Proposal and analysis of an energy storage system integrated hydrogen energy storage and Carnot battery

Abstract

As renewable energy capacity continues to surge, the volatility and intermittency of its generation poses a mismatch between supply and demand when aligned with the fluctuating user load. Consequently, there’s a pressing need for the development of large-scale, high-efficiency, rapid-response, long-duration energy storage system. This study presents a novel integrated energy storage system combining hydrogen energy storage and Carnot battery. Carnot battery serves as the base load for stable, large-scale energy storage, while hydrogen energy storage (PEMEC and SOFC) serves as the regulated load to flexibly absorbs excess renewable electricity and responds promptly to user demand. The integrated system also effectively leverages high-temperature waste from the SOFC to boost Carnot battery’s round-trip efficiency (RTE), enhancing overall system RTE. Energy and exergy analyses are conducted for both the proposed system and a reference system. Results indicate that the proposed system achieves an overall RTE of 57.48% and an RTE of 71.98% for the Carnot Battery, improvements of 5.71% and 11.32%, respectively, compared to the reference system. The mechanisms underlying the efficiency improvements are analyzed, and the impact of capacity allocation between hydrogen storage and the Carnot battery on overall system performance is explored.