Once the energy is generated, high-voltage transmission lines carry it to the ultimate consumer. To accomplish this, the energy's voltage is raised to a level that is most efficient to transport large amounts of energy over long distances. Transmission lines are most often supported on poles (wood, cement or steel) along city streets. Together, the transmission lines and their support structures form a cross-country grid that serves as a superhighway for electrical energy.

"Step-down" transformers located in distribution substations, and smaller distribution pole-type transformers reduce the high-voltage energy to a level at which it is safe and practical to connect the energy to homes and businesses. Distribution lines carry lower-voltage electricity from substations to customer areas.

Near each customer’s home or business, the voltage is again reduced by means of a transformer located on a pole or, in the case of an underground area, a pad next to a street. This provides the customer with the right voltage to operate a given piece of equipment such as an air conditioner, an electric range or an electric light. Higher voltage is required for factories using a lot of power and/or high-tech equipment; lower voltage for homes using less power. Voltage is carefully measured to meet the customer's needs.

Priority lines also connect directly to emergency services like hospitals, fire stations and police stations.

Progress Energy's transmission lines, rated at 69 kilovolts (kV) to 500 kV, extend throughout our service territories in the Carolinas and Florida. They also connect our utilities with surrounding electric utilities to promote greater reliability of the regional grid system.

Diagram illustrates the major components of the system used to deliver electricity to homes and businesses from left to right (1) generation sources (power plants) and (2) transmission lines, (3) the transmission-to-distribution substation (where voltage is lowered), (4) distribution feeder (which might serve some facilities directly), (5) power pole (showing underground services to hospital), (6) fuse (designated by 'S'), (7) tap line (the type of line that runs along the streets of neighborhoods), (8) pole-top or pad-mount transformer (for reducing service voltage to individual households and businesses, and (9) service lines to individual homes.