Renewable-powered high-temperature compressed air energy storage to accelerate grid decarbonization

Long-duration energy storage (LDES) is vital for power system decarbonization, but existing technologies, such as adiabatic compressed air energy storage (A-CAES), face flexibility and efficiency constraints. We report a novel high-temperature compressed air energy storage (Hi-CAES) concept utilizing clean external heat sources, such as curtailed renewable electricity and hydrogen. By decoupling heat input from compression, Hi-CAES enhances expansion temperatures and dispatchability compared with conventional A-CAES. Techno-economic and thermodynamic analyses demonstrate competitive round-trip efficiency and significantly lower carbon intensity than grid-based charging. Under IPCC-aligned scenarios, Hi-CAES reduces life-cycle emissions to 2.51 gCO 2 ·kWh −1 by 2050, compared with 145.95 gCO 2 ·kWh −1 for state-of-the-art CAES. With lower electricity costs in certain configurations, Hi-CAES provides a scalable, economically viable solution for long-duration storage and urgent transitional emission mitigation, accelerating deep grid decarbonization.