

Not just solar - most grid-scale generators have this problem. “Black start” is the search term you want to look for, and Practical Engineering has a good video on the subject.
Basically, only a relative few grid generators are actually capable of black starts. The rest need the grid to be already functioning before they can tie in and start producing.






The UK uses single phase to the house. This is provided via one 240v hot and a neutral. Their final distribution transformer bonds one side of the output coil to ground and use it as a neutral, which makes the other side of the coil 240v relative to that ground.
The US uses split phase to the house. This is 240v provided via two opposing 120v hots and a common neutral. Their final distribution transformer is almost identical to the UK version: end to end, they have a 240v output. The difference is that instead of bonding one end of the output coil to ground and using it as a neutral for the other end, they instead bond the center of the output coil to ground and use that as a common neutral for both ends.