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THERMAL ENERGY STORAGE

Unlike renewable energy, thermal energy storage (TES) does not produce electricity. Rather, it shifts the time when electricity is demanded for purposes such as air-conditioning. The primary benefit of TES is its peak shifting technology, making it a potentially very valuable tool in the future. In the utility business, this is a very important concept, as it can be expensive for utilities to either produce or purchase energy to serve the highest peak demands (i.e. Redding's hot summer afternoons). In order to shift demand, energy must be stored for use at a later time. Thermal energy storage utilizes a storage mass (usually in the form of ice) to contain cold energy to be released when needed.  Other benefits of TES include the extended lifecycle of the cooling systems, the ability to reduce carbon emissions by shifting from on-peak to off-peak energy demands, and overall air-conditioning efficiency improvements.

The most common types of TES systems utilize a tank (or tanks) to store either ice or chilled water. In order to chill the water used in the process, a standard chiller or A/C condensing unit is operated at night to produce ice and charge the tank. This shifts the demand from the chiller or A/C unit to the off-peak time period. Thus, when air-conditioning is needed in the day, the chilled water undergoes a controlled release from the tank and acts as a refrigerant to cool the air. Some applications will install enough storage to cover the cooling needs of the entire day, while others will install a partial coverage system. The level of cooling capacity installed is dependent upon several variables including installation costs, cost of power, and space availability.

As a customer, you may be asking yourself "How do I benefit from Thermal Energy Storage?" Please click on the link for a more in-depth review of how the customer, the utility, and the environment all benefit from TES and peak-shifting technology. For more information please email Bryan Cope

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