However, I can choose to put power onto the grid. In fact, I'm currently in the approval process to do so. But that's only after I've had solar for 2 years (since May 2021) a now all-electric house (since Nov 2021), an EV (since June 2022), and upgraded my solar system to account for all of that (finished Aug 31, 2022). And my inverters have a good data export recording many things in 5-minute candles, which I import into a homemade SQL Server database and do analysis on (I'm a software engineer, specializing mainly on the back-end/data side). I then made a C# app to recreate the past 12 months of power bills according to different billing plans my power utility offers. One of which has to do with purchasing my excess power, but for 1/4th the price we pay (actually 1/5th after they add riders and state tax to the power we buy). The problem with the power purchase rate plan, it comes with a few new expenses, including either a demand charge or a flat monthly fee. The flat monthly fee would be horrendous (adding $135/month). The demand charge would vary, depending the highest amount of kW in power I pulled during the billing period. That's where analyzing the inverter data comes in. I was able to determine that in most months, the dollars given to me for purchasing power would be more than the dollars I give them for the demand. Thus, I'm signing up for the power purchase plan.
But if they ever change their polices, or if my wife and I change our power consumption habits so that the power purchase plan hurts me more than helps me, I'll shut it off. The same for if they change the policy that allows me to keep my solar power on when the grid goes down (other solar users have to turn their home power off to prevent their solar power from harming linemen working on downed power lines). My inverters are allowed to keep powering my home when the grid is down because my inverters have the feature to not try to put power onto the grid when the grid is down. Thus, the power purchase plan doesn't make me lose the feature of keeping power on when the rest of the neighborhood is down. At least for now.
That's my suggestion to you. If you go solar, always make sure you're the one in control (which you would be according to your "no grid connect" statement). And if you decide to sell excess power to the grid, fine, but again as long as you're in control and can disable it if you desire.
Perhaps even more important is to look for other ways to save energy, such as making sure you have as much insulation as is feasible, seal cracks, etc. When I replaced my two natural gas appliances with electric ones (probably not a good idea in Oregon), I made them highly efficient ones. I now have a variable speed heat pump and variable speed air handler to cool and heat the home with heat strips for the few times it's too cold for the heat pump.
I also now have a hybrid water heater, which heats the water tank with its built-in heat pump. Not only does that draw low power (300W vs 4kW in a normal electric water heater, though admittedly it takes 2-5 hours to reheat after my wife and I take back-to-back showers, vs 30 minutes to 45 minutes in a normal water heater). It also gives me a free cold air byproduct that I use during the warm 7-8 months to help cool my home. There's now an air receiver in the floor of the closet the water heater is in. During the winter months I duct the cold air byproduct into the attic. During the summer months I let the cold air byproduct fall to the floor to be picked up by the home air receiver, which is almost always drawing in air because the variable speed heat pump and air handler are almost always running, even if in low power mode. Thus, for the 2-3 hours in the summer the water heater runs, my home heat pump doesn't have to work as hard to cool the air in the home. Last but not least, the air intake of the water heater is drawing air from the attic (thanks to a duct). Thus, when the water heater's heat pump works to pull heat from the air, it doesn't have to work as hard because the air is usually warm from the attic (sometimes over 100F here in Alabama).
And if you get an EV and get solar, you might ought to consider having two charging ports to plus your EV in: one constantly powered and one intermittently powered. That means your inverter(s) have to have a feature like what mine calls Smart Load. Basically, whenever my home solar batteries are charged to a configurable amount (right now it's set to 70%), my inverters power a separate electrical panel. One of my 240V NEMA 14-50 outlets for charging the EV is tied to that panel. The other EV outlet is tied to the regular electrical panel (constantly powered). So if we come home in the EV with it already charged more than enough for the next day (my wife likes it to be at least 120 miles), we plug it into the intermittent outlet. That outlet doesn't guarantee us power, but it guarantees us that whatever power we get won't add to the power bill (because the home solar batteries are charged more than enough to power the home through the night). And if the EV is still plugged to it the next day after the sun comes out, charging will automatically begin when the home solar batteries are charged enough. (But if we come home needing the EV charged even if it might add to power bill, we plug the EV into the constantly powered outlet.) That one charging technique makes almost all of our local EV driving free. When our EV battery is charged 80%, it gets 230 miles. The 230 miles top off point minus the 120 miles my wife wants, gives us 110 miles of driving for a few days in a row (say 40-50 miles on an average day) that we're liable to get free solar power on to keep charging the EV with free power.
Wow, that is some great information. Thanks for sharing your experience! Will definitely be filing that one for future reference.