Solar Today (an excellent magazine focused on Solar energy) just ran an article going into the real costs of a Photovoltaic system. It is short and sweet with some good insights.
The conclusion is that”….in the case of solar, the sun is going to come up every day, so there is practically no downside. It’s like buying a bond, but one that returns 12%. It’s the safest, highest return bond, anyone will ever have an opportunity to see.”