A grid-tied solar power system, also known as a "grid-connected" or "utility-interactive" solar power system, is a type of solar power system that is connected to the electric grid. These systems generate electricity from the sun, provide it directly to the home, and feed extra power back into the grid. This configuration allows the homeowner or business to use the power they generate, as well as draw power from the grid when necessary.
Grid-tie systems allow the homeowner or business to reduce their dependence on the utility company, while still having access to electricity when the solar panels are not generating enough power. These basic, grid-interactive solar power systems are cost-effective, easy to install and maintain, and do not require batteries (though batteries can be added to enable backup power).
Since a grid-tied solar power system is connected to the electrical grid this type of system requires an interconnection agreement with the utility company and a bi-directional meter to be installed to measure the power going to and from the grid. It's important to note that if a grid-tied solar power system does not include energy storage, there is no backup power in case of a grid outage. Solar power systems must be interconnected with the grid or a battery power supply in order to operate.
The primary purpose of a grid-tied system is to offset the building's use of power from the grid and to reduce power bills. For the best results, the system should be sized to match the average daytime energy use, and strategies can be used to maximize solar power consumption by running appliances during the day when the sun is shining.