The following diagram illustrates the components typically required in a grid connected PV system. A grid connect PV system is connected to the local electricity network. This means that during the day, the electricity generated by the PV system is fi rst used internally within the building and any excess is exported from the building. At night, when the solar system is unable to provide the electricity required, or if the load during the day exceeds generation, power can be bought back from the network and used in parallel with the PV to provide electricity. In eff ect, the grid is acting as an energy storage system, which means the PV system does not need to include battery storage.