The cost of sodium‑zinc molten salt batteries for grid-scale energy storage

Résumé fourni par la source

Decarbonising power grids requires affordable storage to accommodate surplus wind and solar electricity over periods of hours to days. Batteries made from abundant elements offer a scalable solution. High-temperature molten salt devices such as sodium‑nickel-chloride (Na-NiCl 2 ) batteries are commercial, but their cost remains a barrier. Replacing nickel with cheaper zinc could enable the needed savings, but the techno-economic potential of sodium–zinc (Na–Zn) batteries remains untested. We present the first cost and performance assessment of a solid-electrolyte Na-ZnCl 2 battery. Using a bottom-up engineering model and Monte Carlo uncertainty analysis, we find a baseline 240-cell module achieves project-level capital costs of 246–273 USD per kWh capacity, and a levelised cost of storage (LCOS) of 164–195 USD per MWh delivered, if 2030 performance targets are met. These values undercut 2024 prices for stationary lithium-ion systems, and increasing cell capacity to 1.1 kWh or enlarging modules to 15,360 cells lowers LCOS by up to 30%, competitive with leading 4-hour lithium-ion forecasts. Sensitivity analysis shows manufacturing scale and inactive-material reduction outweigh raw-material price in driving cost, challenging the view that cheap zinc alone guarantees competitiveness. Our results provide a clear R&D roadmap and position sodium‑zinc batteries as a mineral-lean complement to lithium-ion for reliable, long-duration, grid-scale energy storage.

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