Working On-Grid Solar PV System:
Once solar generation starts, the generated energy is first consumed by the loads. Once the load requirement is satisfied, the remaining energy will be exported to the grid. Grid by itself acts as a virtual battery taking in all the excess energy that has been exported. This is known as the banking of energy.
During the night, when there is no solar, the loads can import the banked energy. Similarly, when there is less generation from solar due to cloudy conditions, the required energy is imported from the grid. At the end of every billing cycle, the export and import billing will be calculated and this net will be calculated with the help of a Bi-directional meter.