I guess my point is that cars and phones drove battery research towards energy density, but I still have three cord of firewood in an 8*12ft shed at the end of my driveway. Energy density is my last concern.
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Yeah, that makes sense! The drive has been not only for higher density, but also lower cost. Sodium batteries were investigated for cost reasons (to avoid the Lithium) and it turns out that density isn’t as good (for now), but that’s okay for some cars and great for stationary storage. Enough demand to drive innovation. A cord of wood is hard to beat on cost!
My understanding on sodium is that it’s still early days. Most “sodium” batteries shipping today are hybrids with lithium (two sections, one bms) with poor cycle lifetimes, so there is a lot to figure out still. I haven’t personally seen or heard about CATL’s sodium batteries in the real world yet.
For those of us outside the US and used to other units, a cord [1] is of course 128 cubic feet or roughly 3.62 cubic meters. The wood is supposed to be well stacked (aligned, parallel, touching and compact) and if so, one cord is a pile measuring e.g. 4x8x4 feet. Wow, three cord is "a lot", in other words.
Cords of wood are usually around 18 million BTU of potential energy, which is 5000+ kWh. Wood stove efficiencies are all over the place, but modern ones are in the 70% range.