Terry, you've got 2 separate questions here. An an investor, I would certainly be asking "What's the benefit here for me as a real estate investor?" I mean, if I'm not paying for utilities....so what's the point?
Now if it's my own home, ok, there's some benefit...but I do feel that if you have the resources to be "energy responsible" then certainly consider solar. I would not anticipate ever having enough savings to justify the costs. The average homeowner lives in their home for 7 years. That's right about the "break even" point in most studies. There are some energy jurisdictions that allow you to "sell back" your overages - meaning, you create more energy than you use, so the energy grid buys what energy you create from you. But even in those places it still takes years to earn your money back. If you've got the money, go for it. But if this would keep you strapped for cash, I would tell you to cut costs in other ways around the home. This is a pretty reasonably unbiased article: https://www.marketwatch.com/picks/guides/home-improvement/are-solar-panels-worth-it/