When I win the lottery (not if when) I think it would be a cool idea to start a firm that specializes in personal financing for alternative energy systems. I will call it Altenfi inc. For no more money a month than a person or business would pay on their normal on-the-grid power bill, my company will install and maintain a custom, duel source, clean energy system tailored to the customers location.....wait for it....INTEREST FREE! Ok, stop laughing. You are saying that is a really bad idea. No business can survive with a plan like that! But wait there's more. Here is the catch. During certain times of day it is not uncommon for a duel source clean energy system to be able to sell surplus energy back into the grid. And guess who would get that revenue? Altenfi of course! (for the life of the loan plus ? years.) There would be several other things built into the agreement to generate revenue for the corporation, but I don't think (with proper use of capital) that huge revenues would be needed to sustain such an operation. A lot would depend on how the corporation was structured, for instance, a public corp. would demand higher revenue than a non-profit or not for profit. But the biggest asset would be that after a while the corp. would own a huge portion of the power grid, and debt. (packaged properly) could be sold to large financial institutions.
The perks for the customer would not only be sentimental (i.e. saving the world) but the system would also offer a consistent bill without spikes during certain seasons or weather patterns or increases from power companies. (look up TVA and how customers are having to pay for the coal ash disaster in Kingston, TN which was due to negligence by TVA) It is a half-baked concept right now, but I think it's the start of a good idea. (especially coupled with cumulative energy systems, see below :)