Coal-fired power station

A coal-fired power station is a special kind of power plant that uses coal to make electricity. It works by burning coal in a very hot furnace. This heat turns water into steam, and the steam spins big machines called turbines. These turbines then power generators, which create electricity for our homes and cities.

There are about 2,500 of these plants around the world, and together they make around a third of all the electricity we use. However, they also cause a lot of health problems and early deaths because of the air pollution they create. They are also a big reason why our planet is warming up, releasing huge amounts of carbon dioxide into the air every year.

Even though some countries are starting to stop using coal, many new plants are still being built, especially in parts of Asia. This makes it important for us to think about cleaner ways to make electricity that don’t hurt our health or the environment.

History

See also: Power station § History

The first coal-fired power stations were built in the late 1800s. They used special engines to create electricity. Later, bigger plants were made using steam turbines, which helped provide electricity to larger areas.

Transport and delivery of coal

Coal can be brought to power stations in many ways, such as by trucks on highways, by rail, on barges, by collier ships, or through special coal slurry pipelines. Sometimes, power stations are built very close to coal mines, especially for types of coal like lignite that aren't worth transporting far. In these cases, coal might arrive by conveyor belt or in large diesel-electric-driven trucks.

Very long trains, called “unit trains,” can be over 2 kilometers long and carry more than 10,000 tonnes of coal in one trip. Big power plants need at least one of these huge trains each day, and sometimes they get three to five trains a day, especially during very hot or very cold weather when people use more electricity.

Operation

See also: Thermal power station

A coal-fired power station turns coal into electricity by using heat. First, coal is broken into tiny pieces and burned. This heat turns water into steam. The steam spins big machines called turbines, which then power generators to make electricity.

Coal power stations need special ways to handle the leftover ash from burning coal. This ash is often stored in special ponds or landfills to keep it from harming the environment. Some of these ashes can even be reused in building materials.

Coal power generation

Two-thirds of the coal we burn is used to make electricity. In 2020, coal was the biggest source of electricity around the world, providing about 34% of all the power we use. China, India, and Indonesia got most of their electricity from coal.

In 2020, the world had about 2,059 GW of coal power stations working. By 2023, this grew to 2,130 GW, mostly because China added more. Some countries promised to stop using coal at a meeting in 2021, but many places, especially developing countries like Indonesia and Vietnam, still face big challenges in changing away from coal.

Efficiency

Coal-fired power stations come in four main types, listed from least efficient to most efficient: subcritical, supercritical, ultra-supercritical, and cogeneration (also called combined heat and power or CHP). Subcritical plants are the least efficient, but new improvements have helped older subcritical plants become just as efficient as supercritical plants.

Integrated gasification combined cycle design

Main article: Integrated gasification combined cycle

Integrated gasification combined cycle (IGCC) is a way to make electricity from coal. It uses a special machine called a gasifier to turn coal into a gas. This gas can then be used in a combined cycle generator, which usually makes electricity more efficiently. IGCC can also help remove some harmful substances from the gas before making electricity. But this method costs more money than regular coal power plants.

Carbon dioxide emissions

See also: Fossil fuel power station § Carbon dioxide

Coal-fired power stations release a lot of a gas called carbon dioxide, which is bad for the environment. They produce more of this gas than most other ways we make electricity. In 2018, these stations released over 10 billion tons of carbon dioxide into the air.

Mitigation

Phase out

See also: Coal phase out

Some older coal power stations are being shut down, but new ones are still being built in some places. In 2020, the amount of electricity made from coal went down a little, but it went back up again in 2021. Leaders have said that we need to stop using coal to make electricity by certain years to help protect our planet.

Ammonia co-firing

See also: Ammonia

Scientists are testing a new way to use a substance called ammonia to help cut down on carbon dioxide from coal power stations. This is being tried in Japan.

Conversion

Some power stations are changing so they can burn things like gas, plant material, or waste instead of coal.

Carbon capture

See also: Carbon capture and storage

Some people think we could add special equipment to coal power stations to catch the carbon dioxide, but this is very expensive and might not work for all stations.

Pollution

Main article: Environmental impact of the coal industry

Coal-fired power plants create harmful smoke that can make people very sick. This smoke contains tiny particles that can get into our lungs and bodies, causing problems like breathing difficulties, heart issues, and even some diseases. In the United States alone, these tiny particles have been linked to many early deaths over many years.

Some places have rules to try to reduce this pollution, but in other countries, coal plants still cause many early deaths each year. Burning coal can also pollute water with dangerous metals, which can harm animals and fish in rivers and lakes. These metals can stay in the environment for a very long time.

Economics

Coal power plants are often used as a steady source of electricity because they can run almost all the time. However, this makes them less flexible in changing market conditions.

In 2020, the coal industry received $18 billion in subsidies.

The financing of coal projects, including power plants and mining, has raised concerns because it may conflict with international climate goals, such as those in the Paris Agreement. The Paris Agreement aims to limit global warming to well below 2 degrees Celsius. Supporting coal projects can make it harder to reach these goals.

Some countries have supported coal projects overseas, which can create long-term climate and financial risks. As renewable energy becomes more affordable, the economic benefits of coal projects decrease. There is a growing push for stronger policies to limit the financing of coal projects to better support climate efforts.

In India, coal power plants often run at less than 60% of their maximum capacity. In the United States, coal plants operated at around 40% of their capacity in 2020.

If global warming is limited to well below 2 °C, over $500 billion worth of coal plants may become unprofitable by 2050, especially in China. Some experts believe that many coal plants are already more expensive than new renewable energy options.

Politics

In May 2021, the G7 agreed to stop supporting coal-fired power stations. This is important because their use of coal dropped from 23% in 2015 to 15% in 2023. However, countries like China and India still rely heavily on coal for energy.

As of 2023, the Group of Twenty (G20) controls most of the world's coal power stations. The decisions made by China about coal will greatly affect the future of these power stations, as the country has many of them.

People have also protested against coal mining and new power plants in places like Hambach Forest, Akbelen Forest, and Ffos-y-fran.