There are a few important terms to grasp to understand how electricity is produced and delivered to homes and businesses:
Generating Stations or power plants are where electricity is produced by utilizing resources such as natural gas, the sun, wind and steam heat from within the earth.
Transmission Lines are the “energy superhighways” of an electric system, carrying large amounts of electricity from power plants over long distances and at very high voltages – typically 69,000 to 500,000 volts. SDG&E has over 1,800 miles of transmission lines in its service territory, but only has two connections to the state’s electric grid.
Substations are specialized equipment to reduce or “step down” transmission line voltage and connect high voltage transmission lines to lower voltage distribution lines. SDG&E currently operates more than 200 substations.
Distribution Lines are the “local streets” that deliver electricity directly to homes and businesses. SDG&E operates over 15,000 miles of distribution lines.