This study reports the results of a comprehensive national study on the performance and operational experiences of cool thermal energy storage (TES) systems. The data analyses and observations presented are based on the information collected from a survey of people associated with the existing TES systems. Over 300 owner/operators were contacted and expressed their willingness to participate in the survey. Nearly 200 surveys were returned. All three TES system types (ice, water and eutectic salt) are examined.