Electric power systems are comprised of components that produce electrical energy and transmit this energy to consumers. A modern electric power system has mainly six main components:

1) power plants which generate electric power,

2) transformers which raise or lower the voltages as needed,

3) transmission lines to carry power,

4) substations at which the voltage is stepped down for carrying power over the distribution lines,

5) distribution lines, and

6) distribution transformers which lower the voltage to the level needed for the consumer equipment. The production and transmission of electricity is relatively efficient and inexpensive, although unlike other forms of energy, electricity is not easily stored, and thus, must be produced based on the demand.