Agreed, energy density isn’t really very relevant from a grid perspective; space is pretty abundant when you’re talking about an entire grid region.

I was definitely hinting at the dispatch-ability of PV in my other comments, but you totally have the idea.

And it’s going to be batteries totally. At the publicly owned power utility I work at, I actually was in the energy storage technology group for a small stint. Whole purpose of the group was just running feasibility analyses on installing utility-scale batteries.

The core issue is batteries at scale are a completely infant technology. We had proposals that were literally straight out of graduate research. That’s great and all for the technology development, but my company only cares about reliability, dispatch-ability, and competitive rates. We’re not interested in prototypes.

I’d keep a close eye on molten salt batteries and flow batteries. I think those are the most developed. Especially flow batteries, companies like Sumitomo are making pretty big progress in Japan, and starting to move over to the US.

But again, issue is scale. A useful battery for a medium-sized utility is something like 50MW at 4 hours duration (equivalent to something like a peaker unit, though not all that useful for nighttime baseload). And this battery would be something in the range of like $250M. And a comparable gas peaker unit, about $80M, and that unit can run 24/7.

So the economics at utility scale are getting there, but we’re not there yet.

I do look forward to a 99% solar and battery grid though. With that 1% filled by emergency natural gas.