US Firms Partner to Build 8.5 GWh of Safer Batteries

American energy storage is getting a major upgrade that's safer, cleaner, and entirely homemade.

ESS Tech just announced plans to add 8.5 gigawatt-hours of sodium-ion batteries to its lineup through a partnership with Massachusetts-based Alsym Energy. That's enough storage capacity to power hundreds of thousands of homes during peak demand.

Here's what makes this exciting: these batteries won't burn. Unlike lithium-ion batteries that can catch fire or explode under stress, Alsym's sodium-ion technology is completely non-flammable and non-toxic.

The partnership marks ESS Tech's bold move into short and medium-duration energy storage, a market that lithium batteries have dominated for years. By offering an alternative chemistry that balances safety, performance, and cost, the companies are betting they can win over utilities and grid operators looking for reliable backup power.

The timing couldn't be better for American manufacturing. Alsym officially launched its Na-Series batteries in October 2025, emphasizing that every material comes from sources outside the list of "foreign entities of concern." That means no dependence on overseas supply chains that have left the US vulnerable in the past.

The Ripple Effect

This partnership represents more than just new batteries hitting the market. It signals a fundamental shift in how America approaches energy independence and grid reliability.

Sodium-ion technology uses abundant, cheap materials that don't require mining rare minerals from conflict zones. The lower production costs could translate to what the industry calls a better "levelized cost of storage," making clean energy more affordable for everyone.

For communities transitioning to renewable power, safer batteries mean solar and wind farms can be built closer to neighborhoods without fire risks. That could accelerate the clean energy transition in populated areas where lithium battery installations have faced pushback.

ESS Tech's expansion into multiple storage durations creates flexibility for grid operators juggling everything from brief evening demand spikes to multi-day weather events. Having options beyond lithium gives utilities backup plans when supply chains tighten or prices spike.

The partnership also keeps critical manufacturing jobs and expertise on American soil, building the kind of domestic capability that protects against future shortages.

As renewable energy becomes the backbone of America's power grid, having safe, affordable, American-made batteries to store that power isn't just good business—it's essential infrastructure for a cleaner future.