Progress energy has recently announced new incentives for NC customers for 2011.  With these additional incentives, a new 2 kilowatt system can be had for approximately $4,500 (after all incentives and tax credits).  After analyzing my bill, I realize that 2 kilowatts cost roughly a little over $200 per month.  If you use that much energy, the payoff for such an investment is now very long at all – approximately 3 years.  With a system warrantied for 25 years, you will get 22 years of free electricity.  In my book, that is a pretty good deal.