There is “backup up power” using batteries and PV. The brand name is the Outback System.
I am putting one in my house as soon as things slow down a little
Your underhouse area should be fine for the equipment and the batteries. You want to be weathertight, and also have the ability to secure. I would definitely put a good lock on that door after the Outback goes in.
Good part is, that if HECO goes down, you won’t even notice a blip at all, and you will just have power. You have to pick which circuits are your emergency circuits
1. Refrigerator
2. Microwave
3. Some lights to allow bathroom, kitchen use, and travel from bedroom areas
4. Some receptacles for Phone, Modem, Router
5. Computer
6. Security system
7. Exterior lighting for security/motion lights
8. Lights at the Outback, along with a few receptacles nearby in case you have to do some work on things.
Usually we try to keep that to 6 circuits, because you don’t want to put too much on it, and end up draining your batteries when you don’t want to, say if the power goes off and you are not home.
Typical is 8 batteries, too produce around 10kWH of storage.
Cost around $10,000, but as part of PV system, you can get tax credits, resulting in around $3,500 which is not bad.
Compare that to a Honda generator, $2100, accessories $200, electrical transfer switch $800, electrician to hook it up say $1000, and you are looking at $4100, plus you need to buy and keep gas on hand, and rotate your supply of gas every so often so it doesn’t go bad.
You can add batteries, to double your storage, at any time in the future. The batteries should last around 10 years under emergency use.
Be glad to quote this one, I like them. Takes me about 3 hours to quote one though, because all the control and switching components are pretty complex.
Also there are ramifications on the number of inverters and the related tie-in to the building electrical system, and thus the tax credits. These are issues that can readily be dealt with, just be aware that they are there.