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Fossil Fuels

  • Writer: Isabella Vegso
    Isabella Vegso
  • Jul 30, 2018
  • 4 min read

Updated: Feb 28, 2021


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Fossil fuels are some of the most prevalent, sought after resources throughout the world. So much in our present society depends on them, from transportation to plastics and to the clothes on our backs. They are also some of the most controversial and debated resources, and their overuse by humans is leading to huge consequences for our planet. Due to the tight grip fossil fuels have on our society and the major controversy surrounding them, it is important to stay informed on what fossil fuels really are; what different kinds are there, how they are formed, how they are extracted, and which are more dangerous to our health and planet.

There are three primary fossil fuels that are utilized most prevalently by our society. Natural gas, oil (sometimes called petroleum), and coal. All are hydrocarbon deposits, however each is unique, with different extraction methods, energy efficiency, and destructive power. First, it is important to understand how fossil fuels are formed;

  1. It all starts with organic matter, such as the vegetation in forests or sea plants and tiny sea animals.

  2. Eventually this organic matter will die, and over time the trees and plants of forests and the plants and animals of the sea will decompose on the forest or sea floor. This decomposing organic matter is called kerogen.

  3. Kerogen, whether on land or on the sea floor, will eventually be covered with layers of sediment that build up overtime, exerting increasing pressure.

  4. The heat and pressure exerted on kerogen builds up over many many years, eventually turning it into fossil fuels.

  5. The varying conditions the premature fossil fuels are exposed to determines which type (natural gas, oil, or coal) will develop. The organic matter from forests will develop into coal, the only sold fossil fuel of the three. Oil and natural gas form from marine plants and animals, with oil forming at a shallower depths and natural gas at lowers depths with higher temperatures.

Due to the varying conditions each fossil fuel forms under, different extraction methods are used for each, with varying consequences.


1. Oil

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Giant dump trucks haul raw oil sands material in Alberta, Canada. Todd Korol/Reuters

SURFACE/ OPEN PIT MINING

  • Carried out when the oil reserve is close to the surface.

  • Entails stripping the surface of the land to access the reserve of bitumen* or crude oil underneath, disrupting large areas of land.

  • Bitumen and crude oil are usually present with large quantities of sand, so therefore the mixture, called tar sand or oil sand, is filtered with hot water to wash out the sand.

  • Whatever is left is refined and processed until it can be sold as a fuel.

  • 79 kg of greenhouse gas emissions are emitted per barrel of oil extracted.


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Steam Assisted Gravity Drainage (SAGD) Illustration

STEAM ASSISTED GRAVITY DRAINAGE

  • Carried out when the oil reserve is far below (at least 100 meters) the Earth’s surface.

  • To separate the tar/oil sands from the sand, high pressure steam is injected into the reserve.

  • The bitumen or crude oil can then flow freely into a well to be pumped to the surface.

  • 60-80% of the reserve is usually recovered, which is then sent to be refined and processed until it can be sold as a fuel.

  • 116 kg of greenhouse gas emissions are emitted per barrel of oil extracted.

*bitumen is very similar to crude oil, however contains more impurities. This causes it to flow slowly like molasses, compared to free flowing crude oil.



2. Natural Gas

Natural gas, mainly composed of methane, can only be recovered if they are trapped by a geologic structure. If not trapped, the gas will migrate up through the permeable rock and seep out into the atmosphere. If trapped, several processes can be used to extract the resource.

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Image courtesy of the National Energy Board


HYDRAULIC FRACTURING (FRACKING)

  • High pressure water, chemicals, or sand are used to split or fracture rock formations*.

  • This opens up cracks in the rock for gas to escape, allowing for higher quantities of natural gas to be extracted.





DRILLING

  • Wells are drilled down into the reserve to extract the natural gas.

  • Can be drilled horizontally as well as vertically to increase the productivity of the well.


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Different drilling methods

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Diagram depicting the process of acidization in a well.

ACIDIZING

  • Process used to increase the productivity of a well.

  • Acidic compounds are inserted into the well to dissolve rock that blocks the flow of natural gas.

These fractures have been linked to micro-earthquakes, which can compromise the structure and stability of buildings and underground pipes.



3. Coal

Coal is the most destructive of the three forms of fossil fuels. There are two ways to mine coal;


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Teck’s Elk Valley metallurgical coal mining operations have come under criticism for their impacts on the environment. Photo: Garth Lenz

SURFACE/ OPEN PIT MINING

  • Very similar process to the extraction of oil open pit mining.

  • The surface of the land is stripped, allowing miners to collect the reserve for transport

DEEP MINING

  • Occurs when the reserve is too deep for open pit mining.

  • A vertical shaft is drilled into the ground, allowing for further horizontal tunnels to be drilled underground to access the coal deposit.



What are the Consequences ?

1. OIL

  • The extraction of oil from the tar/oil sands is a major contributor to the loss of wetlands. Wetlands are an essential ecosystem that provide an important habitat for many plants and wildlife, act as an essential natural filtration system for water, and regulate surface and groundwater flow, preventing floods.

  • Offshore drilling has major negative impacts on marine ecosystems related to the use of seismic waves to locate the oil.

  • Large amounts of water are contaminated to filter the sand from the bitumen or crude oil

  • There is always a risk of an oil spill occurring on land or at sea, jeopardizing the health of many animals and ecosystems.


2. NATURAL GAS

  • Natural gas is often thought to be a more clean form of energy, as it releases far less CO2 emissions than oil and coal.

  • However, because natural gas is mainly composed of methane*, if only 3% of gas is released in the extraction process, all benefits of using natural gas a more environmentally friendly alternative are gone. This commonly occurs during the fracking extraction method.


3. COAL

  • Coal mining is extremely dangerous for the miners, and can lead to lifelong health issues.

  • Mining coal results in the destruction of large amounts of natural ecosystems and habitats, and can contaminate lakes, rivers, and groundwater.

  • The burning of coal releases toxic mercury and other pollutants into the atmosphere and land.

  • Burning coal also releases small amounts of radiation, which builds up over many years of coal fired power plants.

  • About 67% of all energy is lost as waste heat in coal fired power plants.

*Methane is considered to be 30 times more potent than CO2 as a greenhouse gas.

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