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What Are Fossil Fuels & How Do They Work

Feb 16th, 2022

Here at AMLI we talk about renewable energy and sustainability topics quite often, like in our articles on solar power, wind power and hydrogen fuel cells.

However, these topics don’t make much of an impact if we don’t examine what they are attempting to replace. We can’t examine the benefits of green energy if we don't understand the costs of unclean energy, and we certainly can’t advocate for sustainability if we don’t know how much better it is to the status-quo.

So, here’s a brief glimpse into our most-used source of energy on the planet today: fossil fuels. 

Not-so-green energy 101: fossil fuels

How are fossil fuels different?

When we talk about fossil fuels, we usually refer to these three popular and widely used non renewable sources: crude oil, coal and natural gas. They are called fossil fuels because they are made from the remains of living organisms that have been trapped under the heat and pressure of the earth’s crust for millions of years. 

Coal and oil, while both fossil fuels, are made from different materials put through similar processes. And, surprisingly enough, none of them were made from dinosaurs! Dinosaurs first existed around 200 million years ago, which is way, way after fossil fuels started forming around 300 million years ago.

Coal is the byproduct of dead trees and other plant materials that were prevented from decaying, whether through full immersion in mud or under water. Not only were the physical parts of the plants preserved, but the carbon energy within them (as in, energy taken from the sun) remained, too. As time went on and greater pressure and heat were piled on top of these remains, the molecular structure of these organisms broke down into more simple compounds called hydrocarbons. This simplified state makes it easier to combust and react to energy, which is why we use them for fuel.

Oil is formed in a nearly identical process, but oil is made from the remains of ocean-borne organisms that died and sank to the ocean floor. That’s why oil is so often found in the ocean and where there used to be vast amounts of water, like Austin, Texas, for example!

Natural gas is a byproduct of oil formation, so they are usually found hand-in-hand.

The sheer amount of time it takes to transform those remains to combustible fuel means that we will not likely see any new formation of those materials again. At least, not unless we’re around in 300 million years or so. 

How does coal work?

Coal power is the largest source of energy produced and mined here in the United States, and it powers most of the electricity we use day to day. 

The chemical makeup of coal is nearly all solid carbon, which can burn when exposed to heat and oxygen. The carbon dioxide released by that burning process is what creates heat, even when there is no open flame, so coal can continue to burn and combust until either the heat, carbon or oxygen eventually runs out.

To utilize that energy for electricity in a power plant, coal is burned in a large boiler that contains pipes of water running through it. The heat turns the water into steam, and the steam is pumped out into a turbine that spins a shaft which, when connected to a generator, charges the generator and creates electricity. The excess steam is released into the atmosphere, but so is all of the carbon dioxide, sulfur dioxide, nitrogen oxide, mercury and other air pollutants created as a result of coal combustion. Not to mention, there are all the emissions and impacts that come as a result of mining. 

How does oil work?

Crude oil is rarely used in its raw form. Rather, it is refined into a variety of formats such as ethylene gas (which is used to make plastic), gasoline, kerosene, propane, diesel and more, which are then further refined to even more formats. 

Wherever oil fuel is burned, such as in a car engine, the process to turn fuel combustion into energy is similar to that of coal. The high carbon content in the oil (the fuel source) interacts with heat and oxygen, resulting in combustion, which gives off exhaust and heat. The excess heat feeds the fuel further, allowing it to burn as long as there is still fuel and oxygen. 

Energy is created either by harnessing the excess heat to create steam or by harnessing the excess gasses under pressure to create powerful streams of exhaust. Either way, the excess steam or gas is what turns turbines and other mechanics to create electricity. 

The emissions from oil combustion include excess steam, carbon dioxide, nitrogen oxides, methane, sulfur dioxide, mercury and more. The more significant portion of oil-related emissions, however, comes from the drilling, extraction and refining process that take place long before the fuel is even consumed. These are what negatively impact water sources, natural habitats and wildlife.

How does natural gas work?

Natural gas forms along with oil as living organisms break down into hydrocarbons over time, with the lightest forms of hydrocarbons separating from the thicker oil to sit atop the deposit in a gaseous form.

Natural gas deposits have to be tapped in a way that doesn’t release the gas into the atmosphere, so the process requires a fair amount of machinery and resources to keep the reserve under pressure and proper containment. These processes include fracking, which requires massive amounts of water and produces highly toxic discharge. 

When natural gas is ready to be used, it undergoes an identical process to that of coal and oil. The fuel is exposed to heat and oxygen, and the resulting combustion produces heat, which then produces steam, which then goes on to power turbines and generators to produce electricity. 

We often talk about fossil fuels in relation to our energy consumption and usage today, and this is just a tiny glimpse into what it takes to extract these fuels from the Earth and convert it into a usable format. An immense amount of resources are used to obtain the materials, at the direct cost of the surrounding environment and the wildlife that call those places home. And, by the end of it all, there are even more emissions pumped back into the atmosphere as the fuel is converted to yet another form of electricity which, depending on the need, may result in further pollution and emissions. 

When we talk about fossil fuels, we’re not just talking about gasoline cars versus electric cars. We’re talking about a global industry that relies on the destruction of the environment to create energy. That’s why here at AMLI we place such great importance on breaking that cycle one step at a time, whether that’s by using wind turbines to power our Dallas and Houston apartments’ common areas, or by using solar power to generate electricity for some of our Dallas apartments. 

One step at a time, folks! 

Good luck!

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Featured photo courtesy Pixabay/stevepb

Author of Article

Colleen Ford is a South African who now lives in Spokane, Washington. She loves to travel, camp (in warm weather) and bake.

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