Thermal coal, also known as steam coal is used for power and heat generation. In electricity generation, thermal coal is ground to a powder and fired into a boiler to produce heat, which in turn converts water into steam. The steam powers a turbine coupled to an alternator, which generates electricity for the power grid. The steam cools down as it turns the turbine generator and is condensed back to pure water, and the proces repeats. In modern coal plants, the steam is kept at extreme temperatures and pressures at all times to increase the efficiency of the power plant.
Around 40 per cent of electric power worldwide is generated using coal. In the Czech Republic approximately 52 per cent of electricity is generated from coal whilst Poland generates around 90 per cent of its electricity from coal.
To generate heat, steam can either be distributed directly to homes and offices from the heating plant or as in modern plants Combined Heat and Power technology is used, which is considered more efficient.
Thermal coal is also used in the cement-making process (calcination).
Coal middlings are a lower quality coal product separated in the second phase of coal preparation based on the specific density of coal.