The Advantages and Disadvantages of Coal as an Energy Source

11 minute read Graham Lumley Last update November 2023

coal mining and extraction

We’ve all heard about coal energy – good and bad. But what is coal energy, and how does it fit into our daily lives? In this article, we’ll take a closer look at coal energy, how it works, and how it impacts our environment. 

Frequently Asked Questions About Coal

Are there any alternative uses for coal, besides power generation?

Yes, there are alternative uses for coal besides power generation. Coal can be used in various industrial processes, including steel production, cement manufacturing, and chemical production. Coal can also be converted into synthetic gasses or liquid fuels through processes like coal gasification or coal liquefaction. However, these alternative uses of coal still have environmental implications, and efforts are being made to explore cleaner and more sustainable alternatives for these industrial processes.

How does the transportation and storage of coal impact the overall energy supply chain?

The transportation and storage of coal are essential components of the overall energy supply chain. Coal is typically transported via trains, trucks, or ships from mining sites to power plants or other end-users. This transportation process requires infrastructure, including rail lines, ports, and storage facilities. The transportation and storage of coal can have environmental impacts, such as the release of dust and pollutants during transportation or the potential for accidents or spills. Proper management, regulation, and investment in infrastructure are necessary to mitigate these impacts.

How does coal energy contribute to the economy and job creation?

Coal energy has historically played a significant role in the economy and job creation, particularly in regions with abundant coal reserves. Coal mining and the operation of coal-fired power plants have provided employment opportunities in the mining, energy production, and related industries. However, as the energy landscape shifts towards cleaner alternatives, job prospects in the coal sector have faced challenges. Economic diversification and transition strategies are being explored to support affected communities and facilitate the development of alternative industries.

Can coal energy be considered a sustainable source of power in the long term?

Coal energy is generally not considered a sustainable source of power in the long term due to its significant environmental impact and finite nature. Coal is a non-renewable resource, and its extraction depletes natural reserves over time. Moreover, coal combustion emits greenhouse gasses and contributes to air pollution and climate change. The increasing global focus on sustainable and low-carbon energy solutions has led to efforts to reduce coal dependency and transition towards cleaner alternatives.

What is the current global demand for coal energy, and how is it expected to change in the future?

The global demand for coal energy remains significant, although it varies among regions. Coal has historically been a dominant energy source, particularly in developing countries where industrialization and electricity demand are high. The demand for coal is expected to decline in the future due to efforts to transition to cleaner energy sources and address climate change concerns. The shift towards renewable energy, policy changes, and increasing focus on reducing carbon emissions are influencing the future trajectory of coal demand.

How does coal energy compare to other forms of energy, such as renewable sources?

Coal energy differs significantly from renewable energy sources in terms of environmental impact and sustainability. Unlike renewable sources like solar, wind, or hydropower, coal is a fossil fuel that emits significant amounts of greenhouse gasses when burned, contributing to climate change. Coal mining can have adverse effects on land, water quality, and ecosystems. Renewable energy sources, on the other hand, produce little to no greenhouse gas emissions during operation and have a much lower environmental footprint.

Are there any regulations or measures in place to mitigate the environmental effects of coal energy?

Yes, there are regulations and measures in place to mitigate the environmental effects of coal energy. Many countries have implemented air pollution control technologies and emission standards for coal-fired power plants to reduce the release of pollutants such as sulfur dioxide (SO2), nitrogen oxides (NOx), and particulate matter. Environmental regulations often require the implementation of technologies like flue gas desulfurization and electrostatic precipitators to reduce emissions. Some countries also have regulations for coal mining to minimize the environmental impact on land, water, and ecosystems.

How Burning Coal Produces Energy

Coal accounted for 19.5% of the electricity generated in the United States in 2022, down from 42% in 2014. In 2021, coal supplied 9.5 quadrillion British thermal units (2,800 TWh) of primary energy to electric power plants, which made up 90% of coal’s contribution to the U.S. energy supply. Utilities buy more than 90% of the coal consumed in the United States. There were over 200 coal-powered units across the United States in 2022. Coal plants have been closing since the 2010s due to cheaper and cleaner natural gas and renewables.

The U.S. Energy Information Administration (EIA) projects that coal will account for 13% of electricity generation in 2050. This decline is due to a number of factors, including the continued rise of natural gas and renewable energy, the implementation of environmental regulations, and the closure of coal-fired power plants.

What is Coal Used For? 

Coal is the most common fuel used to generate electricity in the United States. Coal-fired power plants burn coal to heat water, which turns into steam and drives a turbine to generate electricity. It’s also used to heat iron ore in blast furnaces in order to make steel and to produce chemicals like ammonia. 

Some homes are heated by coal via coal-fired boilers that heat water and circulate heat through a system of pipes.

How Coal is Formed

Coal is formed from the remains of plants that lived millions of years ago. It starts with the plants absorbing energy from the sun through a process called photosynthesis. Over time, when these plants die, their remains get buried under layers of soil and other debris.

As more and more layers build up, the plants’ remains undergo a transformation due to heat and pressure from the layers above. This process takes millions of years. The heat and pressure gradually squeeze out water and gasses from the plant material, leaving behind a substance called peat.

Over even more time, as additional layers of sediment continue to accumulate, the peat gets buried even deeper. The increased pressure and heat cause chemical changes in the peat, transforming it into different types of coal. This transformation process is known as coalification. The final product, coal, is a solid, black fossil fuel that can be burned to release energy.

Different Types of Coal: How Many Are There?

Coal comes in different types or ranks, which are anthracite, bituminous, sub-bituminous, and lignite. These ranks depend on the amount of carbon they contain and the heat energy they can produce. The rank of coal is determined by the pressure and heat that acted on the plants over a long time.

  • Anthracite is the highest rank of coal, containing 86% to 97% carbon. It has the highest heating value among all coal types. However, it makes up less than 1% of coal mining in the United States. Anthracite is mainly used by the metals industry and is mined in northeastern Pennsylvania.
  • Bituminous coal is the most common type of coal in the United States. It contains 45% to 86% carbon and is between 100 million and 300 million years old. Bituminous coal accounted for about 45% of total U.S. coal production in 2021. It is used to generate electricity and is important for making coking coal used in the iron and steel industry. The top five states for bituminous coal production are West Virginia, Pennsylvania, Illinois, Kentucky, and Indiana.
  • Subbituminous coal contains 35% to 45% carbon and has a lower heating value than bituminous coal. It is at least 100 million years old. About 46% of total U.S. coal production in 2021 was subbituminous, with Wyoming and Montana being the major producers. Some sub-bituminous coal is also mined in Alaska, Colorado, and New Mexico.
  • Lignite is the lowest rank of coal, containing 25% to 35% carbon. It has the lowest energy content among coal types. Lignite deposits are relatively young and were not subjected to extreme heat or pressure. It is crumbly and has a high moisture content, which reduces its heating value. Lignite accounted for 8% of total U.S. coal production in 2021. North Dakota and Texas are the primary producers, with smaller amounts coming from Louisiana, Mississippi, and Montana. Lignite is mostly used to generate electricity, but there is a facility in North Dakota that converts lignite to synthetic natural gas for use in natural gas pipelines in the eastern United States.

What is Coal Mining and How it Works

Coal mining is the process of extracting coal from the earth. Coal miners use large machines to remove coal from underground or near the surface. Some coal deposits, known as coal beds or seams, are located close to the earth’s surface, making them easily accessible. There are also coal deposits that are deep underground.

Surface Mining

Surface mining is a method commonly used when coal deposits are located relatively close to the surface, typically less than 200 feet underground. This type of mining involves the use of large machines that remove the topsoil and layers of rock, known as overburden, to expose the coal seams underneath. In some cases, mountaintop removal is employed, where the mountaintops are removed to access the coal seams beneath.

Surface mining is the preferred method for about two-thirds of coal production in the United States because it is generally more cost-effective compared to underground mining.

Underground Mining

Underground mining, also known as deep mining, is used when the coal deposits are located more than 200 feet below the surface. Some underground mines can be incredibly deep, with tunnels extending for miles from vertical mine shafts. Miners descend into the deep mine shafts using elevators and then travel through long tunnels on small trains to reach the coal seams. Large machines are used by the miners to dig out the coal from these underground deposits.

Environmental Impacts of Coal Mining

Coal is an affordable and widely available fuel source, but there is an environmental trade-off. Surface mining, also known as strip mining, accounts for about 62% of coal mining in the United States. As we’ve explained, operations involve removing the soil and rocks covering coal deposits. The largest surface mines are found in Wyoming’s Powder River Basin, where coal deposits are close to the surface and can be up to 70 feet thick.

  • Mountaintop removal and valley fill mining have had a significant impact on the Appalachian Mountains in states like West Virginia and Kentucky. This method involves using explosives to remove the tops of mountains, resulting in a changed landscape. 
  • Streams in the area may be covered with rock and dirt, leading to water pollution that can harm aquatic life downstream. 
  • Mountaintop mining became more widespread and controversial starting in the 1990s, even though it has been practiced since the 1970s.
  • U.S. laws require that dust and water runoff from coal mining areas be controlled, and the affected areas must be restored as close to their original condition as possible.
  • Underground mines generally have less impact on the landscape compared to surface mines, but the ground above mine tunnels can collapse, and acidic water can drain from abandoned underground mines.
  • Methane gas, which is found in coal deposits, can be explosive when concentrated in underground mines. In 2020, methane emissions from coal mining and abandoned mines accounted for about 7% of total U.S. methane emissions and about 1% of total U.S. greenhouse gas emissions. 
  • Burning coal results in several major emissions, including sulfur dioxide, nitrogen oxides, carbon dioxide, mercury, fly ash, and bottom ash. According to the U.S. Energy Information Administration, CO2 emissions from burning coal for energy accounted for about 20% of total U.S. energy-related CO2 emissions and nearly 60% of total CO2 emissions from the electric power sector in 2021.

How Does the Processing and Transportation of Coal Work?

After coal is mined, it’s processed and then transported to consumers in a number of ways: 

Coal Processing

Once the coal is extracted from the ground, it is often taken to a nearby preparation plant for cleaning and processing. This plant removes unwanted materials like rocks, dirt, ash, sulfur, and others to enhance the quality and heating value of the coal.

Coal Transportation

Transporting coal can be costly compared to mining it. To reduce transportation expenses, some coal consumers, such as coal-fired power plants, are strategically located near coal mines. 

Conveyors, trams, and trucks are used for short distances within mines or to nearby consumers, but most coal (70%) is transported via rail. Barges and ships are sometimes used to transport coal across lakes, rivers, and oceans. 

Slurry pipelines, although not currently utilized in the United States, can transport a mixture of crushed coal and water.

Coal as an Energy Source

Coal is the second-largest energy source in the U.S. for electricity generation (around 22%). A few coal-fire plants convert coal to a gas which can be used in gas turbines to generate power; others use steam turbines. 

How Many Coal Power Plants in the US?

Coal power stations, also known as coal-fired power plants or coal plants, are facilities that generate electricity by burning coal. They are large industrial complexes designed to efficiently convert the energy stored in coal into electrical energy.

As of 2023, there are 224 operational coal-fired power stations in the United States. These plants have a total capacity of 256 gigawatts (G.W.), which is about 19% of the country’s total electricity-generating capacity.

Environmental Impact of Coal Power Stations

Burning coal in power plants leads to the release of carbon dioxide (CO2) emissions, which contribute to climate change. 

Coal-fired power plants use technologies like “scrubbers” to remove pollutants from their emissions before they are released through smokestacks. However, the smoke still contains nitrogen oxides, sulfur dioxide, particulate matter (like soot), and heavy metals such as mercury, which can impact air quality and human health, even at considerable distances from the power plants.

Due to the U.S. Environmental Protection Agency’s Clean Power Plan and the low cost of natural gas, older coal plants are closing, and interest in new coal plants is declining.

Recent Advancements in Coal Technology

Burning coal releases a lot of carbon dioxide (CO2) into the atmosphere, contributing to global warming. To address this issue, scientists are developing new technologies that aim to reduce or eliminate CO2 emissions. However, these technologies are expensive and energy-intensive, so it’s unsure whether they will be viable in the future.

Clean Coal Technology

Some existing methods to make coal cleaner include washing it to reduce emissions of ash and sulfur dioxide when burned, using electrostatic precipitators and fabric filters to remove fly ash from flue gasses, and employing flue gas desulfurization to reduce sulfur dioxide emissions. Low-NOx burners, re-burning techniques, and selective catalytic reduction can also help reduce nitrogen oxide emissions. Newer coal plants are more efficient, producing fewer emissions per unit of electricity generated. Advanced technologies like integrated gasification combined cycle (IGCC) and pressurized fluidized bed combustion (PFBC) can further increase efficiency.

There are also efforts to produce ultra-clean coal (UCC) with very low levels of ash and sulfur, which could be used as fuel in large marine engines. Gasification and sequestration technologies are being explored as well.

Carbon Capture and Storage

Carbon capture and storage (CCS) is a key aspect of ‘clean coal,’ involving capturing CO2 and storing it underground. Several methods exist for capturing CO2, but they are not yet optimized for large-scale coal power plants.

Early developments in carbon capture and storage (CCS) focused on capturing CO2 emissions from a single source and storing them in a specific location. However, as economies of scale became important, the focus shifted to creating hubs that collect, dehydrate, and transport CO2 from multiple sources. Currently, there are around 15 such hubs being established.

The Northern Lights Project in the North Sea, led by Equinor, Shell, and Total, is one of the most advanced hubs. It gathers CO2 emissions from various plants, initially around 0.8 million tonnes per year and later increasing to about 5 million tonnes per year. The CO2 is compressed, liquefied, and transported by dedicated ships to a storage site. The project aims to start operating in 2024.

What are the Challenges of Coal Energy (and Potential Solutions)?

Coal production and usage have slowed down as cleaner and more affordable alternatives for generating electricity have emerged. Although this transition away from coal can be challenging for communities that rely on coal mines and plants, it is crucial to mitigate the severe impacts associated with coal.

air pollution from coal power plant

Air Pollution

When coal is burned, it releases various harmful pollutants into the air, such as mercury, lead, sulfur dioxide, nitrogen oxides, and particulates. These pollutants are linked to health issues like asthma, respiratory problems, heart diseases, cancer, neurological disorders, and premature death. Although the Environmental Protection Agency has set emission limits, many power plants lack the necessary pollution controls, and the future of these protections remains uncertain.

Climate Change and Global Warming

Coal mining and power plants have significant effects on water sources. Coal ash, similar to the ash from a charcoal grill, is produced in large quantities by coal-fired power plants, with over 100 million tons generated annually. A considerable portion of this waste ends up in landfills, ponds, lakes, and other sites, posing a risk of water contamination over time. Coal mining also leads to acid rock drainage, destruction of mountain streams and valleys through mountaintop removal mining, and conflicts over water resources when coal plants rely heavily on local water supplies.

One of the most serious long-term global impacts of coal usage is its contribution to climate change. When coal is burned, it releases carbon dioxide, a greenhouse gas that traps heat in the atmosphere. This leads to adverse consequences such as droughts, rising sea levels, floods, extreme weather events, and loss of species. The severity of these impacts is directly related to the amount of carbon dioxide emitted, including from coal plants. In the U.S., coal power plants account for roughly one-quarter of energy-related carbon emissions.

Sustainable Alternatives to Coal Energy

One sustainable alternative to coal is natural gas. Natural gas is a cleaner burning fossil fuel compared to coal, emitting fewer pollutants and greenhouse gasses when burned. It produces lower levels of sulfur dioxide, nitrogen oxides, and particulate matter, which contribute to air pollution and respiratory issues. Natural gas combustion releases fewer carbon dioxide emissions, resulting in reduced contributions to climate change.

Natural gas can be used as a transition fuel in the shift towards renewable energy sources. It can complement intermittent renewable energy generation, such as wind and solar, by providing a reliable and flexible source of power for electricity generation. Natural gas power plants can quickly ramp up or down their output, helping to stabilize the electrical grid when renewable energy production fluctuates.

Renewable energy sources provide sustainable alternatives to coal. These sources harness energy from natural processes such as sunlight, wind, water, and heat from the Earth’s core. They produce clean electricity without emitting greenhouse gasses or contributing to air pollution.

Nuclear power generates electricity through controlled nuclear reactions. It produces significant amounts of energy without greenhouse gas emissions. However, the use of nuclear power raises concerns about the safe disposal of radioactive waste and the potential for accidents, making it a controversial option.

Biomass energy utilizes organic materials such as wood, agricultural waste, or dedicated energy crops to produce heat or electricity. Biomass can be burned directly or converted into biofuels like ethanol and biodiesel. When sustainably sourced, biomass energy can be carbon-neutral since the carbon emitted during combustion is absorbed by newly grown plants.

Conclusion

Going back to our earlier question: what is coal energy? It’s not a sustainable energy source for the future, even though it’s so widely used. While scientists and engineers are hard at work to ensure that coal is as clean as possible, the current solutions are still very expensive and not economically viable. Instead, we have to look at alternatives that are affordable but cleaner-burning. 

The Future of Coal Energy

Currently, coal remains a significant contributor to global electricity generation, accounting for a little over one-third of the total. It also plays a vital role in industries like iron and steel. However, as we strive towards achieving the IEA’s Net Zero Emissions by 2050 Scenario, it is crucial to transition away from unabated coal generation by 2040.

To align with the Net Zero by 2050 Scenario, we must aim for an annual average reduction of approximately 8% in emissions from coal-fired power plants until 2030. This reduction is necessary to stay on track and meet our emissions targets. In order for coal to have a place as a cleaner energy source in the future, governments and the coal industry must collaborate to develop and deploy technologies that are less polluting and more efficient.