Fossil fuels.
Extraction of oil

Thermal Power Plant Cercs. Catalonia

Treatment of fossil fuels

Thermal energy and combustion.
Effects of thermodynamics

What Are Fossil Fuels?

Fossil fuels are a non-renewable energy source. This resource comes from decomposed animals and plants. It is a natural resource that takes millions of years to regenerate.

What are fossil fuels?

Fossil fuels are currently the most widely used energy source in the world. The main utility is to generate electricity. They are also used to generate mechanical energy (automobiles, heat engines, etc.).

The carbon content in these minerals is high. In consequence, the combustion generates greenhouse gases such as carbon dioxide. The greenhouse effect is one of the main causes of climate change. Not letting heat escape into space accentuates the global warming of the planet.

The main uses of fossil fuels are electricity generation and transportation.

What are fossil fuels?

Fossil fuels are combustible materials formed from fossilized organic remains. They are a series of substances and gases formed from the remains of animals and plants. This process is generated in certain layers of the soil for millions of years.

They are all made up of hydrocarbons. Hydrocarbons are molecules made of carbon and hydrogen atoms

Animal and plant remains undergo a process of partial decomposition of organic matter.

These are primary energy sources since they can be obtained directly without transformation.

These materials have a high calorific value. For this reason, they are used in thermoelectric power plants or in devices that operate using heat sources.

This multi-million-year process turns fossil fuels into a non- renewable energy source. They are consumed much faster than they are regenerated.

This energy source is considered as non-renewable energy because it is not possible to regenerate it on a human scale.

What is the origin of fossil fuels?

The origin of fossil fuels are plants and animals. They are formed through a process of partial decomposition of organic matter and plant remains. This transformation process lasts millions of years. It is a consequence of the high pressure and temperature that various layers of sediment exert on organic matter.

They have originated naturally by a fossilization process in environmental anoxia (lack of oxygen). Organic matter has not been degraded by microorganisms, but remains in the form of more complex organic molecules. These molecules can be solids, liquids, and gases.

The energy of these molecules is the one released in using them as fuel.

This millions-year-old process is what turns fossil fuels into a non-renewable energy source. The speed with which they are consumed is much greater than the speed with which they regenerate.

Why are fossil fuels important?

Fossil fuels have a high calorific value that makes them a very valuable source of thermal energy. It is important both for its ease of extraction and for its calorific value.

Fossil energy production is used to generate electricity and to generate mechanical energy.

Fossil fuels caused great economic and demographic growth linked to the 19th century Industrial Revolution. Today they are fundamental to our economy.

Fossil fuels supplied about 80 percent of the energy consumed in the United States in the last years.

Effects of fossil fuels on the environment

The combustion of this type of fuel generates greenhouse gas emissions such as carbon dioxide, carbon monoxide, and other gases. These gases have contributed and still contribute to generate and enhance the greenhouse effect, acid rain, air, soil, and water pollution.


Fossil fuel extraction implies some risks to the environment.

Ecological damage


Biological systems are incredibly complex. Those systems can be the victims of serious ecological consequences because of this source of energy.


Wild mammals and birds respond to these disturbances with behaviors that many studies have shown can become common. The damages include:

  • The interruption of the communication of songbirds.

  • It affects the breeding and nesting stations.

  • The alteration of the dynamics between predators and prey.

Spills of petroleum


Onshore oil operations require drilling fluids that are injected into the well to lubricate the bit. These fluids are supposed to be captured in parallel wells for disposal. However very often they spill and splash the surroundings.

Whet accumulated they generate long-term impacts on the environment and chronic effects on the health of workers. It includes the potential risk of cancer.


Offshore oil spills affect marine mammals through direct contact, inhalation, and ingestion of oil.

The problem becomes worse when it is done using hydraulic fracturing techniques or fracking

Changes in the landscape


Activities associated with drilling for oil and gas radically impact the landscape. Padding and road construction requires the use of heavy equipment such as bulldozers, road levelers, and trucks.


The consequences are:

  1. Elimination of vegetation

  2. Increased erosion (which could lead to landslides and floods)

  3. Soil disturbances (even with the appearance of earthquakes in the case of Fracking)

  4. Fragmentation of habitats, etc.

Air and water pollution

Open wells, ponds, and ponds may contain sewage, organic chemicals, petroleum hydrocarbons, tensile actives, and other substances, which compromise water safety.


Explosions from pipes and wells can contaminate aquifers. Gas well development may even require methane releases, air pollutants, and a myriad of toxic gases in the atmosphere.


Methane, the main component of natural gas, is up to 84 times more damaging to the atmosphere than carbon dioxide emissions. Methane traps heat more effectively and intensifies global warming.


The combustion of this type of fuel generates emissions of gases such as carbon dioxide, carbon monoxide, and other gases. These gases have contributed and still contribute to generate and enhance the greenhouse effect, acid rain, air, soil, and water pollution.

Types of fossil fuels

Three types of fossil fuels are distinguished:

1.- Oil (in liquid or liquefied gas form)

Petroleum is a mineral oil contained in large pockets to the upper layers of the earth's crust. It has a liquid structure, but it can also be presented as liquefied gas.

Oil undergoes a transformation process in a refinery. Once refined, it provides a large number of products used as an energy source. Petroleum products include gasoline, diesel, fuel, etc.

The sectors that benefit the most from oil are automotive and thermal engines. They can also be used as raw materials for the petrochemical industry.

The energy efficiency of oil is approximately 25.7%.

What is the difference between crude oil, petroleum products, and petroleum?

Crude oil is a mixture of hydrocarbons. Petroleum products are produced from the processing of crude oil at petroleum refineries. Petroleum is a broad category that includes both crude oil and petroleum products.

The terms oil and petroleum are sometimes used in the same way.

2.- Carbon (solid)

The coal or mineral coal is a sedimentary rock of black color, very rich in carbon. It contains variable amounts of other elements, mainly hydrogen, sulfur, oxygen, and nitrogen.

What are fossil fuels?

Most of this non- renewable energy source was formed during the Carboniferous period (from 359 to 299 million years ago).

The energy efficiency of oil is approximately 26.8%.

One way to make coal cleaner is carbon capture and storage (CCS). CCS system works capturing CO2 before it is emitted. Afterward, the gas is then turned into a fluid and injected deep underground.

The availability include of CCS include coal and gas natural.

3.- Gas natural

Natural gas is the cleanest fossil energy in terms of waste and atmospheric emissions.

The calorific value of natural gas varies greatly depending on its composition. The highest values ​​are between 8,500 and 10,200 kilocalories per cubic meter of gas.

It is the most efficient fuel for obtaining electricity in thermal power plants, with a total efficiency of 50.7%. If natural gas is used directly without transforming it into electricity, the efficiency rises to 91.2%.

Its storage is cheaper and easier than coal and oil derivatives.



Published: May 18, 2016
Last review: June 16, 2020