Synthetic natural gas (SNG) production from captured CO₂ and H₂ produced by water electrolysis using renewable energy is of increasing interest for low-carbon fuel production, CO₂ utilization technology, and unstable renewable energy storage. In this study, the effect of voltage degradation in a water electrolyzer, a core technology for SNG production, on the unit production cost of SNG production and CO₂ emissions, with different water electrolysis types such as alkaline electrolysis (AEL), proton exchange membrane electrolysis (PEMEL), and solid oxide electrolysis (SOEL), was identified through techno-economic and environmental assessment. In particular, the energy efficiency, unit production cost of SNG, and CO₂ emissions were identified based on the change in the power consumption caused by voltage degradation. Moderate voltage loss results in a decrease in energy efficiency from 53.8% to 48.8% in AEL, 55.3% to 47.0% in PEMEL, and 76.3% to 51.2% in SOEL. Moreover, respective SNG unit production costs of 140.3–170.2 USD MWh⁻¹, 157.5–203.1 USD MWh⁻¹, and 153.1–353.5 USD MWh⁻¹ for AEL, PEMEL, and SOEL, respectively, were obtained, showing an increase in SNG production cost due to the voltage degradation. Furthermore, total CO₂ emissions for the SNG production process were investigated considering voltage degradation as well as electricity generation sources.

使用可再生能源通过水电解产生的捕获的 CO ₂和 H ₂生产合成天然气 (SNG) 在低碳燃料生产、CO ₂利用技术和不稳定的可再生能源存储方面越来越受到关注。在本研究中，使用碱性电解 (AEL)、质子交换膜等不同水电解类型，作为SNG 生产核心技术的水电解槽中的电压退化对 SNG 生产的单位生产成本和 CO ₂排放的影响通过技术经济和环境评估确定电解（PEMEL）和固体氧化物电解（SOEL）。特别是能源效率、SNG 的单位生产成本和 CO ₂排放是根据电压下降引起的功耗变化来确定的。适度的电压损失导致能量效率从 AEL 的 53.8% 降至 48.8%、PEMEL 的 55.3% 至 47.0% 和 SOEL 的 76.3% 至 51.2%。此外，AEL、PEMEL 和 SOEL 分别获得了 140.3-170.2 美元 MWh ^-1、157.5-203.1 美元 MWh ^-1和 153.1-353.5 美元 MWh ^{-1 的}SNG 单位生产成本，显示 SNG 增加因电压劣化导致的生产成本。此外，考虑到电压退化和发电源，研究了 SNG 生产过程的CO ₂总排放量。