[sumtechguy]

Having just put a battery into my existing system. For the power company I use the answer is no to your question. Many power companies charge that fee depending on the size of panels. Now if you do not hook to their system they do not care (off grid). But if you plug into it then they care and charge for the privilege.

Now you could pull particular items out of their grid. Just need the wires and panels to make sense. They would not care about that either. It is only if the panels are plugged into the grid they start to care. Downside is sometimes waiting for that battery to have enough juice to work. It goes faster than you think and some battery systems are decently expensive just by themselves, on top of the panels/inverters/controllers/install.

[inigyou]

In that kind of situation you could work around this legally just by reconnecting loads to the other system as needed. E.g. battery is getting low, better unplug the fridge from the green-painted solar power outlet and plug it into the red-painted grid power outlet right next to it. You maintain the air-gap but still get to load-balance.