What state, what location?

California, Santa Clara County. But there are other counties, cities and States with bans.

Most of the bans are urban I believe so then off-grid wouldn't be an issue typically. I was born in Santa Clara - and obviously mostly urban/suburban. I can't find any other county with a gas ban despite 80 or so jurisdictions that do. There certainly may be one but I can't find it. There certainly is no state ban. CA is the most aggressive and 2030 is the date and 2028 for generators. And even yours is just 9 months old so little experience for sure.

So the only rural area with a ban today is probably in your area.

Are you at elevation? Because "long winter storms" is really something that most of the county doesn't experience. I just checked - there is no real elevation in the county. On a national forum, you have to imagine that much of the country can't relate to what you mean when you say "winter". Average jan temps for your build would be helpful. Also, I don't remember long stretches of clouds in the winter but your area of the county maybe different. That is an important factor. I just checked my monitor (in NC) and the worst I got in 2022 is a 3 day stretch in Jan when I had a total of 14 kwh of generation. A good Jan day is 30 kwh. You might find someone with a monitor in your immediate vicinity - almost all solar installs have one. Assuming I was designed to use 20 kwh a day - I would need about 50 kwh in batteries. With zero change in behavior. Pretty simple to avoid laundry when it is a really cloudy stretch in Jan.

There was a recent poster here doing off-grid in CA I think. Was able to fall back on propane generators so not exactly the same but at least her plan was a good starting point.

You are right to plan. But it isn't that hard to achieve and understand that you may need or want to vacate every once in awhile. Kind of like you might do for a wildfire or long term blackout if you were on grid. What are you options (ie family nearby)? Because you pay say $20k to be good for 350 days a year. Another $20k for 10 more days. And another $20k for the next 4 days. And then another $20k for the last day.

And keep in mind that V2H is live I believe in Ford products. Tesla has it planned (per hackers who have seen the software.). So once a year, you might have to drive down to town and charge up your car to bring the electrons back home.

V2H ("vehicle to home") is where the car powers the house. A big car/truck can have 100 kwh battery and that can run an all-electric house for days if there was no sun. Because of economies of scale, the battery in a car can be a bit cheaper than a home battery.

People often wildly overestimate the electricity use to heat a well insulated house. I have heat pumps in NC in a modern house. I most likely get colder than you. My 48 panels don't get me off-grid in January - but they could with V2H (if I charged at work in Jan).

Thanks David. I think the "recent poster" you are referring to may have been me. I was planning on propane back-up to my solar until I learned about the gas ban. I will still try to get an exception to the propane tank and generator (although I am planning on V2H as well). I guess I will be breaking new ground both literally and figuratively if I'm the first trying to build off-grid in a gas-banning jurisdiction. Lucky me.

The logical backup power source is the grid. Unless you're going off-grid to avoid monthly service fees.

I'm going off-grid (or at least intending to go off-grid) because my property doesn't have grid and it would cost ~$1/2 million to connect. I don't think PG&E is going to volunteer to run lines to my property and the area requires underground lines so that ups the cost.

Not that it is ideal to plan for but there is no ban on generators yet that I know of. The on-line press releases just mention natural gas and just using electricity for the end result - space heating etc.

I suspect you found about propane more directly. But either way, they aren't likely able to block a portable diesel generator. They are available to be sold in CA until 2028 from what I can tell. They also sell portable propane generators but the county could ban propane tanks above a certain size.

Looks like a gallon of propane will net you about 9 kwh. Amazon will sell you a portable 100 pound tank which is around 20 gallons (I am finding varying numbers but right about 20). The tanks are $450 a piece (less in quantity from different sellers) so you could have 5 which is 900 kwh!!! That is nearly a month with no solar (and modest heating but still).

That and with V2H, you will be more resilient than most of us on-grid.

Stationary Power Generation - Fuel Cell Power Products | Ballard 1.7kW or 5kW. Hydrogen fuel cell generator.

I thought those "bans" were several years off. And I don't think they're retroactive once they go into effect.

OP says the location is Santa Clara County (southern SF Bay Area). An all electric rule for new construction is in effect for unincorporated areas in the county and also applicable for many incorporated areas (within a city's limits) too. There are similar rules for new construction in other parts of the Bay Area and state. In reviewing a list, a few also have no-gas rules for replacement equipment in existing structures.

There are lots of current bans with new construction as Elmer said - not just in CA but certainly more prevalent there.

There aren't any bans for established construction that I know of - those would be years off.

It makes a lot of sense to plan for the phase out with new construction since a house will last a long time and it is cheaper/easier to just do it that way at time of construction.

Things like solar also make sense because the roof won't need to be replaced for a long time.

Obviously - off grid and no gas (of either type) is a really challenging barrier. It is also very rare since most bans are small jurisdictions which won't usually be off-grid.