US-based Alsym Energy has signed a strategic partnership with California renewable energy developer Juniper Energy to deploy 500MWh of sodium-ion battery energy storage systems (BESS) across California, in what the companies describe as a move away from lithium-ion chemistries in high-temperature environments.
The agreement centres on Alsym’s non-flammable Na-Series sodium-ion batteries, which the companies said are designed to operate without active cooling systems even in desert climates such as California’s Mojave region.
The latest deal follows Alsym’s recently announced 8.5GWh partnership with ESS Tech, previously reported by BESTmag, as the Massachusetts battery developer continues to push sodium-ion technology into grid-scale storage markets.
According to the companies, the systems will target utility-scale projects where thermal management, fire safety and operational costs are major concerns. Unlike conventional lithium-ion systems, Alsym said its sodium-ion chemistry avoids thermal runaway and can use passive cooling rather than energy-intensive HVAC systems.
Alsym’s sodium solution
Keith McDaniels, founder and managing partner of Juniper Energy, said: “After several years of evaluating the non-lithium landscape, it became clear that sodium-ion – and specifically Alsym’s Na-Series – is the premier solution for the next generation of California’s grid.”
Mukesh Chatter, chief executive officer and co-founder of Alsym Energy, said the technology had been designed specifically for “warmer environments” where lithium-ion systems face operational limitations.
“Our Na-Series technology was built for exactly this: providing high-performance, fast-charging storage that doesn’t require complex cooling or risk community safety,” Chatter said.
The companies also said the partnership is intended to maximise US domestic-content incentives and Department of Energy support by using US-manufactured battery systems.
Alsym claims its sodium-ion batteries offer an operating temperature range of -40°C to 60°C, more than 10,000 cycles and round-trip efficiency above 95%, although energy density remains below comparable lithium iron phosphate (LFP) systems.
The deployment adds to growing commercial momentum for sodium-ion batteries in stationary storage applications, particularly as developers seek alternatives to lithium-ion systems amid concerns over fire safety, HVAC costs and supply-chain dependence on critical minerals.
