FEATURE

Power: from Atom to Application: A Six Segment FEATURE

The Science of Electricity         Power Generation        The Transformer        Interconnections         The Flow of Power         The Motion of Electricity        
PLUS
Seven Bullets: The Vulnerability of the Grid         The State of the Electric Grid        
Power Generation

Power Generation


If moving a wire back and forth in a magnetic field creates electricity by moving the electrons in the wire, then moving it really fast will create a lot of electricity. The most ideal way of moving electrons at a high speed is accomplished by using a generator. The basic principle behind it is that by spinning several magnets inside coils of copper, the electrons in the copper will become highly active, stay in motion, and thus stay charged. Rotating the magnets more quickly moves the electrons more quickly and thus creates more of a charge. A rotor in a generator is thus, obviously, referred to as such because it is rotating several magnets inside a fixed series of copper wires. The fixed wires are referred to as the stator as they don’t move. The magnets are known as electro magnets as they are not naturally magnetized. By passing a separate current through them, magnetic fields are created and can be made more powerful, or turned off.
Generators
A mechanical force is required to spin the rotor inside the stator. The simplest application is a wind turbine. When the wind blows, the blade spins. The blade is attached to a rod which is attached to the rotor in a generator. But to create a lot of electricity requires a lot of spinning force. Enter the turbine. Hydroelectric turbines in dams spin when water is passes over the turbine blades which then turn the rotor. In coal and natural gas plants, steam is created by the burning of these fuels. The steam is then forced passed turbine blades which, as with every system, then turn the stator.

A power generator converts the mechanical energy of a turbine into electrical energy. As the magnets in the rotor spin past the copper windings in the stator, electrons are being spun off their atoms in the copper winding as previously described. This movement of electrons creates electricity. As the rotor continues to spin, the electrons down the line of a wire (made of copper or aluminum) are displaced, creating a “flow” of electrons through the wire. It behaves much like a water system. The generator acts as a pump, pushing water (electrons) through the hose (the copper wire). Electric current is a flow of electrons. Turn off the pump (generator) and the water stops. Increasing the speed of the pump thus increases the flow of the water allowing it to travel further down longer lengths of hose. High powered electric generators thus use magnetic force to push more electrons further down the power line and at greater pressures. It’s important to note – the generator is not really creating electricity – it is simply moving the electrons in the wire that already exist there. In essence, the generator is simply pushing the electrical potential that exists in the wires. Generators cause electricity to flow rather than actually creating it.

The water example is provided as an example. But in actuality, the electrons aren’t really flowing… the electricity is flowing. Look at it more in this way. As you yell to a friend across the room, the sound from your vocal chords is not what your friend hears. As your yell vibrates off your vocal chords, the air molecules in front of you begin to vibrate. This vibration travels like a wave across the room where your friend hears it. Similarly, electrons are not actually flowing so much as they are in essence, vibrating – and causing the electrons in the atoms nearby to vibrate. The harder the vibration – or pressure, (voltage) – electrons further down the wire line will be made to vibrate. So, when we talk about flowing electrons, we’re really more talking about flowing electricity. Electrical energy is the wave travelling along the vibrating electrons inside the wires. Generator Stator Rotor