Abstract The increasing demand for renewable energy integration and scalable power generation highlights the need for efficient and cost-effective solid oxide fuel cell systems. In this study, we present a modular hybrid design framework that enables flexible solid oxide fuel cell scale-up by interconnecting standardized component modules. We introduce a series-parallel configuration that strategically leverages anode and cathode off-gas recirculation to enhance both electrical and thermal efficiency. Through a detailed case study, we demonstrate that the hybrid design achieves 66. 3% electrical efficiency while reducing external water use by 59. 9% and fresh air demand by 22%, outperforming conventional system designs. We further conducted a techno-economic analysis across four scale-up strategies and found that the hybrid design delivers the lowest levelized cost of electricity at 0. 155 /kWh. Through this work, we have highlighted the critical trade-offs between centralization and decentralization, high- and low-technology readiness level technologies, and economies of scale versus manufacturing capacity. We believe our findings underscore the potential of modular and standardized systems to provide scalable, efficient, and economically viable solutions for future low-carbon energy infrastructures.
Wei et al. (2026) studied this question.