Pumped heat energy storage designed to bolster grid stability

November 16 -- A pumped heat thermal energy storage (PTES) demonstration facility has been constructed and operated by the Southwest Research Institute. Developed in collaboration with Malta Inc. and with funding support from the U.S. Department of Energy, this long-duration, large-scale energy storage technology is engineered to help balance energy volatility and reliability issues associated with solar and wind energy facilities.

The PTES system stores energy thermally in hot and cold tanks for later use. A heat pump is activated to render the hot storage tank hotter and the cold storage tank colder during periods of excess renewable

Long-duration, large-scale storage capabilities afforded by PTES can help balance energy volatility and reliability issues associated with renewable energy resources. Source: Malta Inc. energy production. The system functions as a heat engine when energy demand surpasses production, converting the large temperature difference between the hot and cold stored energy into electricity. Simple recuperated cycles are used for both modes of operation with air as the main working fluid.

A full-scale PTES system offers high potential system performance up to 60% round-trip efficiency and can store energy for more than 10 hours, according to the researchers. Malta Inc. is now developing a full-scale commercial PTES system capable of storing energy for longer durations.