Great post of Dan Lockton's about what demand for energy actually is. Amory Lovins' remark that no-one wants "energy", they want cold beer, is of course another version of this. Which, once it had got together with this story about financing solar installation and marinated nicely in my del.icio.us queue for a while, made me wonder what kind of an organisation you would need to have the incentives set up to supply less energy.
A buyers' co-op sounds good; after all, power from the grid and the gas network would be purely a cost to it. But it's more complicated than that; you'd want it to have an incentive to put cold in the beer, whilst also having one to minimise its use of (nonrenewable) energy. And it's hard to imagine how you'd go about operationalising this. It's a micro-version of the issues in this post about the intersection of CO2 taxes and international trade.
It's a difficult problem, especially if you consider the possible surveillance costs. For example, you could assess a subscription based on your usage at joining, and then return whatever gain the co-op made over the wholesale price of power as a dividend; but this would have a huge free-rider problem.