ABSTRACT A reversible solid oxide cell (ReSOC)‐based electrical energy storage system (EESS) for balancing daily energy demand at utility scale is proposed. The GWh‐scale EESS is designed for operation with one long continuous charging step per day followed by mode reversal and another longer continuous discharge step, terminating with a mode‐reversal to charging mode. The novel features of the EESS are modular construction of solid oxide cell system and balance‐of‐the plant (BoP), where ReSOC operates at 20 bar and 650°C in both modes, compressed storage of hydrogen and oxygen in type I storage systems in gaseous state, autothermal operation in both modes using a balance of plant (BoP) that includes an afterburner and a Rankine‐cycle based auxiliary power generation system that eliminates the need for thermal energy storage. Detailed sizing and layout study shows that the total floor area required for the system is 14.1 m 2 /MWh, which makes it compact enough to compete with conventional battery systems. Estimations of capital cost and levelized cost of energy storage show these to be comparable to those of other battery storage systems.
Muhammed et al. (Sun,) studied this question.