ESS Tech Unveils 1.2 MWh Modular Sodium-Ion Battery System “ESS Bridge” with Zero Thermal Runaway for Utilities and Data Centers

Utility Dive USA

Overview

ESS Tech has launched “ESS Bridge,” a 1.2 MWh modular sodium-ion battery system designed for utility, commercial, industrial, and data center applications. This innovative system can deliver up to 4.8 MWh within a standard 20-foot container, meeting the escalating power demands of AI workloads while entirely eliminating the risk of thermal runaway. The company has already secured over $1 billion in early customer opportunities, following its announcement to procure 8.5 GWh of sodium-ion cells from Alsym Energy.

In Depth

Key Findings

ESS Tech has introduced its new “ESS Bridge” sodium-ion battery system, a modular solution tailored for utilities, commercial and industrial sectors, and particularly data centers. This system delivers 1.2 MWh of energy capacity per block, with the ability to scale up to 4.8 MWh within a conventional 20-foot battery container by integrating multiple blocks. A critical advantage of the ESS Bridge is its inherent safety profile, boasting zero risk of thermal runaway compared to lithium-ion counterparts, alongside its capability to power the rapidly expanding demands of AI workloads.

Technical & Product Details

• System Name: ESS Bridge
• Battery Type: Sodium-ion battery
• Base Module Capacity: 1.2 MWh
• Max Capacity per Container: 4.8 MWh (with multiple blocks in a 20-foot container)
• Key Features:
  • Zero thermal runaway risk
  • Addresses high-power needs of AI data centers
  • High modularity and scalability
  • Applicability for Long-Duration Energy Storage (LDES)

The ESS Bridge system leverages sodium-ion battery cells and modules sourced from Alsym Energy. ESS Tech had previously announced plans in late April 2026 to procure a total of 8.5 GWh of cells and modules from Alsym Energy. Since then, the company has successfully secured over $1 billion in early customer opportunities, underscoring strong market confidence and demand for its sodium-ion solution.

Background & Industry Context

Sodium-ion battery technology is garnering significant attention as a next-generation energy storage solution due to the abundance and lower cost of sodium compared to lithium, offering enhanced supply chain stability and cost competitiveness. These advantages are particularly valuable in sectors with extremely high power consumption and stringent safety requirements, such as data centers. As the demand for safer, more sustainable alternatives to lithium-ion batteries grows, products like the ESS Bridge are poised to address critical market needs.

Strategic Significance & Outlook

The ESS Bridge is expected to make substantial contributions to decarbonization efforts and grid stabilization by providing reliable and cost-effective energy storage in burgeoning markets like utilities and AI-driven data centers. The rapid accumulation of over $1 billion in early customer opportunities is a robust indicator of the technology’s readiness for swift commercial deployment. ESS Tech’s sodium-ion battery technology is positioned to potentially become a new standard for long-duration energy storage solutions in the coming years.

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