Coal

Coal is a combustible black or brownish-black sedimentary rock. It forms in layers called coal seams. It is mostly carbon with some other elements, such as hydrogen, sulfur, oxygen, and nitrogen. Coal is a fossil fuel. It forms when plants decay into peat. Over millions of years, heat and pressure turn peat into coal. Big deposits of coal came from wetlands called coal forests. These covered much of the tropics during the late Carboniferous and early Permian periods.

Coal is mainly used as a fuel. People have used coal for thousands of years, but it became more important during the Industrial Revolution. The invention of the steam engine made coal very useful. In 2020, coal provided about a quarter of the world's primary energy and over a third of its electricity. Some iron and steel making and other industries also burn coal.

Using coal can harm the environment and health. It is the biggest source of carbon dioxide, which helps cause climate change. Many countries are working to use less coal. The United Nations Secretary General asked governments to stop building new coal plants by 2020.

In 2024, a record amount of coal was burned. But use of coal is expected to peak before 2030. To meet the Paris Agreement goal of keeping global warming below 2 °C (3.6 °F), coal use needs to drop sharply. This was agreed upon in the Glasgow Climate Pact.

China uses and imports the most coal. China mines almost half of the world's coal. India uses about a tenth. Indonesia and Australia export the most coal, followed by Russia.

Etymology

The word for coal is very old. It started as col in Old English. This came from an even older language called Proto-Germanic. The word looks similar in other old languages, like kole in Old Frisian, cole in Middle Dutch, and kohle in German today.

Formation of coal

The process of turning dead plants into coal is called coalification. Long ago, Earth had thick forests in wet, low-lying areas. When plants died in these places, they were protected from breaking down by layers of mud or water. This allowed them to turn into peat, which is the first step in making coal.

Over millions of years, these peat layers were buried deeper under sand and mud. The heat and pressure from this burial changed the peat into coal. The type of coal that formed depended on how much heat and pressure were applied. Lighter, softer coal called lignite formed with less heat and pressure, while harder, denser coal like anthracite coal needed more. Most of the world's coal formed during a time called the Carboniferous period, when the climate and land conditions were just right for making lots of coal.

History

Further information: History of coal mining

People have used coal for thousands of years. The oldest known use of coal was found in a place called Ostrava, Petřkovice, from around 25,000–23,000 years ago. In China, people began using coal around 4000 BC to make ornaments, and later to smelt copper. Famous traveler Marco Polo described coal in the 13th century as “black stones … which burn like logs.”

In Europe, early uses of coal date back to the Bronze Age around 3000–2000 BC in Britain, where it was used in funeral fires. The Romans used coal in places like England and Wales for heating and metalworking. By the 13th century, coal, sometimes called “seacoal,” was being shipped to London for building and other uses. As easier-to-reach coal ran out, people began mining underground.

The Industrial Revolution saw coal become a key energy source, powering steam engines. Britain was a major coal producer, and coal remained important for industry through the 19th and 20th centuries.

Composition

Coal is made from many different plant materials and comes in several types. Younger coals, like brown coal and lignite, are not completely black. The two main black types are bituminous coal, which is more common, and anthracite, which has the most carbon. Anthracite has the most energy, followed by bituminous coal, lignite, and brown coal. Some anthracite contains pure carbon in the form of graphite.

Bituminous coal is mostly carbon, with smaller amounts of hydrogen, oxygen, nitrogen, and sulfur. These come from the plants that formed the coal long ago. Coal also contains ash, which is made of minerals that do not burn. The amount of sulfur in coal can vary, and when coal is burned, it can release gases. Some sulfur can be removed before burning by special processes. Coal also has small amounts of other minerals.

Uses

Most coal is used to give us energy. Coal has a lot of energy; it takes about 325 kilograms of coal to power a 100-watt lightbulb for a whole year.

Electricity generation

Most of the world's coal is burned to make electricity. Coal is burned in power stations, called thermal coal, and this creates steam that spins turbines to make electricity. Some newer plants use a process called integrated gasification combined cycle (IGCC), which burns coal more efficiently.

Coke

Main article: Coke (fuel)

Coke is made from coal by heating it without air. It is very important for making steel because it helps turn iron ore into iron. Coke is grey, hard, and can produce a lot of heat.

Production of chemicals

We have made chemicals from coal since the 1940s. Coal can be turned into syngas, a mix of gases, which is used to make many everyday products like plastics and fertilizers.

Liquefaction

Coal can be turned into liquid fuels like gasoline or diesel. This usually creates more carbon dioxide than making fuel from oil.

Gasification

Coal gasification turns coal into syngas, which can be used to make electricity or turned into fuels like gasoline. This process mixes coal with oxygen and steam under heat and pressure.

Coal industry

Main pages: Category:Coal companies, Coal mining, Coal by country, Coal industry in China, Coal industry in Pakistan, Coal industry in India, and Coal companies of Australia

Coal is dug up from the earth in places called mines. A lot of coal comes from deep underground mines. Coal can be used to make electricity. Some special kinds of coal help make metal.

Countries like China and India dig up lots of coal. Indonesia sends the most coal to other countries. Australia and Russia send a lot too. People buy and sell coal like other goods. Its price can change a lot. Some places are starting to use wind and sun power instead of coal.

Damage to human health

Burning coal can cause health problems. It releases harmful substances into the air, such as nitrogen oxides, sulfur dioxide, and tiny particles that can get into our lungs. These can lead to health issues like asthma, heart problems, and lung cancer.

Coal mining and processing can also pollute water and air, affecting people living nearby. Breathing in coal dust can damage the lungs. Coal plants produce waste called coal ash, which contains harmful materials that can hurt people and the environment.

Damage to the environment

Main article: Environmental impact of the coal industry

Coal mining and burning coal can hurt the environment in many ways. Mining can change the level and acidity of groundwater and water tables. Spills from power plants can pollute land and water and damage homes. Power plants that burn coal also use a lot of water. This can affect rivers and other land uses, especially in dry areas like the Thar Desert in Pakistan.

Burning coal releases sulfur dioxide, which can lead to acid rain. This rain can harm plants, animals, and water systems. Old coal mines can also cause problems, like the land sinking above tunnels or starting fires that burn for many years.

Climate change

The biggest long-term effect of using coal is that it releases carbon dioxide, a gas that causes climate change. Coal power plants were a big source of growth in global carbon dioxide emissions in 2018. For every unit of electricity made, coal releases about twice as much carbon dioxide as natural gas. To help stop the world from warming too much, many coal power plants will need to close early.

Underground fires

Thousands of coal fires burn around the world. These fires can be hard to find and stop. They can make the ground sink and release dangerous gases. Coal can catch fire on its own or from lightning strikes, and once it starts burning, it can continue until it runs out of oxygen.

Pollution mitigation and carbon capture

There are ways to lessen the harm that comes from burning coal for energy. These methods help protect both people and the environment.

One way is to treat the coal before it is burned. This can remove extra water and some harmful substances, making the coal burn better and produce fewer bad gases.

Another way is to clean the gases after the coal is burned. Special machines can catch many of the harmful gases and particles that come out of coal power plants.

Carbon capture and storage is a method that catches a gas called carbon dioxide from coal power plants and puts it deep underground where it cannot hurt the air. Even with these helpful technologies, coal still causes harm to the environment.

Economics

In 2018, about US$80 billion was used to keep coal mines running.

China makes the most coal and uses it for about 60% of its energy. Many of China's coal power stations are not making money. Air pollution from coal can cost money and hurt people. Cutting air pollution helps both people and the economy.

Politics

Some countries, like China, India, Indonesia, Vietnam, Turkey, and Bangladesh, have been building new power plants that burn coal. This has caused concern from other countries, especially islands like Vanuatu and Fiji. These islands worry about rising sea levels.

In 2021, the G7 countries agreed to stop giving support for new coal power plants.

These efforts to reduce coal use are linked to the goals of the Paris Agreement to protect the environment.

Cultural usage

Coal is the official state mineral of Kentucky, and the official state rock of Utah and West Virginia. These US states have a long history with coal mining.

In some traditions, children who do not behave well might get a lump of coal instead of gifts from Santa Claus when they wake up on Christmas morning with their stockings ready. In Scotland, it is a special custom to give coal as a gift on New Year's Day as part of first-footing. This brings good luck and warmth for the year ahead.