I played around with a solar savings calculator a while back out of curiosity, there is an excel spreadsheet on an Australian website I believe that's pretty thorough, but it's not the only one.
In short, I don't think it pays to sell electricity back to any utility (they pay back 1/2 of what they charge you) and a battery system probably won't be worth it unless you truly want to stay off the grid. Get a system that's enough for your maximum daytime usage, that's the fastest way to break even, and spend the least amount of money. For such a system, given my local electricity rates, the break even point was ~15 yrs. a decade ago, and it's 7-8 years now. If you can find cheaper panels/inverter the break even can be ~6 years, after which you'll only be left with a much smaller electricity bill. It even makes sense to add panels later if your usage increases.
The way the break even time has been shortening is very exciting, more people will be able to afford it; and if you can, it's a no-brainer to do it sooner rather than wait.
In short, I don't think it pays to sell electricity back to any utility (they pay back 1/2 of what they charge you) and a battery system probably won't be worth it unless you truly want to stay off the grid. Get a system that's enough for your maximum daytime usage, that's the fastest way to break even, and spend the least amount of money. For such a system, given my local electricity rates, the break even point was ~15 yrs. a decade ago, and it's 7-8 years now. If you can find cheaper panels/inverter the break even can be ~6 years, after which you'll only be left with a much smaller electricity bill. It even makes sense to add panels later if your usage increases.
The way the break even time has been shortening is very exciting, more people will be able to afford it; and if you can, it's a no-brainer to do it sooner rather than wait.