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The word "electric" comes from the Greek word "amber". Electricity is an apparent force in nature that exists whenever there is a net electrical charge between any two objects. Electricity is a form of energy produced by the movement of electrons. There are two kinds of electricity: static electricity and current electricity.
Static electricity stays in one place and doesn't move like current electricity. Lightning is the most spectacular example of static electricity. This is a huge spark that flows between positive charges in the top of a thunder cloud and negative charges in the bottom.
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Current electricity is the flow of electric charge through a substance that conducts electricity. Volts, amps, and watts measure electricity. Volts measure the "pressure" under which electricity flows. Amps measure the amount of electric current. Watts measure the amount of work done by a certain amount of current at a certain pressure or voltage.
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• Current is a measure of the rate of electron flow through a material. Electrical current is measured in units of amperes or "amps" for short. This flow of electrical current develops when electrons are forced from one atom to another.
• Ampere - a measure of current -One amp is defined as 6.28 x 10 18 electrons per second.
• Volt - the rate at which electricity is moving
• Watt - a measure of the power of electricity
• Kilowatt-hour - a measure of electric energy
Electrical power is usually measured in watt (W), kilowatt (kW), megawatt (MW)
US Electricity Production By Source
Coal 53%
Gas 16%
Nuclear 21%
Hydro 7%
Oil 2%
Other 1%
Total 100.0
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Conventional electricity sources include coal, nuclear, oil, natural gas, and large hydropower facilities. These sources supply about 99% of the electricity used in the United States today.
In a power plant, electricity is produced by generators, which are driven by turbines. Turbines may be powered by water, as in a hydroelectric plant, by wind, or by steam, as in a nuclear or fossil fuel plant.
California Energy Commission Graphic
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• Boiler
The boiler in a power plant has two basic functions: to burn fuel to produce heat and to use the heat to turn water into steam. Fuel enters the boiler's furnace and is ignited, producing heat. Inside the walls of the boiler are long, vertical tubes that contain water. As the temperature inside the boiler increases, the water begins to boil, forming tiny steam bubbles. The steam rises to the top of the boiler to a steam collection drum. From there, the steam travels through pipes to the turbine.
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• Turbine
The turbine transforms the thermal energy in the steam into mechanical energy. It provides the mechanical motion necessary for the generator to do its job. A turbine is constructed of a long shaft to which a series of blades are attached. This is called the rotor. As steam enters the turbine, it is directed through the sets of blades. The force of the steam against the blades causes the rotor to spin. It is similar to blowing on a pinwheel, but much faster. Steam turbines spin at 3,600 revolutions per minute (60 cycles per second or 60 Hz).
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• Generator
The generator is directly connected to the turbine, so when the turbine spins, the generator also spins. It transforms the mechanical energy (provided by the spinning turbine) into electrical energy. Electricity is produced by rotating a conductor through a magnetic field or by rotating a magnetic field around the conductor. Each time the conductor travels, or cuts, through the magnetic field, a voltage is created (induced). After leaving the generator, the electricity travels to the plant's substation where transformers are located. The transformer increases the voltage of the electricity so it can travel through the distribution lines efficiently. Then, in local areas, the electricity travels to another substation where transformers reduce the voltage again for consumer use. All this happens at the speed of light.
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