Solar Power In Knoxville

Here is an article in today's Knoxville News Sentinel about the use of solar panels in our fair city. It would be nice if that payback interval was a bit shorter.  Also, I have questions about the lifetime of a solar panel.  Does it last long enough to get the payback and then some?

It's getting there but more breakthroughs are needed.  Increased production of the Nanosolar product might help also.