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ESS Tech, Inc. manufactures and deploys long-duration energy storage systems using iron flow battery technology. Headquartered in Wilsonville, Oregon, the company provides utility-scale energy storage solutions designed to support renewable energy integration and grid stability. Its flagship Energy Warehouse product utilizes an environmentally safe, all-iron flow battery chemistry that stores energy for 4 to 12 hours, targeting applications where lithium-ion batteries face economic or operational limitations. Unlike conventional battery technologies, ESS's systems use abundant iron, salt, and water, positioning them as a sustainable alternative with minimal fire risk and long operational lifespans exceeding 20 years. The company serves utilities, independent power producers, and commercial industrial customers primarily in North America, with growing international interest. ESS operates a manufacturing facility in Wilsonville capable of producing systems at commercial scale. The company went public through a SPAC merger in October 2021, providing capital to expand production capacity and accelerate deployments. Recent initiatives focus on scaling manufacturing operations, reducing production costs, and expanding its project pipeline as demand for long-duration energy storage grows alongside renewable energy deployment. ESS competes in the emerging long-duration storage market against both alternative flow battery developers and traditional lithium-ion solutions, differentiating itself through safety profile, resource availability, and duration capabilities.