Our mission At ESS Inc., our mission is to bring to market the cleanest, lowest-cost long-duration energy storage systems. We are the catalyst for a sustainable energy future. Our history Established in 2011, ESS Inc. manufactures low-cost, long-duration iron flow batteries for commercial and utility-scale energy storage applications requiring 4+ hours of flexible energy capacity. Our long-duration energy storage platforms, the Energy Warehouse™ (EW) and Energy Center™(EC), use iron, salt, and water for the electrolyte, and deliver an environmentally safe, long-life energy storage solution for the world’s renewable energy infrastructure.