by Earl King

Created on: May 09, 2008   Last Updated: May 12, 2008

HOW WE GET ELECTRIC POWER

Energy is all around us. It is part of our environment. Without it the universe would come to a standstill. Another major part of our environment is matter. Matter is anything you can see and touch. The work of Albert Einstein has shown that matter and energy are equivalent. We can change matter into energy.

Energy is found in many forms. Some of these are heat energy, potential energy, chemical energy or mechanical energy. Chemical energy is one way of providing power or current from batteries. The other forms must be converted into mechanical energy before they can be changed to electrical energy.

Heat energy can be produced from the splitting of atoms. It can also be produced by burning. Material such as wood, coal, oil or gas may be burned to release their energy and we can use it raise the temperature of water. Apply enough heat and we get steam. This steam and the pressure it can create may be used to turn machines called turbines. The turbines will then turn other machines called generators. It is in this last machine that the mechanical energy is converted to electricity.

Another form of energy called potential energy, is found when anything is located above the earth. An example is a lake held back by a dam in such a way that the water may be funneled down through tubes to a lower level than the lake. The falling water, acting under the force of gravity, is diverted onto the blades of a turbine where the potential energy of the water is converted into mechanical energy. The turbine then turns a generator. This power source is called hydroelectric.

In order to be of use in a typical power system, the amount of power produced must be large. Energy losses found in every part of a system can represent a sizable amount of power. To be economical, a great number of customers must be served. We must generate a lot of power to provide for these losses and for whatever customers may be attached to the system. To give you an example of what we are talking about lets get a handle on measurements and quantities.

Voltage is electrical pressure. Think of voltage as compared to water pressure. The water pressure pushes the water (current) along a pipe (conductor), as the voltage "pushes" electric current down a wire (conductor). Electric current is expressed in amperes which is the rate of flow of electricity.

Power, the rate at which work is done, is expressed for an automobile engine in horsepower. For electric power it is expressed

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