On average, commercial and industrial energy storage systems cost between $320 and $480 per kilowatt-hour (system-level, installed). Medium projects (500 to 1,000 kWh): Approximately $360 to $440. This answer depends on several factors, including the size of capacity, battery type, installation requirements, and local market conditions. The paragraphs below outline the major costs and provide a reasonable price range for C&I ESS. Voltage Capacity: High-voltage cabinets (1,500V) cost 12-18% more than 1,000V systems but offer better efficiency.