Performance Assessment of CSP-SOEC Integrated Hydrogen Production Systems Under Alternative Steam Extraction Methods

Concentrating solar power (CSP) can simultaneously provide high-temperature steam and renewable electricity for solid oxide electrolysis cells (SOECs), offering an efficient pathway for solar hydrogen production. This study proposes and compares two CSP-SOEC integrated hydrogen production configurations based on different steam extraction strategies: main steam extraction before turbine expansion (Scheme 1) and reheated steam extraction after the reheating process (Scheme 2). The effects of steam extraction rate and SOEC operating temperature on the thermodynamic performance of the integrated system are systematically investigated. At an SOEC operating temperature of 600 °C, Scheme 1 achieves a maximum hydrogen production rate of 296.33 g s−1 with an SOEC power consumption of 36.59 MW, while the CSP net output decreases to 1.15 MW. Under the same conditions, Scheme 2 reaches a hydrogen production rate of 240.67 g s−1 and an SOEC power consumption of 29.74 MW, with the CSP net output reduced to 9.37 MW. Increasing the SOEC operating temperature to 1000 °C improves the hydrogen production rates to 271.61 g s−1 and 225.31 g s−1 for Scheme 1 and Scheme 2, respectively. The maximum solar-to-hydrogen energy conversion efficiency reaches 19.5%. For a 50 MW CSP plant, the maximum peak-shaving revenues are 21,002 CNY day−1 for Scheme 1 and 21,350 CNY day−1 for Scheme 2, respectively. The corresponding minimum LCOHs are 40.91 CNY kgH2−1 and 42.36 CNY kgH2−1, respectively.