Rushing to the nearest browser in case a patent application was necessary, we became a slightly despondent upon seeing a bunch of articles like this one on microgrids and what the EPRI are getting up to. That said, it's great to see this kind of stuff getting mindshare.
So what, if anything, is still missing? To see this come true, it seems like we'd have to work our how the power companies would still make money in our community-spirited utopian electricity supplying future. So perhaps we can still contribute by bringing some economics into the solution.
Someone has to provide that infrastructure - the grid we'd all have to be connected to in order to exchange electrical capacity. That sounds like something someone should be paid to provide. So perhaps there is a subscription fee? Or maybe we can do one better - how about a variable charge based on each household's net balance at the end of every month/quarter/year? The closer you are to netting out (producing the same number of kilowatt hours you consume) the closer to zero the bill gets.
The beauty of that model is it incentivizes consumers to be as self-sufficient as possible and disincents (is that even a word?) waste. The expected impact of such a price control is for participating individuals to want to align their production with their consumption - probably by boosting the capabilities of the former while working out efficiencies in the latter.
Reducing overconsumption is probably a no-brainer, but you could look at reducing overproduction both ways. On the one hand, overproducers supply overconsumers and we'd need that, but on the other hand we wouldn't want participating individuals to profit from overproduction. Ultimately all overproduction is wasteful (by definition if nothing else) so there should still be a price for it, a lower price than overconsumption, but not as low as netting out.
Well that was all kind of off-topic, but I hope you enjoyed it nevertheless. There are some intriguing engineering challenges in the basic problems inherent in sustaining our society, and if we gave this kind of stuff a little more attention, we'd all be living in a much better world before you know it.