Efficient, affordable, carbon-neutral power: Advanced solid oxide fuel cell-electrolyzer system

The alarming increase in atmospheric carbon dioxide levels, primarily attributed to human-induced fossil fuel combustion for power generation, underscores the urgency for sustainable solutions. The solid oxide fuel cell (SOFC) is a promising candidate for clean power and heat production. This study introduces an innovative system integrating SOFC with solid oxide electrolyzer cells (SOEC) to enhance CO2 capture. Traditionally, the SOFC system converts about 85% of the fuel into electricity, with any unconverted fuel undergoing combustion, yielding water and CO2. In this study, an enhanced SOFC system equipped with various CO2 capture technologies has been evaluated, including post-combustion capture through amine absorption and membrane separation and burner oxy-combustion with pressure swing adsorption for air-to-oxygen separation, combined with SOEC for oxygen production from water and CO2. Criteria such as efficiency, costs, CO2 capture rate, and purity have been used for evaluation. Notably, the innovative SOFC-SOEC configuration achieves 100% CO2 capture rate and purity. While the efficiencies of different integrated SOFC systems are comparable, membrane separation exhibits lower CO2 capture rates, pressure swing adsorption results in decreased purity, and amine absorption requires a more substantial investment. Interestingly, the active area required for the SOEC is a mere 1.3% of the SOFC active area. The novel SOFC-SOEC system has proven to be a compact, long-term, and cost-effective solution, showing significant potential in advancing the transition towards cleaner and more sustainable power generation.