If you want to do solar for the environment, fine - I won't fault you - but if you are doing it to save/make money, there are better places to invest.
PG&E: https://seekingalpha.com/article/4441976-formerly-bankrupt-p...
Part of my reason for thinking about solar is that if I'm going to spend 10k on a backup generator it might be far smarter to spend that on solar. For me the invest and pay cycle doesn't address the problem I'm solving. But I absolutely learned something today.
Anyway, if you want to use it as a backup, you'll need to oversize the solar so the battery can get you through power outages on cloudy days.
At that point PG&E will pay you 10-20% market rate for the excess energy you produce on most days. It's much better to dump those electrons into an EV battery than into the grid. My commute costs $4/week in electricity I don't send to PG&E, vs 20x that for the gas for the same commute.
(The EV gets 4.5 miles/kWh, and PG&E pays $0.04 / kWh, or $.008/mile. The old car gets 30mpg. At $5/gallon, that's $0.16/mile)
The punchline: Budget money for an EV for each of your household's commutes when you purchase the solar panels. Regardless if whether you buy panels, consider charging at work, assuming your employer subsidizes it and/or has solar panels.
(Also, check the milage on the EV you want. 3-5 mi/kWh is typical, but they can vary from 1 to 7.)
Its been a few years since I did the math, but last time I was quoted about 60K for a complete system - 60K at 5% dividend (NGG at the time), would give me $3K per year, enough to cover my bill.
AT the end of 20-30 years, a solar system will be worth nothing, or almost nothing, whereas I will still own the same stock in the same company hopefully the stock will have appreciated as well), and will still be covering my electric bill.
This of course makes lots of assumptions: I need to invest in company that will still be around for decades, that electric costs don't go thru the roof during that time, and the dividend doesn't go away etc. - but also would have to make assumptions about how long a solar system would last - its impossible for any of us to see out 30 years, but for the time being, I feel like on a purely financial basis, it didn't make sense for me today.
But trust me, I would love to pay one sunk cost today and not have to pay an electric bill for the next 30+ years, if only I could see that far in the future with some certainty.
We have some of the cheapest rates in the US, due to our nuclear, so our state incentives are fairly good to compensate. Nuclear may be discontinued, but given recent events I’m less sure. Either way I think we only have upside on the ROI due to rate changes.