The main objective of this project was to demonstrate Aquion’s low cost, grid-scale, ambient temperature sodium ion energy storage device. The centerpiece of the technology is a novel hybrid energy storage chemistry that has been proven in a laboratory environment. The objective was to translate these groundbreaking results from the small-batch, small-cell test environment to the pilot scale to enable significant numbers of multiple ampere-hour cells to be manufactured and assembled into test batteries. Aquion developed a proof of concept demonstration unit that showed similar performance and major cost improvement over existing technologies. Beyond minimizing cell and system cost, Aquion built a technology that is safe, environmentally benign and durable over many thousands of cycles as used in a variety of grid support roles.