Hi Jane, Welcome to Permies!!
AHH, what a wonderful dream! I am slightly envious as you are at the start of an exciting journey. But as for solar, I would probably need a bit more to go from. Specifically, I need to know how many watts you would use in a day and that can be a difficult number to answer. The good news is that you are not using electricity for heating, which I personally think is the worst use for solar-electric (why generate electrons just to turn them into heat when there are SOOOOO many other ways to create heat). But maybe a reasonable list of questions to ask would look like the following:
Are you going to use electricity for any of the following things:
Laundry (washing)
Laundry (drying)
Hot water
Air conditioning?
Computer use
Other electronics
Lighting needs
Medical devices
Power tools, especially cordless (and thus the need for charging)
Kitchen devices
*Microwave (huge demand over short time!)
*Blender
*Toaster/air fryer (again, looks like a microwave!)
Fridge
Outside Fridge/Freezer
Anything else
I suspect that at a bare-bones system, you could run all of these things from a small, 2200 watt portable generator (I know, not solar, but it gives us some numbers). This would leave almost no room for growth and you might have to load-shift which means you would have to watch which devices were being used at the same time (no microwave and air fryer!).
I would think that a more realistic number would be something like 4-5KW. This is not a big deal to get either on a roof or on a stand nearby.
But then we get into the problematic issues.
Realistically, on a perfect day, you have about 5 peak hours from which to generate electricity. You can still generate from the other times, but it will drop off rapidly. This brings us to the question of whether or not you want to store electricity off grid or be a grid-tie system. They each have their ups and downs.
Off Grid
This is the ultimate way to be really independent, but you will have to buy the batteries and they are not cheap, especially when you calculate just how much electricity you want to store. I know it seems obvious, but solar panels are useless at night and are minimal at best in inclement weather. Honestly, you have to decide just how much you want, but a common figure to work with is 3 days. Consider what 3 days worth of electricity looks like in batteries (and I suggest LiFePo4 batteries for this option). If we go with a 4Kw system that generates 20 Kw-H (Kilowatt Hours) during those 5 peak hours then you would want 60 Kw-H worth of batteries. If you store electricity in a 12v 100 ah battery (a common size and voltage), then you are looking at 1.2 Kw-H per battery. At a bare minimum, you would want 17 of those batteries. I took a quick look, a a mid-range battery meeting those specs looks like this one here
https://www.eco-worthy.com/products/lifepo4-12v-100ah-lithium-iron-phosphate-battery?srsltid=AfmBOopCxnjvVOju3GupEq6zhxr7oXzAW5hfgn-tUNWBqi_fbzWYJe6WrJw
It costs $190 at the time of writing, down from $280. That's $3230 for the batteries. Realistically, these would probably need to be purchased in pairs so bumps the price to 3420.
Then we have to consider the charger (go with MPPT!) and some extra components. Expect up to about $500.
So from there you might think about going grid-tie and I completely understand. But when you do, you are going to pay a monthly hookup fee (probably $20). There is also some specialized components that are designed to prevent backflow down the line in an emergency. The issue is that if there is a power outage in the area and you are producing electricity, any electrical worker could get a nasty to fatal shock even if he thinks that the power is off (that is, as coming from the power plant). But since you are generating electricity from your house and feeding backwards, a line could be live even when it should be dead. This is a real concern and it adds a non-trivial amount to the cost. Also, the power company may or may not buy electricity from you and pay you for the same electricity for the same price!
And it only gets more complicated.
Please don't look at this as me being anti-solar. I am not. But if you do go solar, go in with eyes wide open.
But short version, if I were you and just guessing at this point, I would go with a 3kw-4kw system, but this will vary drastically on your location and usage.
I have no idea if this helped or not, but maybe it gives a starting point.
Let me know what you think!!!
Eric
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