Enable grid-tied solar array power output during grid outage
The main issue is that most grid tie inverters are not designed for standalone operation, they are designed to always pull the maximum amount of power possible from the panel. That way it always harvests the maximum possible amount of energy each day giving you the maximum possible savings (assuming you get paid for feeding power back to the grid). Standalone operation is different as the inverter will need to regulate its output so it pumps out only as much energy as you need, otherwise it'd overload something. There are grid tie inverters that work in standalone operation as well but they cost more (smaller market share, economies of scale etc.) Unkess it explicitly states both standalone and grid tie operation, assume it only does one or the other (there are plenty of standalone only inverters too so be careful)