ESS Tech has expanded its non-lithium energy storage portfolio with the launch of Bridge, a modular 1.2 MWh sodium-ion battery energy storage system. The U.S.-made platform targets utilities, AI data centers, critical infrastructure, and commercial customers with scalable, safer energy storage.
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Product Name – ESS Bridge™ Sodium-ion BESS
Developer – ESS Tech, Inc.
Storage Capacity – 1.2 MWh per AC battery unit
Technology – Sodium-ion battery energy storage system
Target Users – Utilities, AI data centers, critical infrastructure and C&I customers
System Design – 10-foot modular, plug-and-play container
Key Feature – Air-cooled system designed to avoid thermal runaway risk
ESS Tech, Inc., a US-based developer of non-lithium energy storage technologies, has launched the ESS Bridge™, a modular sodium-ion battery energy storage system (BESS) designed to serve utilities, AI-driven data centers, critical infrastructure operators, and commercial and industrial customers.
The launch expands ESS's portfolio beyond long-duration energy storage and supports its strategy of becoming a supplier of U.S.-made, non-lithium battery storage systems covering short-, medium-, and long-duration applications. According to the company, the Bridge platform is intended to connect electricity generation with growing demand while supporting a more resilient and secure power system.
The announcement follows ESS's recent disclosure that it has generated more than $1 billion in early-stage customer opportunities since entering the sodium-ion battery market, highlighting increasing demand for alternatives to conventional lithium-ion storage, particularly from AI data centers and critical infrastructure.
Bridge is built as a 1.2 MWh AC battery energy storage unit housed in a compact 10-foot container. Each unit integrates sodium-ion battery cells, modules, racking, power conversion equipment, cabling, a battery management system (BMS), and an energy management system (EMS). The plug-and-play architecture simplifies transportation and installation while enabling plant-level monitoring, optimization, and operational control.
The modular design allows individual units to be stacked, providing up to 4.8 MWh of storage capacity within the footprint typically occupied by a conventional 20-foot battery container. The scalable architecture enables deployment across commercial facilities as well as utility-scale energy storage projects.
ESS states that Bridge has been engineered to improve operational safety compared with conventional lithium-ion systems. The sodium-ion chemistry is designed to eliminate thermal runaway fire risks and operates using simple air cooling without the need for liquid cooling systems or complex HVAC equipment. This approach reduces maintenance requirements, operational complexity, and total cost of ownership.
The system supports flexible charge and discharge durations ranging from one hour to more than sixteen hours, depending on project configuration. It is designed to operate in temperatures between -40°C and 50°C and has a 20-year operating design life, reducing the need for battery replacements or augmentation during the project lifecycle.
Bridge is also designed around abundant and widely available raw materials, enabling the development of an alternative domestic battery supply chain while reducing dependence on constrained critical minerals and exposure to geopolitical sourcing risks. ESS said the platform can help customers address concerns related to Foreign Entities of Concern (FEOC) while supporting long-term energy security objectives.