It has always been an open question in my mind... is tesla energy an industrial product for power companies or a consumer product? I will be curious to see how it plays out, but very long term, I think it will be a consumer product. Tony Seba predicts the cost of renewable energy will drop below the cost of transmission.
My expecation for the distant future is it'll be both. There will be areas of the world where an individual household can reasonably build their own power system and be their own grid. Especially in a world where renewably energy is cheaper than the cost of transmission.
There are also plenty of areas in the world (like the Pacific NW where I live), where the renewable energy will need to be seasonably storable (not just for day or 2, or a week). One tangible example - the 10kw solar PV system I have on my roof routinely clears 60KWh produced during the summer months, and routinely falls below 5 KWh for a day of production during the depths of winter (sometimes <1KWh). Great for electric AC during the summer - bad for electric heat (whether heat pump or something else) during the winter.
And the shortfall is so high, I would really need seasonal storage to capture sunshine in the summer so I could spend it during the winter.
That being said, anywhere with particularly good solar and a particularly recalcitrant / expensive local utility, is likely to find signficiant grid defection. I think anywhere with local utilities that are trying hard to figure out how they can transform the grid will find that there is still a role for central energy production and transmission. It might start looking more like each household takes care of their routine / baseload electricity, and the utility is called on for extreme temps and power usage, or to trickle replace energy shortfall, or I don't know.
End result - I see both business models and uses for batteries for as far into the future as I'm alive (say 2060). Maybe in a couple of centuries, every building will be optimized for efficiency, every surface will collect energy from the sun, and we'll be so awash in solar energy that I won't need a transmission grid here in the PNW for my heating during a week or 3 of heavy clouds / no sun / cold weather in the winter.
