Coal as an important energy source
Coal is a combustible geological sedimentary rock, composed mainly of carbon and hydrocarbons. It is the most important source of energy for generating electricity worldwide and is the single largest source of energy used to produce electricity (accounting for 40% of global electricity generation). Coal has been used for centuries as a primary source of energy, principally for the purpose of heating homes and businesses. In the last two centuries, coal has become one of the most important sources of energy in industrialised countries, with more than half of global electricity generated from coal.
Coal is mainly composed of carbon, but it also contains other elements such as sulfur, nitrogen, oxygen, and hydrogen. Its composition varies according to the place and time from which it has been extracted, with some coals being hard and dense while others being softer and more brittle.
The use of coal as an energy source has brought many benefits to our society. Countries that rely heavily on coal for energy are enjoying a lower cost of electricity than those who rely on other energy sources. This advantage applies to both developed and developing countries which are customers of coal-fired electricity.
In addition, coal is a secure and reliable form of energy, with the majority of coal reserves located within reasonable transport distance of where it is needed. This has enabled countries to access secure and affordable supplies of energy without having to worry about supply disruptions from far away locations.
The environmental impact of coal as an energy source has become a major focus of debate in recent years. While it remains a key component of the global energy mix, it also has the potential to cause significant environmental damage if not managed responsibly. A key environmental concern is the production of greenhouse gases such as carbon dioxide (CO2) and sulfur dioxide (SO2). Burning coal produces large amounts of CO2, which is one of the main contributors to the global rise in temperatures. The emission of SO2 is a major source of air pollution.
In addition, the extraction and use of coal can cause water to become polluted with heavy metals such as lead, mercury and arsenic which can cause serious health risks if ingested.
The increased production of coal has led to advances in clean coal technology, which seeks to reduce the environmental impacts of coal while still retaining its benefits as an energy source. Clean coal technology includes methods such as reburning, chemical looping and integrated gasification combined cycle (IGCC). Reburning involves burning the coal in such a way that the emissions from the coal-burning process are absorbed by compounds to reduce the emission of pollutants such as SO2. The use of chemical looping involves using a chemical reaction to release the heat from coal and capture the emissions before they are released into the atmosphere. Finally, IGCC is a process that involves using gasification to produce a synthesis gas which is combusted to generate electricity. This process is much cleaner than traditional coal burning, as compared with the IGCC process, emissions of CO2, SO2 and NOx (nitrogen oxides) are drastically reduced.
Despite its drawbacks, coal remains an important source of energy, and will continue to be used for many years to come. While its environmental and health impacts must be addressed to ensure its sustainable use, its availability, reliability and low cost make it an attractive option for countries that need to produce electricity or heat their homes and businesses.
