Coal: Composition, Uses, Figures and Debates

Coal, often regarded as the dirtiest of all fossil fuels, has played a vital role in powering industrial progress and shaping modern society. Formed from plant matter over millions of years, its main uses include electricity generation, steel production, and cement manufacturing. However, due to its significant environmental impact, there is a growing movement to reduce its use. In recent years, this has led to a global shift towards more sustainable energy sources and an increasing call for the complete phase-out of coal.

👉 In this article, we explore coal's composition, uses, and the growing global efforts to phase it out due to its environmental impact.

Coal is a naturally occurring combustible rock and fossil fuel. It’s primarily made up of carbon, along with a smaller amount of other elements, mainly: hydrogen, sulphur, oxygen, and nitrogen. It’s formed from the remains of vegetation that has been subjected to geological heat and pressure over the course of millions of years. This is what’s known as coalification; it involves the gradual transition of plant matter into peat, which then transforms into coal under increased heat and compression.

There are several types of coal, each with distinct characteristics, based on their carbon content, energy density, and the conditions under which they were formed. The four main types include lignite, subbituminous bituminous coal, and anthracite, representing different stages in the coalification process.

Lignite

Lignite, often referred to as "brown coal," is the lowest rank of coal and is the first to form. With a relatively low carbon concentration of 25 to 35%, lignite retains a high moisture content and a low energy density. It is typically brownish-black in colour and has a crumbly texture. Due to its lower energy content and higher emissions, lignite is often used in electricity generation where it is mined, minimising transportation costs.

Subbituminous

Subbituminous coal consists of around 35 to 45% carbon and is known for its lower sulphur content and higher energy value than lignite. It’s primarily used for electricity generation and possesses cleaner burning properties than lower-grade alternatives. 

Bituminous

Bituminous coal is the most abundant form of coal. It contains a higher carbon content of 45 to 86%, which makes it denser and gives it a higher energy content. Bituminous coal is used extensively in power generation, steel production, and as a fuel in industrial processes. It varies in colour from dark brown to black and has a relatively high heat value. This type of coal also has sub-categories, including low, medium, and high volatile, each indicating the amount of gas it contains, which affects its burning properties.

Anthracite

Anthracite, the highest grade of coal, boasts the highest carbon content (86 to 97%). It is hard and black with a shine to it. Due to its high carbon content and low impurities, anthracite burns cleaner than other coal types, making it a preferred choice for residential heating. However, it is less abundant than other coal types and is more expensive to mine.

Metallurgical 

One other coal type that is worth mentioning is metallurgical coal, or coking coal, which is crucial in steel production for its ability to be converted into coke - a necessary component in the steelmaking process. Its unique caking properties (ie. its ability to form a cohesive mass when heated without air) and low sulphur content set it apart from other coals primarily used for energy generation.

How is coal formed? 

Geologically, coal formation begins with the build-up of plant material in swampy environments. Over time, this organic matter is buried under sediments, where it undergoes chemical and physical changes due to the increased pressure and temperature. Over time the plant matter changes into a moist, low-carbon peat, before eventually transforming into coal. This transformation is a gradual process, taking millions of years, and results in the variety of coal types seen today, each with its unique properties and uses.

Coal has been central to industrial progress for centuries. Historically, coal was mainly used for heating and cooking, but during the Industrial Revolution, its use expanded dramatically. Coal was used to fuel steam engines, driving the expansion of railways and industrial machinery. To this day coal continues to be used in industrial processes; it is primarily used in electricity generation, steel production, and cement manufacturing.

• Electricity generation - Coal is used to generate electricity across the world. Power plants burn coal to heat water in boilers, creating steam. This steam then spins turbines connected to generators, producing electricity. Despite growing environmental concerns and the shift towards renewable energy sources, coal remains a significant contributor to global electricity, especially in developing countries where it's a more accessible and cost-effective option.
  
• Steel production - Coal is crucial to steel production, particularly in the form of coke, a high-carbon, low-impurity fuel. In steelmaking, coke serves as a reducing agent in blast furnaces, facilitating the conversion of iron ore into iron. It also provides the required heat for the smelting process. The steel industry's reliance on coal makes it one of the largest industrial consumers of this fossil fuel.
  
• Cement manufacturing - Coal is also important in cement production. It is used to heat the cement kiln to temperatures necessary for the calcination process, where limestone and other materials are transformed into clinker, the core ingredient in cement. The high temperatures required for this process make coal an ideal fuel, given its high energy content.

Despite its usefulness in a variety of different industrial processes, coal's usage faces increasing scrutiny due to its environmental impact. This has led to a gradual shift towards more sustainable energy sources. However, coal's significance in the global energy landscape continues, particularly in regions where alternatives are not yet viable.

💡 Did you know? Coal accounts for over one-third of global energy generation, even though it’s the most carbon-intensive fossil fuel. 

Coal remains a significant player in the global energy market, despite the growing emphasis on renewable energy sources. Let's take a look at the key statistics that showcase its production and consumption patterns.

Top coal-producing countries

China leads the world in coal production, accounting for a significant portion of global output - in 2022, China accounted for over 52% of coal production worldwide! It’s followed by countries like India, the United States, Australia, and Indonesia. These nations not only satisfy their domestic energy needs but also contribute substantially to the global coal export market, with Australia and Indonesia being most notable for their coal exports.

Largest coal reserves

The United States holds the world's largest coal reserves, followed by Russia, Australia, and China. These vast reserves mean that there is significant potential for continued coal production - although the extent to which these reserves are extracted depends on national and global energy policies and market demands. The United States for example recently joined a growing group of nations (known as the Powering Past Coal Alliance) in committing to building no new coal plants and phasing out existing plants. 

Global consumption trends

In recent years, there has been an overall decline in coal use in regions like Europe and North America, largely due to environmental concerns, environmental policies and the switch to cleaner energy sources. However, in Asia, particularly in countries like China and India, coal consumption has continued to grow, driven by rapid industrialisation and energy demands. This expansion means that despite moves to phase out coal use in other countries, we’ve seen an overall increase in global coal consumption of 3.3% in 2022.

The environmental impact of coal is significant, posing substantial risks to the Earth's climate, air quality, and public health. Let’s take a closer look at the damaging effects of coal: 

Environmental impact of coal

Coal mining, particularly through surface mining techniques like strip mining and mountaintop removal, leads to significant environmental degradation. These methods involve removing large areas of land cover and soil, leading to deforestation, soil erosion, and the disruption of local ecosystems. The loss of vegetation also impacts biodiversity, as habitats are destroyed or fragmented.

Subsurface mining (ie. mining that takes place below the surface of the Earth) might be less visually damaging, however, it carries its own environmental risks. These include the potential for mine collapses and subsidence, which can also impact the surface through the disruption of landscapes and damage to buildings and infrastructure. 

Another particularly concerning issue with subsurface mining is the generation of acid mine drainage - a process where water passing through mine waste acquires high concentrations of acids and heavy metals. This contaminated water can seep into streams and rivers, posing serious risks to aquatic life and water quality.

Coal and air pollution

The burning of coal - especially in power plants and industrial processes - is a significant source of air pollution. Coal combustion emits sulphur dioxide (SO2) and nitrogen oxides (NOx), which are primary contributors to the formation of acid rain and ground-level ozone or smog. These pollutants can severely impact human health, ecosystems, and agricultural productivity.

Particulate matter - another byproduct of coal combustion - also presents a health risk. These tiny particles can penetrate deep into the lungs and bloodstream, exacerbating respiratory and cardiovascular diseases. Additionally, coal plants emit heavy metals like mercury, which can accumulate in the food chain, posing risks to both wildlife and humans.

Coal and climate change

Coal's role in climate change is undeniable. As the most carbon-intensive of all fossil fuels, coal combustion is a major contributor to global greenhouse gas emissions. In fact, coal is responsible for over 0.3 degrees of the 1 degree Celsius increase in global average temperatures, making it the largest single source of climate change. And the impact of coal shows no signs of stopping - it continues to contribute around 40% of global greenhouse gas emissions every year! 

These emissions are a driving force behind global warming and its associated climate impacts, like rising sea levels, increased extreme weather events, and shifts in the planet’s ecosystems.

Health impacts of coal

Beyond its environmental effects, coal also poses direct risks to human health. Populations close to coal mines and power plants are often exposed to higher levels of pollutants, leading to increased incidences of respiratory ailments, heart disease, and other health problems. These issues are not just medical concerns but also raise questions of environmental justice, as the health burdens often fall disproportionately on lower-income and marginalised communities.

👉 To learn more about the negative impacts of fossil fuels head over to our article. 

Although the detrimental impact of coal on the environment and human health is widely recognised, the scenario is more complex when considering developing nations. Here, coal's role is intricately linked with economic development, energy accessibility, and the overarching challenge of climate change, making the issue particularly challenging to address. These nations face the complex task of balancing immediate developmental needs with long-term sustainability goals.

Why developing nations often use coal

Coal is a popular energy source in many developing countries due to its abundance and cost-effectiveness. For countries with significant coal reserves, it represents a domestically available resource, reducing reliance on imported fuels and contributing to energy security. Moreover, the existing infrastructure in many of these countries is heavily geared towards coal, making it a readily available option for electricity generation and industrial use.

Balancing development and climate change

Developing nations are often at a crossroads where they must elevate living standards and propel economic growth while being mindful of their environmental impact. Coal has historically been a driver of industrialisation, offering a pathway to improve living standards. However, its usage poses significant environmental challenges, contributing to local air pollution and global greenhouse gas emissions.

The dilemma for these nations is stark: how to provide affordable, reliable energy to their growing populations and industries without exacerbating climate change. This balancing act is complicated by the fact that many developing countries are more vulnerable to the impacts of climate change, such as extreme weather events and rising sea levels, even though their historical contribution to global emissions is relatively small.

Difficulties in switching to renewables

Transitioning to renewable energy sources like solar, wind, and hydro presents several challenges for developing nations. The main issues include the high upfront investment costs, the need for technological transfer and capacity building, and the intermittency of renewable energy sources which often require expensive energy storage solutions. Additionally, developing a comprehensive and reliable renewable energy infrastructure takes time - something that many fast-growing economies don’t have when immediate energy needs are pressing.

The development argument

There is also a strong argument that developing nations should be allowed the same opportunity to use coal and other fossil fuels for their economic growth, as industrialised nations have had. Critics argue that developed countries achieved their economic growth through the use of fossil fuels, and it would be unfair to deny developing countries the same opportunity, especially when alternatives are not yet fully accessible or affordable.

👉 Find out more about the link between economic growth and emissions in our article. 

Why does coal need to be phased out? 

Climate experts underscore the urgency of phasing out coal to mitigate the impacts of climate change, emphasising that it is a critical step in meeting global emissions targets. According to the Intergovernmental Panel on Climate Change (IPCC), to limit global warming to 1.5°C above pre-industrial levels - a key goal of the Paris Agreement - we must reduce coal consumption by three quarters between 2020 and 2030. 

The IPCC has also stated that coal-fired electricity generation needs to fall by 80% below 2010 levels by 2030 to stay on track for net zero emissions. This aligns with the United Nations' call for OECD countries to phase out unabated coal power by 2030 and for the rest of the world to do so by 2040.

Is there an international consensus on the phase-out of coal? 

In recent years there’s been a concerted effort by countries to transition to cleaner energy sources and away from fossil fuels. Initially, only a few countries committed to moving away from coal. However, momentum built after the establishment of the Powering Past Coal Alliance (PPCA) in 2017, spearheaded by Canada and the UK. 

The PPCA now has 60 member countries, reflecting a growing international commitment to abandon coal. This commitment is further reinforced by individual nations' pledges under the UN Framework Convention on Climate Change (UNFCCC) and other international and national agreements. 

The commitment to a transition away from coal was solidified in 2021 at COP26 in Glasgow, where 46 countries signed the Global Coal to Clean Power Transition Statement. This agreement marked a significant step, with countries either agreeing to stop new coal-fired power plant permits or committing to phase out coal in the 2030s for major economies and in the 2040s for others. 

The momentum continued at the recent COP28, where the final agreement called for a “transition away from fossil fuels” and a rapid phase-down of unabated coal use. The text also called for a substantial increase in renewable energy capacity and improvements in energy efficiency by 2030. Notably, the Powering Past Coal Alliance saw significant expansion during COP28, with new members joining, including the United States, UAE, Czech Republic, Cyprus, Dominican Republic, Iceland, Kosovo, Malta, and Norway. 

These collective efforts underscore a clear and growing international resolve to move away from fossil fuels, towards a more sustainable and environmentally responsible future.

👉 Discover whether phasing out fossil fuels is a fantasy or a realistic target over on our blog.

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