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What are fossil fuels?

What are fossil fuels, how do we use them in our everyday lives and what problems has this caused? Let's explore.
An oil rig stands in the middle of the sea
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What are fossil fuels?

Fossil fuels are materials that were formed as a result of natural processes over millions of years. Examples of fossil fuels include natural gas, petroleum and coal.

When these fuels are burned they produce large amounts of heat energy (relative to their size) as well as carbon dioxide and water.

Fossil fuels have been instrumental in providing the energy required to support industrialisation from the late 18th century onwards and they continue to play a significant role in our lives, providing 85% of the world’s primary energy sources. They can be processed into petrochemicals, currently supplying up to 96% of our organic chemicals.

Here are some examples of everyday things that use fossil fuels or petrochemicals:


Nitrogen is one of the largest macro-nutrients needed for plant growth. Natural gas is used to produce ammonia and urea, two components of nitrogen-based fertilizers in huge quantities.

Such fertilizers improve crop yields, essential to feed the growing population.


60% of the energy used to produce aluminium comes from coal. Aluminium is used widely in aeroplanes, cars and trains to make them light and energy efficient and also in homes because it is easy to extrude and shape.


Hydrogen is used as both a liquid and gas by a number of industries to produce chemicals, food and electronics. Natural gas is a common source of hydrogen, which is produced by a process known as steam reforming.

The hydrogen can then be captured and stored.


The main ingredient of the common pain reliever aspirin is acetylsalicylic acid. This is made via a chemical reaction involving the following petrochemicals: cumene, phenol and benzene.

Many capsules and coatings are also polymer-based. No prizes for guessing where the topical ointment Vaseline or ‘petroleum jelly’ originates from!


Synthetic plastics come from crude oil, natural gas or coal. These raw materials are refined or transformed into different products including monomers which are then chemically bonded into chains called polymers.

The final step in producing plastics is compounding, where blends of materials are mixed by melting, made into pellets and then moulded into the final product.

These plastics can be used to make products such as:

  • Trainers: Most pairs of trainers are made of plastics, from the soles to the uppers and the eyelets and even the laces. Plastic has enabled manufacturers to make shoes that are lighter, more comfortable and enable us to run faster.
  • Contact lenses: Although originally invented using glass, in 1953 chemist Otto Wichterle invented a new type of plastic known as hydrogel with water-absorbing properties that made it perfect for contact lens wearers. Polymers make up nearly 100 percent of soft contact lenses and are worn by millions of people all over the world.
  • Clothing: Many of our clothes contain plastics such as polyester, nylon, polyamide and acrylic. They make our sportswear quick-drying and stretchy, our shirts easy to iron and our fleeces light and warm.

Chewing gum

Once upon a time chewing gums used natural latex from trees. Nowadays long polymer molecules with elastic properties called elastomers are combined with fillers, emulsifiers and softeners to create the gum that can be found everywhere, including many places it shouldn’t, like pavements!

Detergents, such as shampoo

Liquified petroleum gas or LPG is used in dry shampoo. Many shampoos contain sodium lauryl sulfate or SLS which is a surfactant that breaks oils down into tiny globules that can be easily washed away and can be synthetically derived from petroleum.

Hand sanitizers and soap

Hand sanitizers use petroleum-derived ethanol, propanol and isopropanol to destroy pathogens, including COVID-19 when soap and water may not be available.

When soap is available, it’s likely that it contains petroleum as part of its formulation.

The problem with fossil fuels

As well as the problem of fossil fuels running out and becoming more and more difficult to obtain, burning them releases 35 billion tonnes of carbon dioxide per year into the atmosphere contributing to global warming and environmental pollution.

Many of the petrochemical-derived products listed above need a lot of energy (from more fossil fuels) to make and can be difficult to recycle, often ending up lost to the economy as valueless litter.

Is there a different way to make the things we need? Yes, it’s called the bioeconomy.

© University of York/BioYorkshire
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