Any electricians in the house?

Theo said
Feasible, I have a gridtie system, and also regularly backfeed using a generator when my local utility goes down - but never both at the same time. I take great care to isolate from the utility mains AND my solar system before I do it (I'm a retired EE with some common sense)

Where do you think the excess power from your solar system is going to go if you're isolated from the main and using your generator at the same time to sync it ?????

Better read this article:
https://www.payperwatt.com/post/can-grid-tied-inverter-operate-in-parallel-with-diesel-generator

Nice !

IMHO, batteries are the key to solar. Many power companies are going to Time Of Use billing. So they will be paying less for power fed back to grid when it’s less needed (during middle of day when everyone has peak solar) .

Then you can save the power in your battery and use it at night to charge your car(s). When the rate is higher. Or sell it back to utility at a higher $ rate.