The price of utility-scale solar power is 59 percent below where analysts thought it would be at this point back in 2010. As low as $1.92 per watt.
Sadly, the roof of my house is gabled East-West, so I'm not in a good position to get panels. $1.92 is lower than most places I've seen advertising. Looks like a good rate is about $3/watt from some stories I've read. Even at $3, the panels supposedly pay for themselves in <10 years. Still, I expect it will get a lot cheaper before it finds its water level. I plan to build a house in more than 5 but less than 10 years. That place will be energy independent, to whatever extent that's possible in MI. I'll bet getting a house to the point of using, say, 1/5 the energy of a conventional house is pretty easy these days, but I'd also bet the rate of return between 80% and 100% drops off pretty quickly. Just a guess though. I have no idea.