Direct stack heating and model predictive control for safe load-following of solid oxide electrolysis cells

Thermal management is essential for safe load-following of solid oxide electrolysis cells (SOECs) under fluctuating renewable power. This study develops and validates a one-dimensional dynamic model of an anode-supported co-flow planar SOEC under steady-state and transient conditions. The maximum RMSE values for cell voltage and temperature are 0.02 V and 2.3 °C, respectively. Based on this model, regime-specific thermal management strategies are proposed. For endothermic operation, direct stack heating using embedded electric heaters is compared with PI-based air-flow control and achieves temperature regulation with a lower thermal gradient. For exothermic operation, a multi-input multi-output model predictive control strategy coordinates anode and cathode flow rates while constraining thermal gradients within safe limits. The proposed strategies are further evaluated under fluctuating renewable load profiles, demonstrating effective temperature regulation and safe thermal-gradient control for flexible SOEC operation.