This sounds like a brilliant concept though I'd like to hear more about what this would involve. Would it run like a community owned ESCO? I know these have been very successful in places like scandinavia where they set up community owned, biomass powered, combined heat and power stations. I imagine a feasibility study would be required. Have you spoken to anyone in Sustainable Haringey about this? I suggest you start with their energy group. Sorry if you're already involved with them!
You maybe interested another energy co-operative down Peckham way. Went to one of their meetings a couple of years ago; http://peckhampower.org/node/332