What Is a Grid-Tied System?

Power flows both ways at the meter. By day the system feeds the home first, and any surplus goes out to the grid. At night or on dark days the home pulls from the grid as it always has. The inverter stays synchronized to the grid’s signal and is built to stop quickly when that signal disappears, a protection called anti-islanding. That behavior keeps a house from energizing lines that repair crews believe are dead.

Almost all residential solar is grid-tied, so the term mostly shows up as a contrast with off-grid systems and as an expectation problem. Homeowners assume solar means independence from the utility and from outages. A grid-tied system still produces a bill, still depends on rate rules for how exports are credited, and goes dark in a blackout unless the design adds a battery and backup equipment. Closers should say so before a signature, not after the first storm.

Off-grid and hybrid get lumped in. Off-grid systems have no utility connection and must carry their own storage and often a generator, which makes them rare for homes with grid access. Hybrid systems stay connected and add batteries. The grid connection also brings paperwork, since the utility has to approve the interconnection before the system can run, which is why panels on a roof are not producing power on day one.