points by tim333 2 days ago | 0 comments
You can get a reasonable idea in the near term from the announcements of CATL and BYD who are building the things.
Like CATL announced a cost of $19 per kwh. https://electrek.co/2026/07/16/catl-sodium-ion-15000-cycle-g...
which I think is far cheaper than the prices in your links. I think they'll have a job going lower for a while as the raw materials are ~$10.
I think the actual cost to buy one now it more $40-60. The $19 is probably their target in a while.
If you spread $60 over 15000 cycles that's 0.4c per kwh stored and returned which is pretty cheap compared to what I pay for electicity (~$35c).
Plus battery assembly and installation costs (inverter, grid connection).
> If you spread $60 over 15000 cycles
A 30 year lifetime (11k cycles if charged/discharged once a day). Using a 5% discount rate the cost goes up to 0.78c/kWh for the cells. The cost goes up if it can not cycle once a day, for instance intermittent source of energy or excess capacity. And the cost goes up with all the rest of the equipment involved, and round trip efficiency.