Pumped Thermal Energy Storage (PTES) is a technology that utilizes heat pumps and thermal energy storage (TES) to store electricity as thermal energy. During periods of low electricity demand or high renewable energy generation, electricity is used to power a heat pump, which generates heat and stores it in a TES system. When electricity is needed, the stored heat is used to drive a heat engine, generating electricity.
PTES technology is still in the early stages of commercial deployment, with a limited number of pilot projects and demonstration plants in operation. However, the technology is gaining increasing interest as a potential solution for long-duration energy storage and grid-scale applications.