I’m a little wary of plug-in solar in the US. Some of the bills propose allowing 1200 watt panels which can overload wiring depending on what else is on the circuit and how in the wall wiring is run. Limiting plug-in panel wattage to, say, 400 watts might be necessary
The plug in systems aren’t meant to provide power on their own, they’re meant to supplement grid power and reduce energy costs for the purchaser. They don’t provide electricity unless some is already detected on the line, for the exact reason you ask