Coal

The basics of Coal

Coal has historically been a very important source of energy. Archaeological records indicate that people burned coal over 4,000 years ago in Wales. Although it has recently been gradually displaced by natural gas in some parts of the world, most notably in Europe, coal continues to dominate many national fuel markets in developing Asia, and its global consumption is projected to keep increasing in the mid-term.

With rapid improvement in emissions reduction technology, better environmental management in mining operations, widespread availability world-wide, and substantial remaining reserves, coal will continue to play a vital role in providing the world's energy well into the foreseeable future.

Types of Coal

Coal is a fossil fuel formed by the decay of plants that lived millions of years ago. It is a much more heterogeneous source of energy than is oil or natural gas, and its quality varies significantly from one region to the next and even within an individual coal seam. Depending on the degree of transformation of the original plant material to carbon, coal comes in different forms and qualities. These types of coal are ranked from those with the least carbon content, to those with the most carbon:

- Lignite (18% of world production in 2001): is a soft, brown or black form of coal, that can be found on or near the surface of the earth. Although it will burn, the flame is smoky because of the moisture content. Lignite is not traded to any significant extent in world markets, because of its relatively low heat content.

- Sub-bituminous: harder than lignite but softer than bituminous, it contains more moisture than bituminous, which makes it less economic to transport over long distances.

- Bituminous: is the most abundant type of coal. It has lost most of its moisture and nitrogen impurities. Bituminous coal can be metallurgical -- used to make coke for the steel industry -- and is also an efficient heating material.

- Anthracite: is found only in areas where tremendous pressure and heat from mountain building processes can change bituminous coal into a hard substance which is mostly carbon. Anthracite is the cleanest of all coal, since it has the least impurities.

Two larger categories are often used to simplify these different types of coal: steam coal and coking coal. Coking coal by definition is a hard coal, i.e. anthracite or bituminous coal, which allows production of coke for blast furnace production of pig iron and/or for heating. Other coal is marked as steam coal, because it is suitable for use under steam boilers (electricity generation).

Use

Coal is mostly used (55%) in electricity generation, and significant amounts are also used in steel production (14%), with two thirds of steel production depending on coal. (Source: World Coal Institute).

Coal represented 23.3% of the world primary energy consumption in 2001, a share that goes up to 38.7% for electricity generation. Some countries depend more heavily than others on coal for electricity generation. Among them are Poland (95%), South Africa (93%), India (78%), Australia (77%) and China (76%). (Source: World Coal Institute).

The growth in coal use in the next decade will be supported mainly by electricity production, whereas the industrial sector is increasingly switching to cleaner and more efficient technologies.