I don't have enough real estate for a solar system that would be close to break even, but have looked at the feasibility of a generator/battery/inverter system that I could use with our small camper. Even for a tiny system like I'd need (3 KW 120V single phase if I run the air conditioner or microwave) a safe inverter is way out of my tolerable price range¹, and that's dirt cheap compared to the 20 - 30 KW(+?) 220 V 2-phase capacity you'd need in order even to think about trading power with the utility guys here.

¹ batteries not included, of course.

John