Fossil fuels can be defined today as the main sources of energy that are non-renewable and are responsible for the massive air, water and land pollution on planet Earth.
Even if we know that the use of fossil fuels is responsible for the massive pollution and the change in the climate conditions taking place on our planet, mankind still uses fossil fuels on a massive scale to generate energy, heat and produce fuels just because they are cheap and the renewable alternative is not developed enough to cover the energy demand of our growing civilization.
Fossil Fuel Definition
Fossil fuels consist of fuels formed by natural processes like anaerobic decomposition of buried dead organisms (marine and terrestrial) that acquired energy from the Sun during their life on the planet due to ancient photosynthesis.
Fossil fuels such as coal, oil and natural gas are finite resources of energy that will someday be depleted, which means that mankind needs to find alternative sources of energy (preferably clean and renewable) to replace the traditional sources of power.
Fossil Fuel Formation
We consider that the today’s fossil fuel reserves have been created hundreds of million of years ago from the dead plants and animals that lived on the planet.
When terrestrial and marine plants and animals have died, all these organisms sank to the bottom of the swamps and oceans where they started to decompose under layers of sand, clay and other minerals.
The three major types of fossil fuels like coal, oil and natural gas were formed from different types of organisms.
Coal
Coal was formed in a period from about 345 million to 2.5 million years ago when the Earth was in the Carboniferous, Permian, Triassic, Jurassic and Cretaceous periods.
At the time, the climate on the planet was mild and wet with plenty of sunlight and rainfall.
The land was covered by swamps that contained an abundance of nutrients, which were ideal for plant growth and animal reproduction.
Due to proper climate conditions, plants and trees grew extremely tall and the entire land was covered by plants and trees.
The ocean also provided very good conditions for a massive development of the marine life.
Coal formation
When plants have died, they sank to the bottom of the swamps and oceans and started to accumulate layer upon layer.
Aided by anaerobic microorganisms in the water, a series of biochemical reactions took place and the dead plants gradually transformed into a dark-brown substance (similar to mud) called peat.
The Peat phase, was the first stage of the plant transformation into coal.
Various forces caused the peat to become buried deep underground, and pressure from sedimentary rock and high temperatures in the underground rock caused the layers of loose peat to be gradually solidified in brown coal.
Turning peat into brown coal (lignite) due to intense pressure and high temperatures in the underground rock was the second stage of coal formation.
In the third stage of coal formation (bituminous coal or soft coal formation), brown coal was continuously subjected to intense pressure and high temperatures, which made water to be evaporated and carbon content increased.
In the fourth stage of coal formation (anthracite or hard coal formation), anthracite was formed due to combined pressure and high temperature.
Anthracite contains almost no water and very high concentrations of carbon, which makes it to burn with a short flame that produces little smoke.
Oil
Crude oil or petroleum was often formed in ocean beds from marine organisms such as plant materials (seaweeds), phytoplankton and practically any living (organic) organisms that lived and died there.
After dying, all these marine organisms sank to the bottom of the ocean forming a sea bed that started to be compacted under sediments such as sand and mud.
Over a very long period of time and due to the numerous layers of sediments that covered the layer of dead marine organisms, they got buried deep underground where due to high pressure and temperature, they turned into crude oil.
Oil is extracted from the reservoir using wells, and once recovered from the underground is transported through pipelines, or using ships, railway or trucks.
Once arrived at the refinery, crude oil undergoes several refining processes to be turned into petroleum products such as gasoline, diesel fuel, jet fuel, asphalt, etc.
Natural gas
Natural gas or methane (CH4) was formed millions of years ago when dead marine organisms sunk to the bottom of the ocean and in time were buried under deposits of sedimentary rock.
Due to high pressure and temperature in the underground rock the marine organisms have been converted to gas over millions of years.
Natural gas reserves are located today under seas and oceans, but also in the underground rock on the land.
Natural gas reserves are categorized today as dry or wet.
Dry gas is essentially a gas containing mostly methane, while dry gas contains methane and other compounds such as ethane and butane.
Conventional natural gas is extracted through drilling wells, while the unconventional forms of natural gas such as shale gas, tight gas. sour gas and coalbed methane (CBM) require specific extraction techniques.
Natural gas is frequently associated with oil reserves
Natural gas can also be found in oil reservoirs (associated gas) and is extracted along with oil.
Once extracted, natural gas is sent through pipelines to processing plants to separate the various hydrocarbons and extraction fluids from the pure natural gas in order to produce ‘pipeline quality’ dry natural gas.
After processing, natural gas is sent through pipelines (feeders) to distribution centers or is stored in underground reservoirs for later use.
For shipping in large tankers across the planet, natural gas is liquefied and becomes liquefied natural gas (LNG).
Fossil Fuel Applications
Coal is a fossil fuel with a long history on our planet because it was used to run furnaces and melt metal ore since ancient times.
The use of fossil fuels, coal at first and followed by petroleum much closer to our time petroleum, were the main engines powering the Industrial Revolution.
Natural gas was no longer wasted and considered an unwanted byproduct of the oil or coal extraction, started to be used as fuel in gas lights.
The invention of the engine with internal combustion used by cars and trucks increased the demand for fossil fuels (gasoline and diesel fuel).
The other forms of transportation such as railways, aviation and shipping also used fossil fuels (oil).
Tar is obtained in the petroleum extraction and is used in construction (roofing tiles), and to build roads.
Olefins and aromatics produced in oil refineries are used in the petrochemical industry.
However, the most important use of fossil fuels is in heat and electricity production.
More than 63% of the energy produced today in United States is generated by fossil fuels like coal and natural gas.
Oil is mostly used in the transportation sector.
Environmental Effects of Fossil Fuels
Today, natural gas is used for industrial processes, to heat homes and buildings, for cooking and also in the transportation sector.
In terms of electricity generation, natural gas accounts for about 35% in the energy mix of the U.S.
Coal is also used for heat and electricity generation, but before being used by coal-fired power plants as fuel, needs to be turned into coal dust, which is more explosive than the coal rock itself.
Fossil fuels still represent the main source of energy for mankind
In terms of electricity generation, coal accounts for about 27% in the energy mix of the U.S.
Fuels obtained from oil are used to power the transportation sector (cars, trucks, ships, aircraft, trains, etc.)
All fossil fuels used today (coal, oil and natural gas) are the remains of the organisms that lived on our planet millions of years ago, which means that they are mainly composed of carbon and hydrogen.
When we burn fossil fuels for heat and energy generation, a large number of greenhouse gases (water vapor and carbon dioxide) along with particulate matter and other harmful gases (nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO) and volatile organic compounds (VOC) are released into the atmosphere.
The very large volume of greenhouse gases released into the atmosphere every year due to the fact that we burn fossil fuels for energy has increased the greenhouse effect on our planet, which leads to global warming and climate change.
Final conclusion
Fossil fuels were and continue to be the main sources of power on planet Earth, but due to fact that the planet is warming up and could trigger major climate changes that would affect all life on the planet, we need to understand that we slowly need to increase the generation capacity for renewable energy.
Only by replacing the dirty fossil fuels with renewable energy sources such as solar, wind, hydro, biomass, geothermal, tidal, wave and hydrogen, we can stop the climate change effects on our planet and we can create a clean and healthy environment for the future generation.
