How is electricity generated using coal?

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txmedteach's profile pic

txmedteach | High School Teacher | (Level 3) Associate Educator

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Coal power is based on the same concept that many methods of producing power use. Basically, the goal is to heat water into steam, which then increases in pressure as it is further heated. As the steam's pressure increases, it starts to flow into a turbine, causing the turbine to spin. The turbine then spins a magnet or conductor to induce a current and create electric power.

The difference between coal power and other forms of power its method of heating. The cost for coal is very cheap, but the environmental impact is very high. However, for our discussion, let's consider the difference in terms of heating water to spin the steam turbine. Coal, or its derivative coke, is heated to the point of combustion. The combustion of coal is exothermic, meaning the process releases heat. This heat is then transmitted to other coal to keep the fire burning, or it is transmitted to the water to create steam to spin the turbine.

Coal power is still the primary source of power in America due to its relatively low cost. However, coal power has been implicated in pollution and global warming. Hopefully, in the future, other fuels can be used, or inexhaustible resources can be tapped for energy. However, for now, research has made coal one of the most heat- and cost-efficient forms of energy available, and it's likely to stay around for some time.

I hope this helps!


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najm1947's profile pic

najm1947 | Elementary School Teacher | (Level 1) Valedictorian

Posted on

Coal is fossilised carbon. When it burns in air, it realese thermal energy in the exothermic reaction converting in to corbon dioxide using oxygen present in the air. The heat energy is passed on to the air/carbondixide mixture (Flue gases).

This heat energy is used in a boiler to raise steam at very high temperature and pressure. Boiler is a pressure vessel which is used to heat water for making steam. Heat from the coal in form of radiation and from flue gases is passed on to the water through the urnace and pipes of the boiler. In this process water absorbs the heat energy to rise it temperature and for conversion in to steam at very high temperature and pressure.

This steam is passed through a steam turbine at very high speed. Turbine is a machine which converts the energy of steam in to mechanical energy by spinning its rotor at very high speed. In this passage through turbine, steam expands, cools and reduces its speed and releases its energy. This energy is passed on to the turbine rotor and is converted in to mechanical energy of the rotating turbine.

Turbine is coupled (connected) with a genertor, an electrical machine which converts the mechanical energy in to electrical energy. In a generator, coils of copper wires rotate through a magnetic field and electricity is induced in the copper coils at a very high voltage. This is how electricity is produced using coal in a power station.

The whole process can be shown as under:

Coal+Air (Heat energy) => Water/Steam (Heat energy) => Turbine (Mechanical Energy) => Generator (Electrical Energy)