Energy Storage and Time-of-Day Rate Structures

In order to be cost effective, utilization of time-of-day electric rates must entail energy storage. Storage of heat as hot water or cooling as ice on a 24 hour daily cycle or on a 168 hour weekly cycle can bring an economic return on the additional investment. In the absence of time~of-day, energy storage can be cost effective in several areas of the country by using a heat pump to heat a building in the winter by using the freezing of ice as the source of heat. Storage of the ice made in the winter to air condition the building in the summer can provide a coefficient of performance greater than 2.8 on an annual basis