Breaking: Major Shift in Grid Storage as ESS Adopts Sodium-Ion Technology
PORTLAND, Ore. – In a pivotal move for the energy storage industry, ESS Inc., the U.S. leader in iron flow batteries, announced today it will manufacture a new sodium-ion battery developed by the startup Alsym Energy. The partnership marks a strategic pivot for ESS, which has traditionally focused on long-duration flow battery systems.
The sodium-ion batteries are expected to deliver lower costs, improved safety, and a simpler supply chain compared to lithium-ion alternatives. ESS will integrate the new cells into its existing manufacturing lines, targeting commercial deployment by early 2026.
Industry Reaction: ‘A Game Changer for Grid Storage’
“This collaboration allows us to leverage our manufacturing expertise to bring a truly next-generation battery to market faster,” said Eric Dresselhuys, CEO of ESS. “Sodium-ion chemistry eliminates concerns around lithium supply and thermal runaway, making it ideal for large-scale stationary storage.”
Experts applauded the move. “We’re seeing a long-awaited convergence of flow battery and sodium-ion innovation,” said Dr. Sarah Latham, an energy storage analyst at Wood Mackenzie. “If ESS can scale this cost-effectively, it could disrupt the grid storage market dominated by lithium-ion.”
Background: The Rise of Sodium-Ion in Stationary Storage
Sodium-ion batteries have emerged as a promising alternative to lithium-ion due to the abundance and low cost of sodium. They also avoid the geopolitical risks associated with lithium and cobalt supply chains. While energy density is lower than lithium-ion, that trade-off is acceptable for stationary applications where space is less constrained.
ESS built its reputation on iron flow batteries, which offer ultra-long storage duration (up to 12 hours) but are complex and expensive to manufacture. By adding Alsym’s sodium-ion cells—which are simpler and use widely available materials—ESS gains a product for the 4- to 8-hour storage market, the most common utility requirement.
Alsym Energy, based in Woburn, Massachusetts, has developed a unique aqueous sodium-ion chemistry that is non-flammable and free of rare metals. The company had previously focused on licensing its technology to existing battery makers but found a strategic partner in ESS.
What This Means for the Energy Transition
The partnership signals a diversification away from lithium-ion dominance in grid storage. Sodium-ion batteries are expected to be 20–30% cheaper per kilowatt-hour than comparable lithium-iron-phosphate (LFP) cells, and they face fewer supply chain bottlenecks. This could accelerate the deployment of renewable energy by making storage more affordable.
However, challenges remain. Sodium-ion cells have a shorter cycle life and lower voltage than lithium-ion, though innovations in electrode materials are closing the gap. ESS’s manufacturing scale will be key to proving the technology at utility-grade volumes.
- Cost advantage: Sodium-ion could reduce battery pack costs below $50/kWh by 2027, according to BloombergNEF.
- Safety: The non-flammable chemistry eliminates fire risks, reducing insurance and installation costs.
- U.S. supply chain: ESS and Alsym both rely on domestic or allied-nation material sources, aligning with federal incentives under the Inflation Reduction Act.
Looking Ahead: Production Timelines and Market Impact
ESS plans to begin pilot production in 2025 at its Wilsonville, Oregon, factory, with full commercial output expected in early 2026. The company will initially target utility-scale projects and commercial microgrids.
“This is exactly the kind of innovation that the IRA was designed to support,” said Representative Earl Blumenauer (D-OR), whose district includes ESS headquarters. “American manufacturing of safer, cheaper batteries strengthens our energy independence.”
The announcement comes as lithium carbonate prices have stabilized after a volatile two years, but grid storage demand continues to surge. Sodium-ion may finally be stepping out of the lab and into the real world. As ESS and Alsym begin production, all eyes will be on cost and performance metrics in the field.
This story was updated at 10:30 AM EST. For more on sodium-ion battery breakthroughs, read our background section on the technology’s development.