World energy consumption is growing. Reliable forecasts say total energy consumption will increase by around 35–40% in the next 20 years, and coal will still be the major source of power generation globally.
According the International Energy Agency, in 30 years’ time the volume of the international coal trade will increase by almost 1.5 times compared to current levels and trade flows will continue to move towards Asia. Continuous improvement in geological exploration and mining methods mean new coal resources continue to be found.
Currently most conventional coal-fired power plants operate under sub-critical steam conditions, with a maximum efficiency of about 39%. New supercritical coal-powered plants can achieve efficiency above 40%, whilst ultra-supercritical plants can potentially boost efficiency to 50% or more. Globally 64% of coal power plants under construction now are supercritical or ultra-supercritical.
With growing concerns over sustainability of the global power supply, the coal industry constantly works on improving all aspects of its activities.
A one percentage point improvement in the efficiency of a conventional pulverised coal combustion plant results in a 2-3% reduction in CO2 emissions.
Advanced cleaning and firing systems on coal-fired power plants have already helped to reduce the output of sulphur dioxide (SO2), nitrogen oxides (NOx), complex hydrocarbons, dust and heavy metals.
Increased coal washing lowers ash content by more than 50% by removing extraneous rock and high ash coal, which means less waste is transported and less ash is disposed while the coal provides greater thermal efficiency.
During underground mining, highly concentrated methane (CH4) can be captured and removed by extraction systems. Where practical, this gas is used to generate electricity or to heat mining facilities. Otherwise, it can be safely burned rather than discharged into the atmosphere. The result is reduced greenhouse gas emissions per tonne mined.