Grid-Tied Systems are connected to the electrical grid by allowing the resident of a building to use solar energy as well as electricity from the grid. These systems do not need to produce 100% of the electricity demand for a home or business under the Net Metering System. When there is no demand for energy, the solar panels send excess electricity back out into the grid. When a home or business is using energy, but the solar panels are not producing enough energy (at night or on a stormy day), electricity from the grid supplements or replaces electricity from the panels. Hence, the excess units (if any) will be carried forward to the following month’s bill as a credit. Only outstandings to the grid will have to be settled by the customer.