[philb]

Instead of putting in separate plugs, just split the circuits you want to power at the breaker box. Any electrician should be able to do that. That way you've saved a lot of expensive copper wire. You can use a transfer switch like this one.

There are many ways you could do this. Grid tie PV is probably the easiest way to go.

I have a separate system with solar panels, charge controller, inverter and the transfer switch because I don't want to deal with the electric company and their rules and regs. They will allow me to put electricity into the grid until my bill equals zero. Any electricity in excess, they won't pay me for it. I said no thanks!
You can also get 30% of the system costs on your federal taxes. Texas also has some incentives.

As soon as I learn how to post, I have a story about my system.