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A Coal-Fired Thermoelectric Power Plant
Georgia Power's Plant Scherer
Georgia Power's Plant Scherer is one of the largest coal-fired thermoelectric power-production facilities in the United States. It is a 3,520,000-kilowatt coal-fired facility that provides electricity for Georgia. As this diagram shows, the plant operates on the same principles as other fossil-fueled electric generating plants—it burns coal to produce heat that turns water into steam, which then turns turbines in a generator.
A large thermoelectric plant like this burns a lot of coal—in this case, about 11 million tons per year. Coal that has been ground into a fine powder by a pulverizer is blown into a furnace-like device, called a boiler, and burned. The heat produced converts water, which runs through a series of pipes in the boiler, to steam. The high-pressure steam turns the blades of a turbine, which is connected by a shaft to a generator. The generator spins and produces electricity.
In the diagram you can see how the main use of water is to cool the condenser units, which receives the condensed steam that was used to turn the turbines. The hot, condensed steam water is run through pipes that are cooled by the cooler water (withdrawn from the Ocmulgee River and Lake Juliette reservoir in this case). The condensed water is thus cooled down and then recirculated back through the coal-fired boiler to again turn to steam and power the turbines. This is the closed-cycle loop part of the system and it reuses the water continuously.
In the other part of the water-use cycle of the plant, the open-loop cycle, massive amounts of water are taken from a river and reservoir and is pumped to the condensers. This cooler water surrounds the pipes containing the hot condensed steam and thus is heated up a lot. The hot water is pumped from the condenser units into the four 530-foot tall cooling towers so it can lose its heat. Each cooling tower at Plant Scherer circulates 268,000 gallons of water per minute. Most of this water is reused after it cools, but about 8,000 gallons per minute are lost to evaporation (thus you see the steam escaping from the tops of the cooling towers).
Source: Plant Robert W. Scherer, Georgia Power (PDF)