Somebody did that here in Chicago about 5 years back, seemed a bit too complicated and expensive to me. I think it was in Lincoln park. (affluent area on the North side). Anyway, the savings from what I heard were about 30% reduction in utilities. The problem is that it was fairly new, the panels themselves were pricy, and since they were new, approvals from the City for permits took a little longer.
I think that they actually had to submit the project to Developer services. Which is an independant Architectural/Engineering firm that the City sub-contracts to in order to expedite the building permit process. (which in itself is very time consuming and complicated) Not mention expensive! Developer services charges about $30,000 and up for some projects, that is just to review, keep in mind that the cost of the permit itself is seperate. But people with money and in a hurry won't mind paying extra.
Then again that was a long time ago, I haven't really heard too much more about it. But since I only work on my own projects, I have limited exposure to the permitting process.
My younger brother however, owns a building permit expediting company, I'm sure he's seen a lot more of this, and I am sure that approvals are a lot faster and they probably have a better system in place where inhouse Building department examiners can review these projects.
I will ask him today when I see him. Keep in mind I'm talking about Chicago, every city is different, but as far as obtaining permits goes, Chicago and New york City are the toughest.
I think that you are on the right track and eventually it will be very big. Not only that your city may not be as tough in issuing permits as Chicago and New York.
this type of power will probably become common, or even mandatory. So now is actually the best time to get into it. It sounds like a plan.