Grid-connected PV systems operate in parallel with your local utility service, providing a supplemental source of clean, renewable energy. Direct current (DC) power from the solar modules is feed to an inverter that converts this energy to utility-grade alternating current (AC). This energy is then feed into a building`s load center, helping offet incomng utility power. These systems can be designed with storage batteries and a special "bi-modal" inverter to act as a back-up power source if utility power fails.

Off-grid PV systems are designed as the primary power source for remote locations without utility service. These systems always have deep-cycle storage batteries and often are coupled with a fossil-fuel generator to provide reliable service regardless of weather conditions. These are called hybrid power systems.