> Also, why bring up batteries? You don't need batteries to produce solar. If you have extra power, most people are feeding it into the grid, not batteries.

Because feeding back to the grid is only a sustainable solution when a minimal number of entities are doing it. What happens when the majority of entities are feeding back to the grid? Where is all that energy supposed to go? The answer, of course, is storage.

And this isn't just some made up problem either; it happens right now with a different solution. There's a huge slack in power demand at night. Sometimes enough that the power providers will offer deep discounts to bulk buyers to get rid of excess supply. So you see some industries that use massive amounts of power, like aluminum refineries, shift to mostly night operations. But shifting demand around will only help so much.

Now, while distributed generation is fine, I don't think distributed storage is going to work. Storage cost (both economic and ecologic) and efficiencies are simply much better scaled up.