A technical and economic analysis of three cool storage configurations using ice or clathrates is presented. Results of this analysis show that a direct contact system with a 6 degree C clathrate is the most energy efficient of the storage systems analyzed. The economic viability of cool thermal energy storage TES systems is directly related to the cooling load that can be shifted. However, to break even with a simple air conditioning system, a nonpressurized storage medium is found to be a requirement for cool storage systems.