Saturday, 27 August 2011
Electricity GenerationEighty-two percent of Kentucky's coal is used to generate electricity. After coal is mined, it is transported to power plants by trains, barges, and trucks. A conveyor belt carries the coal to a pulverizer, where it is ground to the fineness of talcum powder. The powdered coal is then blown into a combustion chamber of a boiler, where it is burned at around 1,400ºC. Surrounding the walls of the boiler room are pipes filled with water. Because of the intense heat, the water vaporizes into superheated high-pressure steam. The steam passes through a turbine (which is similar to a large propeller) connected to a generator. The incoming steam causes the turbine to rotate at high speeds, creating a magnetic field inside wound wire coils in the generator. This pushes an electric current through the wire coils out of the power plant through transmission lines. After the steam passes through the turbine chamber, it is cooled down in cooling towers and it again becomes part of the water/steam cycle.