|May 15th, 2021
We currently have two sources of standard 120V power in a blackout:SPS; the panels themselves are rated for a total of 5 kW.)
They do have downsides, though. The battery has a limited capacity, and the solar requires the sun to be shining, the panels to be clear, and the sun to be in the right part of the sky. They complement each other somewhat, using the battery to time-shift, but there are many blackout situations (ex: winter storm) where once the battery is depleted the solar wouldn't give us anything.
A fossil fuel generator is potentially a good fit here. While it doesn't have the long-term properties of solar, fuel is cheap enough that you can have a capacity far larger than you would want to spend on batteries.
For example, a generator can turn a five gallon can of gas into ~15 kWh. That's already much more than my battery, and each additional can of gas is far cheaper than a large battery.
On the other hand, gas is a pain. It turns to varnish in a few months and (especially if it has some ethanol) it pulls in water from the air, so even if you're using fuel stabilizer you want to rotate it. It's not safe or legal to store in your basement, and the temperature fluctuations of storing it outdoors aren't great for it either. Storing gas in your car's gas tank could be good, since it will get automatically rotated, but most cars now have anti-siphon filters.
Propane seems more attractive: it doesn't go bad, you can store it outdoors if you keep it out of direct sun, and while it's less efficient than gasoline a 20lb propane tank still gets you ~10 kWh.
You can get inverter generators that can take both gasoline and propane (ex: $535), which seems like a good combination? Thoughts?