What are fossil fuels?

We explain what fossil fuels are, how they form and examples. Uses, importance and the environmental impact they generate.

1. What are fossil fuels?

Fossil fuels, such as oil , coal and natural gas, are those that  come from the natural decomposition of organic matter  (plants, microorganisms, bacteria and algae), after a transformation process that can last more than 600 million of years.

They are called non-renewable energies because they  are limited natural resources  because they require an extensive period of time and specific conditions to be formed. There is no other way to generate them. Despite this, they are the main source of energy worldwide because of their high calorific value compared to other sources such as wind energy or solar energy.

2. Formation of fossil fuels

The organic matter accumulated over millions of years at the bottom of lakes and seas undergoes various alterations due to the increase in  soil pressure and temperature . It is then transformed into different types of sedimentary rock or fossils that contain concentrated heat. Thus, substances such as oil, coal or natural gas originate that, through excavation processes, can be extracted from the depths of the soil . Then, through treatments, they can release that concentrated energy to become fuels.

3. Examples of fossil fuels

Four types of fossil fuels are distinguished:

• Coal. It is a dark black sedimentary rock, rich in carbon and other chemical elements such as hydrogen, sulfur, oxygen and nitrogen. The extraction of this mineral can be done in two ways: through open pit mining (when coal is less than 60 meters deep) or through underground mining.
  Between the nineteenth and mid-twentieth century trains, ships and industrial machinery operated thanks to the energy of this fuel. Today, despite having been surpassed by oil in terms of its energy capacity, coal is used for the production of plastics and oils, among other uses.
• Petroleum. It is an oily liquid composed of carbon and hydrogen (a conjunction called “hydrocarbon”) that is extracted from a well, between 600 and 5000 meters deep. To obtain it, drilling towers are installed that can be located on the earth’s surface or on platforms at sea. From oil you can produce plastic, printing inks, rubber for the manufacture of tires, gasoline, among the main ones in a long list.
• Natural gas. It is a mixture of hydrocarbons in the gaseous state , mostly methane and, to a lesser extent, nitrogen, carbon dioxide , butane, among others. It is extracted with drilling towers and, by means of pipes designed to transport large-scale gases, it is directed to the power plants for later transport by sea. Natural gas has no smell and is colorless, that is, we cannot perceive it with the senses. Therefore, a product with an odor is added to detect it in cases of leakage.
• Petroleum liquid gas. It is mainly composed of butane and propane, gases that are compressed into liquids, and are obtained as a byproduct of the process of refining petroleum or natural gas. It is mainly used as an alternative fuel for cars that run on gasoline. These are adapted to work with both gasoline and liquefied petroleum gas. Despite generating less power than gasoline, its differential advantages are the economic price and the lower emission of carbon dioxide.

4. Uses and importance of fossil fuels

Fossil fuels were discovered thousands of years ago . However, it was from the  Industrial Revolution  (in the mid-eighteenth century) when they began to be used on a large scale in transport and machinery.

Today they  are the main source of energy for societies  because they release a large heat load, they can be transported easily and their cost of production is cheaper  compared to other alternative sources. They are used to generate  electrical energy  and, mainly,  mechanical energy  (for machinery, cars, airplanes, etc.).

They have multiple uses, such as:

• Residential. Derivatives of oil and natural gas can be used in equipment such as water heater, kitchen, carafe, electric generator, among others.
• Commercial. They can be used similarly to residential but on a larger scale. For example, in central heating systems.
• Farming They are used for equipment that generates hot air in greenhouses, for irrigation pumps, the machinery that works the land, among the main ones.
• Industrial. Natural gas is used in production machinery, such as in ovens, dryers or boilers.
• Transport.  Petroleum and natural gas derivatives are used as fuel for motor vehicles, to facilitate cleaner combustion of engines or as a coolant.

5. Environmental impact

The process of extracting fossil fuels is harmful to the environment . The drilling work operates 24 hours a day, which disrupts the habitat order almost completely. The following problems may occur:

• Ecological damage. The increase in vehicle traffic, the deployment of work machinery and the activity of the workers harm the local fauna . There have been changes in the relationship between predators and prey, as well as the interruption of communication between songbirds during nesting and breeding.
• Spills The liquids used during the excavation process are discarded in parallel pits for later treatment. However, sometimes they partially spill and their long-term impact can cause damage to the land and affect the health  of the inhabitants. Oil spills offshore affect marine animals through direct contact, inhalation and fluid intake.
• Changes in the landscape. The construction of roads to move the necessary machinery to the excavation zone causes the partial or total elimination of vegetation and increases soil erosion . This wear, which is carried out in an accelerated way, causes damage that impacts local agriculture : it causes floods and generates loss of the upper layers of sleep rich in nutrients, among the main problems.
• Water and air pollution. Parallel trenches that are used to discharge the waste are open wells which may contain water sewage, chemicals, petroleum hydrocarbons and other substances that compromise the safety of the drinking water . Occasionally explosions of pipes and wells occur, despite having been drilled properly. This causes pollution of aquifers and air , by the release of methane gas and carbon dioxide that in large quantities are harmful to the atmosphere and to the local environment.