Coal: The Nonrenewable Energy Resource of the Past

Small pieces of coal, some being held by two hands

Three hundred million years ago, giant plants died in swamps before the dinosaurs roamed the earth. Water filled the globe atop the dead plants, bringing sediment and animals with it. Dirt and rocks covered the remains of the plants, while buried, the dead plants would be subjected to heat and pressure, reducing the oxygen content of the plant matter which left behind rich hydrocarbon deposits creating coal.  


Coal has been a reliable source of power, contributing to industrialization and economic development. Here, we will dive into this resource – examining what it is, if it is renewable or nonrenewable, the different types, and how it is converted into energy. Additionally, we’ll explore the emphasis on adapting renewable energy resources, focusing on the specifics of solar energy and the financial benefits. 

What is Coal?

Coal is a combustible black or brownish-black sedimentary rock, mainly composed of carbon dioxide along with other elements like hydrogen, sulfur, oxygen, and nitrogen. It is a fossil fuel often used for heat, electricity generation, and industrial processes but also contributes to pollution and greenhouse gas emissions.

Small pieces of coal, some being held by two hands

Is Coal a Renewable or Nonrenewable Resource?

Coal is considered a nonrenewable resource because it is finite and takes millions of years to form. As mentioned above, it is formed from the remains of plants that lived and died millions of years ago. The rate of coal formation is much slower than the rate at which it is being consumed. Production of this resource cannot not keep up with our consumption. Once coal is extracted and burned, it cannot be quickly replenished or generated. This is in contrast to renewable energy sources like solar, wind, and hydropower, which are replenished relatively quickly and can be sustained long term without depleting reserves.

4 Different Types of Coal

There are different types and amounts of carbon dioxide in the composition of coal; therefore, they each result in different amounts of heat energy production. Coal is categorized into four main types and these types are formed based on the amount of pressure and heat acted on the coal’s previous form, changing over time.


  1. Anthracite contains between 86%-97% carbon dioxide and typically has the highest heating value. This type of coal makes up less than 1% of coal mining in the United States of America. Anthracite is mostly used in the metal industry.
  2. Bituminous contains 45%-86% carbon dioxide and is around 300 million years old. This is the most abundant type of coal in the United States of America, making up about 45% of total coal production in the country in 2021. Bituminous coal is used to generate electricity and is an important material for use in iron and steel industries.
  3. Subbituminous contains about 35%-45% carbon dioxide. Most of this coal is about 100 million years old and it has a lower heating value than bituminous coal. In 2021, about 46% of the United States of Americas’ total coal production was subbituminous.
  4. Lignite coal contains 25%-35% carbon dioxide and has the lowest energy content out of the four coal types. It has high moisture content and falls apart easily, giving it a low heating value. This is the youngest type of coal and was responsible for 8% of US coal production in 2021.
Construction dump truck getting filled with rock, dirt, and debris

How Coal Becomes Electricity

Coal is relatively close to the earth’s surface, and it is one of the most abundant fossil fuels throughout the world. Harnessing energy from coal happens through a process called combustion, to produce heat. Here is how coal is converted into energy, we use to power our lives and homes:


  1. Mining: Coal is extracted through surface and underground mining. Miners harvest coal deposits. Soil and rock layers are removed to access coal seams. 
  2. Transportation: The extracted coal is then transported for processing. 
  3. Preparation: Once it arrives at a power plant, the coal is cleaned of impurities and crushed to make the burning process simpler. 
  4. Combustion: In a power plant, coal is burned in a furnace or boiler. Burning coal generates heat, which heat is used to generate steam by boiling water. Steam then powers turbines which are connected to generators and in turn generate electricity. The burning of coal is also known as thermal or steam coal. 
  5. Electricity Generation: The rotating turbines generate electricity as they turn. This electricity is then distributed through power grids for your household consumption. 


Coal has been a reliable source of energy for years, but its combustion comes with environmental challenges. In the conversion process, it produces large amounts of pollution and gas emissions like sulphate and nitrogen, which lead to haze, smog, and can poison waterways. Coal also produces mercury, which can contaminate sea life and therefore food sources. 


Continuing to burn coal for energy use creates many negative effects for the planet and our environment. Luckily, there is a solution, and it is available everywhere.

Renewable Energy Resources

Due to environmental concerns and the finite nature of fossil fuels, there has been an increase in adoption of renewable energy sources. Renewable energy resources are produced at a faster rate than they are consumed. They cannot be depleted, and they supply a continuous source of energy. The most common types of renewable energy include hydropower, wind power, and solar power. Two lesser-known sources are bio energy and geothermal energy. 


These resources are reliable and cleaner options than traditional fossil fuels. For instance, solar energy releases little to no carbon emissions when generating energy. Solar energy is the most accessible resource, available to individual homeowners and is a smart financial decision.

Up close view of solar panels, prior to installation, with cables and proper wiring elements

How Does Solar Work?

Solar power is created by the most reliable source – the sun and as a result is one of the cleanest and most sustainable forms of energy production. The solar energy journey begins with the sun’s light, which is made up of photons. Solar panels are negatively charged, and when positively charged photons contact the panels, they attract the electrons into a current – creating electricity. This current flows from the panel to an inverter, then to the central electricity unit. From there, it is distributed throughout the consuming appliances. 


Learn more about how solar works. 


Solar energy offers several advantages, including reduced environmental impact and independence from utility grids. It allows individual households to harness and produce their own electricity, which contributes to a more resilient and sustainable energy infrastructure.

Financial Benefits of Making the Switch to Solar

Coal-powered utilities have increased heavily in price and are projected to continue. Many homeowners are choosing to switch to renewable energy by installing PV systems, simply to avoid these price hikes and are saving thousands of dollars on utility bills. 


Solar power does not have to be constantly mined, burned, and transported to individual users; therefore, it cuts out significant costs. Because this source of energy is reliant on the sun, it produces on-site and abundant amounts of energy. 


There are several benefits to going solar; savings are only one.

Our Commitment to Clean Energy Access

At Blue Raven Solar, we believe all homeowners should power their homes with renewable resources. It is a great investment. The nation still relies on nonrenewable energy sources like coal, oil, or natural gas for more than half of its electricity, and we are pioneering the effort to bring solar to more people.  


As one of the top solar providers in the nation, we serve homeowners in these states and cities. Find out how installing a rooftop solar panel system can benefit your life and the earth today by getting a free quote from one of our solar experts!

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