Reason for optimism?

The Economist has a short article on the potential for "distributed generators" and large scale batteries to beat down things like big coal.  It starts:

WHO needs the power grid when you can generate and store your own electricity cheaply and reliably? Such a world is drawing nearer: good news for consumers, but a potential shock for utility companies. That is the conclusion of a report this week by Morgan Stanley, an investment bank, which predicts that ever-cheaper solar and other renewable-energy sources, combined with better and more plentiful batteries, will allow many businesses and other electricity users to cut the cord on their electricity providers.

Tesla Motors, an American maker of electric cars, recently said it will build a “gigafactory”, which by 2020 will turn out as many lithium-ion batteries as the whole world produced last year. These batteries can do more than power cars; they can also store electricity which is produced when it is not needed, and discharge it when it is.