On grid systems are the most common type of solar PV system. Grid-tied systems are connected to the electrical grid, and this allows residents of a building to use solar energy as well as electricity from the grid. Grid-tied systems do not need to produce 100% of the electricity demand for a home or business. When a home or business is using energy, but the solar panels aren’t producing enough energy (at night, or on a stormy day), electricity from the grid supplements or replaces electricity from the panels. Living with a grid-tied solar PV system is no different than living with utility electricity, except that some or all of the electricity you use comes from the sun.