the sea and mixed with other sediments, getting buried. Later, under high pressure and high temperature, this organic material was transformed into what is considered ‘fossil fuels’ today. 

Fossil fuels are classified into three main categories that include:

1. Coal

Coal, also known as black diamond, coal is a sedimentary rock formed from ancient plant remains, primarily composed of carbon and extracted through mining. When burned for electricity and industrial purposes, coal releases carbon dioxide and pollutants, significantly impacting global warming and air quality.

2. Petroleum

Petroleum, or crude oil, is a liquid found underground, consisting of hydrocarbons used to produce fuels like gasoline and diesel through refining. While it serves as a major energy source for transportation and industry, the combustion of petroleum releases greenhouse gases and pollutants. Petroleum is also known as ‘liquid gold’.

3. Natural Gas

Natural gas, mainly methane, is extracted from underground reservoirs alongside petroleum. It is a clean-burning fuel for heating, electricity, and industry, producing fewer greenhouse gas emissions than coal and oil. However, methane leakage can contribute to climate change as a potent greenhouse gas.

Below are the fossil fuels used in various fields:

1. Uses of Coal

• Coal was used in the past to produce steam in the railway engines.

• Coal is used to cook food.

• Coal is used to produce electricity in thermal plants

• Coal is used in industrial sectors as fuel.

2. Uses of Petroleum

• Petroleum comes in the form of petrol, which runs internal combustion engines.

• Petroleum is used for roofing, road pavements, and as a water repellent.

• Petroleum is used in the manufacture of detergents, plastics, fibres, polyethene, etc.

3. Uses of Natural Gas

• Compressed Natural Gas (CNG) is used to generate power.

• Natural gas is used as fuel in vehicles.

• Natural gas can be used in households for cooking.

• Natural gas is a primary ingredient in producing chemicals and fertilisers.

Here are the noteworthy benefits of fossil fuels:

• Fossil fuels can produce a significant quantity of electricity in one specific area.

• Fossil fuels are found very easily and they are quite cost-effective.

• Transportation of fossil fuels like oil and gas can be carried out easily through pipelines.

• Fossil fuels remain abundant despite their finite nature.

• The usage of fossil fuels has become safer over the years.

Mentioned below are the major drawbacks of fossil fuels:

• They produce carbon dioxide when burned, which is a principal greenhouse gas and the main source of pollution. This has resulted in global warming.
• They are a non-renewable resource, i.e., once they have been used, they cannot be replaced.
• The combustion of fossil fuels makes the surroundings toxic and keeps altering the environment in unpredictable and undesirable ways.
• The harvesting of fossil fuels also causes fatal diseases. For example, coal miners often suffer from Black Lung Disease. Natural gas drillers are constantly exposed to chemicals and silica that are dangerous to their health.

Fossil fuels are exhaustible due to their finite quantity and extremely slow rate of formation. These substances formed hundreds of millions of years ago and cannot be replenished within a human lifetime. The growing energy demand worldwide has been extracting and exhausting these resources faster than their natural regeneration.

Moreover, the act of extraction itself is potentially harmful to the environment, leading to habitat destruction, water pollution, and greenhouse gas emissions. For truly sustainable energy use, there is an increasing need to switch to renewable energy sources in as much abundance as would not deplete them over time.

Coal and petroleum are known as fossil fuels as they originate from the remains of ancient plants and marine organisms that once existed on the earth millions of years ago. As time passed, these organic materials were buried deep inside the soil and transformed into coal and petroleum owing to the immense heat and pressure of the earth’s crust. 

The term ‘fossil’ signifies the organic origin of these fuel minerals and the lengthy geological processes involved in their formation.

Since fossil fuels cannot reproduce themselves after being consumed, we need to save them by using other alternative energy sources. The following are the ways of saving fossil fuels:

• Opt for public transportation or carpooling when travelling.

• Only use air conditioners or heaters when necessary.

• Consider utilising alternative energy sources such as solar, tidal, wind, and so on. 

• Turn off the car engine at traffic lights to conserve fuel.

• Replace ordinary incandescent bulbs with energy-saving CFL bulbs.

• Take the stairs instead of using elevators, especially when going down.

• Use pressure cookers for cooking to save LPG or kerosene.

• Switch off lights, fans, television, and other electrical appliances when not in use.

• Encourage the use of biogas as a domestic fuel.

• Avoid deforestation and plant more trees to ensure a proper oxygen balance in the atmosphere.

• Recycle and reuse old products and thus save energy. 

• Properly insulate homes as it can reduce the amount of energy needed for heating and cooling.

Fossil fuels, as they naturally occur (coal, petroleum, natural gas), cannot be artificially created in a laboratory by the same geological and biological processes that occur over millions of years underground. However, there is burgeoning research into synthetic fuels aiming for replicas of the performance of fossil fuels but through alternative processes such as biomass conversion or chemical synthesis. 

These synthetic fuels can be produced in laboratory conditions or specialised industrial premises but with totally different production methods compared to naturally extracted fossil fuels.

Examples of fossil fuels include the following:

• Coal: Including varieties like lignite, bituminous, and anthracite.

• Petroleum: Also known as crude oil, extracted from underground reservoirs.

• Natural Gas: Primarily methane, which is found in natural gas fields and associated with oil deposits.

• Peat: Partly decayed plant material, a precursor to coal.

• Sub-Bituminous Coal: Intermediate grade of coal containing 35–45% carbon. 

• Oil Shale: Sedimentary rock comprising kerogen can be transformed into synthetic crude oil.

• Tar Sands (Oil Sands): A mixture of sand, clay, water, and bitumen, a heavy oil that can be processed into synthetic crude oil.

• Methane Hydrates: Ice-like deposits of methane and water found in Arctic regions and beneath ocean sediments.

• Lignite: Lowest grade of coal, often used in power plants.

• Bitumen: Thick, sticky form of petroleum, often found in tar sands.

   

Fossil fuels originated from decaying plants and animals millions of years ago and have been transformed into crude oil, coal, natural gas, or heavy oils. Today, humans extract fossil fuels through coal mining and the drilling of oil and gas wells both on land and offshore. 

They are the natural sources of energy and have expansive applications in the industrial as well as domestic sectors.