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Coals: Back to basics

Throughout the website you'll see numerous references to terms such as "manufactured coal" and "different types of coal" without knowing too much about them. We've put together a list of essential questions we get asked about coal, which should help to explain what it is, where it comes from and everything else you need to know about this type of solid fuel.

1. What is coal?

2. How is coal formed?

3. How does it burn?

4. How long has coal been used?

5. How do we get coal?

6. Are there different types of coal?

7. How does one type of coal differ from another?

8. What is manufactured coal?

9. Are there eco-friendly coals?

10. Are there still coal pits in the UK?

11. What is the best type of coal?


What is coal?

Coal is a burnable solid fuel found in underground deposits across the world. Made up largely of carbonised plant matter, coal is generally a black or dark brown rock. Coal is now commonly used as a fuel to help homeowners heat their homes.

How is coal formed?

Coal is called a fossil fuel because it is formed from the remains of plants that are up to 400million years old. Over this vast period layers of plant matter formed one on top of the other and were compressed by the covering water and soil. As air was then limited to these layers the full decomposition process was halted. The subsequent heat and pressure produced chemical changes in the plant layers, forcing the oxygen out and leaving rich carbon deposits behind. The resulting solid material became known as coal, and was found in the seams of the earth. The carbon is generally considered to be the most important part of this process, as it gives the coal most of its energy.

How does it burn?

Due to the composition of coal, it is an ideal fuel to burn due to its burning temperature and qualities. When burned, coal generally burns with a yellow smoky flame and leaves ash behind. The energy produced by the coal depends on its type, e.g. bituminous coal is a powerful fuel.

How long has coal been used?

The earliest reference of coal can be traced by to ancient Greece, in approximately 317-287 BC. Although coal was sporadically used in the centuries following this, it wasn’t until the Industrial Revolution in the 18th Century that coal became commonly used across the world. This was partly due to advancements in mining techniques and the need for a strong fuel to power steam engines and steamships.

Between the 1800s and 1950s coal was the primary energy source for industry and transportation. Although alternative energy sources such as gas have risen in popularity, coal remains an important fuel source to provide heating and hot water to a large number of people across the world.

How do we get coal?

Coal is mined from the ground, either underground by shaft mining through the seams or in open pits.

The majority of coal is too deep and requires underground mining. This makes up around 60% of the world coal production.

Coal is mined commercially in over 50 countries, and has grown fastest in Asia over recent years. The top three countries for mining coal (due to the total produced) are China, the USA and India.


Are there different types of coal?

There are a number of different types of coal, each with varying burning qualities. The type of coal depends on the original plant material and its infusion with carbon. Generally speaking, the older the coal, the higher the carbon content.

-          Lignite coal

As a young type of coal, Lignite has a brownish colour and a high moisture content of up to 45%. Lignite is not as dense as other types of coal and can break up when exposed to the weather. Lignite is commonly referred to as brown coal.

-          Sub-bituminous coal

Also known as black lignite. This type of coal contains 20-30% moisture and can be used for heating or generating electricity.

-          Bituminous coal

A soft, dense and black coal. Bituminous coal is the most common coal and has a moisture content of less than 20%. This type of coal is usually used for generating electricity and heating in the home.

-          Anthracite coal

Also known as hard coal, this type of coal is hard and black. Anthracite is high in carbon and low in sulphur, with a moisture content of less than 15%.  Anthracite is a naturally occurring smokeless fuel and is used in solid fuel cookers and boilers.

How does one type of coal differ from another?

Coal is classified according to the following:

  • Energy value – how much is released when burned
  • The carbonisation of the original plant material
  • The moisture content
  • The composition, as it may contain varying amounts of oxygen, hydrogen and sulphur

What is manufactured coal?

The raw coal materials are often blended together to make a better performing fuel. Through carefully adding the right amount of each material we can create coals that burn longer, produce less smoke, less CO2 emissions and give off an attractive flame. For instance, a manufactured coal such as Homefire would contain anthracite to make it smokeless and house coal to make it easier to light. This is all bound together using an agent such as molasses – which is a renewable energy source.

At CPL we produce a number of manufactured fuels which combine different high quality characteristics to make your favourite coals.

Are there eco-friendly coals?

Although coal is traditionally considered to be harmful to the environment, over recent years there have been radical developments within the manufacturing process to improve the CO2 emissions of coal.

Through carefully blending together different raw materials we have managed to create more eco-friendly fuels such as Ecoal50, which contains 50% renewable materials without losing any of the performance associated with quality coal. By increasing the renewable energy involved, this coal emits 25% less CO2 than ordinary house coal into the atmosphere.

Going forward, there is continual testing of new coal combinations to try and produce coal that is even better for the environment.

Are there still coal pits in the UK?

There are a number of working pits still operating in the UK, although the amount has dramatically dwindled over the past 30 years. There are no deep mines still open, but there remain some large scale open cast mines and some small privately run mines.

The remainder of the coal is imported by high producing countries like Colombia, Russia, or Poland.

What is the best type of coal?

This is completely subjective and depends on the type of fuel you desire. For instance, if you are looking for a coal that combines eco-friendly qualities with high performance, than Ecoal50 would be the right one for you. In terms of performance, our Homefire range is high quality and creates a stunning heat output.

One of the factors you must consider is the quality of the coal against the initial price. People instinctively look to the cheapest product but this is usually not the most cost effective choice. Premium fuels, such as Homefire, have greater heating efficiency than ordinary house coal and therefore produce a stronger fire with a longer burning time. Burning a premium smokeless coal over the course of a year will save you money against burning ordinary house coal.