One way I have thought about an off-grid system, is to have the A/C connected to the solar, and everything else using PEA. This allows the most energy consuming device to be off the grid. When you have a brownout or blackout, have the whole house set up to be switched over to solar until such time the PEA is running again. When the mains drop out, you would have sensitive devices on a small individual UPS's, they would protect them from brownouts as well, which are much more damaging. Switching everything over to solar, would of course, allow life to go on. Switching could be automatic, or manually, using a large amperage industrial disconnect, relatively inexpensive and would last decades. I believe the above described system would allow solar to be used without interfering with the PEA, as it is totally independent. Getting deep into it, possibly programming a good PLC to detect a phase loss and energize a large contact, doing the switching automatically. I am open to suggestions, as I am a lowly Industrial mechanic and not an engineer. ????