Pumped Thermal Energy Storage for Multi-Energy Systems Optimization

Abstract

Grid-scale energy storage systems are essential to support renewables integration and ensure grid flexibility simultaneously. As an alternative to electrochemical batteries, Pumped Thermal Energy Storage is a new storage technology suitable for grid-scale applications. This device stores electric energy as thermal exergy, which can be discharged directly for thermal uses or converted back into power depending on the necessities of the grid. The capability of the proposed energy storage to act as electric and thermal storage fits with the sector coupling necessities of multi-energy systems in which electrical and thermal energy carriers are involved. This paper investigates the effects on optimal grid management of integrating a Brayton Pumped Thermal Energy Storage into a multi-energy system. The case study includes renewable generation from photovoltaic modules and residential and industrial users' electrical and thermal load profiles. The system day-ahead optimization, performed through a Mixed Integer Linear Programming approach, aims to minimize the operational cost computed over a 24-hour horizon. The simulation highlights how the proposed storage technology interacts with the users' requirements during different seasons. The final results highlight that using multi-energy storage (i.e., providing power, heating, and cooling) brings a 5% reduction in operating costs during the year compared to a traditional electric-to-electric storage operation.