Many commenters are missing two big advantages of this system. (1) This is a micro-grid. "Microgrids minimise the amount of energy lost through transmission; as an estimated 5% of electricity created in the US is lost in transit, microgrids provide an efficient alternative. The Brooklyn microgrid also economically benefits those who have installed solar panels." http://www.power-technology.com/features/featurethe-brooklyn...

(2) The market is peer-to-peer, so prices for buying and selling aren't dictated by a monopoly and monopsony power which could ripoff both the regular homeowners and solar-panel owners, but rather a competitive market.

(3) The grid is p2p and thus is disaster-resilient. Think back to Hurricane Sandy and the 2003 NY State blackout.