Sodium-ion batteries are finally moving toward scale, with several manufacturers announcing commercial deliveries for stationary storage. The appeal is straightforward: sodium is abundant, supply chains are simpler, and the batteries can be designed to be less prone to thermal runaway.

The tradeoff is energy density. For cars, sodium-ion still struggles to compete with top lithium chemistries. For grids, the equation changes—space is less constrained, and cost and safety matter more than squeezing extra miles from a charge.

Utilities testing the systems say the real benchmark is how the batteries behave over years of cycling in hot and cold conditions. If performance holds, sodium-ion could become a practical workhorse for renewable-heavy grids.