Trying to get a number from the city, but they're in a zoning revamp right now and I gave up trying to find someone who will give me a straight answer. I figure what they don't know won't hurt them, and it wouldn't be more than twenty or thirty gallons anyway. How much exactly is entirely dependent on energy rationing strategies and I'm still mulling those over.
Giving some thought to a hybrid solution... a generator to power the panel combined with a battery-based power unit for fridge and freezer. Something like the Jackery Explorer 1000 or similar. That would give 24/7 power for food storage, firing up the the generator only enough to recharge the power unit or to supply as-needed supplemental power. Using typical demand estimators and a couple of in-use reviews, I figure the 1000 would probably give us a rolling 12 hr schedule (4-6 hrs on battery and 6-8 on generator). The power unit would be handy for day-to-day uses, too. At only 22lbs and relatively small, I can think of a whole host of uses for it. Only downside is price. It's a spendy little sucker.
The probability of losing power more than 48 hours is very, very low so I'm using three days as my spread, including last-resort contingencies to five days in case we're unable to relocate (extremely unlikely for multiple reasons, at least in the context of most-probable scenarios).
This will be set up as a stop-gap, a short term solution. If it's going to be more than that, we have friends and family spread all over Texas, eastern New Mexico, and southern Oklahoma. Plenty of alternate locations. If it comes to it, we'll mothball the house and head to more hospitable environs.
Brad