One thing I didn't put in the spreadsheet was consideration of off-grid power. The problem with off-grid systems is it's hard to do good energy storage. So often you will get a system where the batteries are well charged and the energy produced by the panels is discarded. You can't keep the batteries in deep discharge all the time, it's not good for them. Newer battery technologies may help that.

But anyway, with an off-grid you must then add a factor describing how much of the energy you will actually get to use. If you throw away a lot, it's harder and harder to make your system economical. For the off-grid person, "economical" may mean compared to generators or other forms of power, rather than compared to the grid. Generators, polluting as they are, only are on when you truly need power, and combined with batteries you will use all their power. (Generators without batteries can also be wasteful if you run them with less load than their idle power production.)
Grid-tie is just so much better at this, which is one reason a lot of the rebates and credits only apply to grid-tie. (The other is demand side management.)

A good design is probably just enough solar so you will always use all of it, some batteries to store rare excess and a smaller generator for high demand or when the batteries get too low. Plus some wind if practical and hydro if available. Or of course, solar, wind or hydro with grid tie. Batteries with grid-tie may be a good idea if you want just a little backup during grid outages, though a generator may make more sense since for most people, grid outages are quite rare, so the pollution question is minor.

Some people think they are green because they take a solar panel on camping trips. That's not green at all, since the panel consumed a year or more of its own output to be manufactured. (Used to be as much as 4 years.) Unless you camp all the time, you're just storing energy and not being particularly green.