The burning of coal is the most polluting method for producing electricity and the environmental impacts are considerable. Besides the production of greenhouse gases by burning coal, there are also many other harmful compounds released during this process. But environmental problems are not limited to the burning process. The extraction, transportation, storage and disposal of coal all create additional environmental issues.
There is however differences in the amount of pollution caused by burning coal depending on the type of technology utilised. New coal-fired power station technology is emerging with the ability to reduce the amount of greenhouse gases and other harmful compounds released during the burning process. Integrated gasification combined cycle (IGCC) combustion is the realisation of this new technology and claims to significantly reduce harmful emissions. Despite the reductions in pollution from the use of IGCC technology, coal fired power stations will still have serious impacts on the environment.
Without looking at the environmental impacts of mining and transporting coal, the burning process alone results in a host of environmental problems. Air pollution is a major cause of environmental degradation, releasing vast amounts of carbon dioxide leading to increased global warming. Sulphur dioxide and nitrous oxides are released into the atmosphere causing acid rain and lung problems in humans and animals. Smaller amounts of mercury, arsenic and lead are also created and these heavy metals have very serious health implications for all living organisms.
The waste created from the burning process is also very harmful to the environment. The sludge from smoke stack scrubbers is toxic, containing a number of heavy metals that can potentially contaminate the environment. As much of this waste is stored on site at the power plant, it can easily enter the water supply of the surrounding area. The water used to cool the coal burning equipment is often sourced from a local water body and then simply pumped back after it has been used. This hot water, often containing chlorine or other chemicals, can then cause algal blooms and other environmental problems.
Finally, the extraction and transportation of coal to a power plant also has a number of environmental impacts. As coal is predominantly mined from near the surface, many of the ecosystems above are degraded or completely removed. Coal is usually transported by diesel trains over great distances, further releasing carbon dioxide and other harmful compounds. Coal dust is also produced and contributes to particulate matter in the air.