For example, here in Atlanta, Georgia at 5:00 PM on a hot August weekend day, you can bet there is a huge demand for electricity to run millions of air conditioners! But, 12 hours later at 5:00 AM. Demand goes up and down during the day, and overnight there is less need for electricity in homes, businesses, and other facilities. Pumped storage: Reusing water for peak electricity demandĭemand for electricity is not "flat" and constant.
This, in turn, causes electricity to flow and a voltage to develop at the generator output terminals." When the rotor turns, it causes the field poles (the electromagnets) to move past the conductors mounted in the stator.
The rotor is attached to the turbine shaft, and rotates at a fixed speed. These are called field poles, and are mounted on the perimeter of the rotor. In a large generator, electromagnets are made by circulating direct current through loops of wire wound around stacks of magnetic steel laminations. He found that when a magnet is moved past a conductor, it causes electricity to flow. The operation of a generator is based on the principles discovered by Faraday. A hydroelectric generator converts this mechanical energy into electricity. "A hydraulic turbine converts the energy of flowing water into mechanical energy. By the way, it is not a good idea to be playing in the water right below a dam when water is released!Ī turbine and generator produce the electricityĭiagram of a hydroelectric turbine and generator.Īs to how this generator works, the Corps of Engineers explains it this way: The water continues past the propellor through the tailrace into the river past the dam. Power lines are connected to the generator that carry electricity to your home and mine. The shaft from the turbine goes up into the generator, which produces the power. At the end of the penstock there is a turbine propellor, which is turned by the moving water. Gravity causes it to fall through the penstock inside the dam. Near the bottom of the dam wall there is the water intake. The dam stores lots of water behind it in the reservoir.
The theory is to build a dam on a large river that has a large drop in elevation (there are not many hydroelectric plants in Kansas or Florida). Take a look at this diagram (courtesy of the Tennessee Valley Authority) of a hydroelectric power plant to see the details: A coal-fired power plant uses steam to turn the turbine blades whereas a hydroelectric plant uses falling water to turn the turbine. In both cases a power source is used to turn a propeller-like piece called a turbine, which then turns a metal shaft in an electric generator, which is the motor that produces electricity. So just how do we get electricity from water? Actually, hydroelectric and coal-fired power plants produce electricity in a similar way. Falling water produces hydroelectric power.