Optimizing reversible solid oxide cell technology for long-term energy storage in Europe's decarbonized frameworks.

Energy storage is crucial for enhancing energy security. In this study, we explore the indispensable roles of both long-term and short-term energy storage solutions, demonstrating their combined benefits. By achieving 60% round-trip efficiency of long-term storage through reversible solid oxide cells (rSOC) technology, we affirm rSOC's immediate environmental and economic advantages and challenge its perception as merely a future-oriented technology within the current European energy framework. Looking forward to Europe's 2050 energy landscape, our findings indicate substantial variability in storage capacity requirements for various countries, ranging from 54 to 680 kWh/kW for the proposed rSOC system. The use of rSOC as a unique storage technology achieves a minimum levelized cost of storage (LCOS) of 0.88 €/kWh, whereas battery systems reach a lower minimum value of 0.67 €/kWh but exhibit a much broader cost range depending on country and energy context. We demonstrate that hybrid strategies emerge as the most economically viable, reducing costs by up to 78% and, in some cases, to as low as 0.19 €/kWh. These findings support hybrid energy storage strategies as a future-oriented solution.