We wired a couple houses that used solar panels. The home owners got a gov't grant that paid for "most" of the upfront costs. The company installing the solar paneling said that it would take about five years for the homeowners to recover their out of pocket expenses from their lowered power bills. At about that same time, the homeowners could expect to have to replace their solar panels.
I looked at this back in 2009 & the minimum payoff time was 17 years. I didn't include cost of capital at all either.
I'm also interested in how rich these people are? Obama loves to give $6000 subsidies to rich people who are the only ones who can afford a $40,000 Chevy Volt. Same with solar panels. If I were rich then I'd buy some because I think they're cool & you all would pay for my toy. But I can't afford them so there won't be a subsidy for poor me.