Exploring intra-regional hydrogen production alternatives for fuel cell vehicles via greenhouse gas-based life cycle supply chain (GHG-LCSC) optimization

Hydrogen power and electric vehicle rollout are among the global mitigation efforts for net-zero emission targets. Hydrogen fuel cell vehicle (HFCV) is a promising embodiment of these two climate-neutral levers. Nevertheless, insufficient investigation of the life cycle of hydrogen production pathways and supply-demand mismatching jeopardize the optimal implementation of HFCV. A novel integrated framework combining life cycle greenhouse gas assessment and intra-regional supply-demand optimization method is developed to (1) evaluate the emissions performance for six typical HFCV hydrogen production pathways and (2) map out the optimal intra-regional hydrogen supply-demand allocation based on the trade-off between resource flow and geographical proximity. As one of the world's largest HFCV producers and consumers, China is chosen as the case study. The life cycle emissions assessment reveals that the Natural Gas Steam Methane Reforming (NG_SMR) pathway emits the most greenhouse gas (GHG) emissions (i.e., 0.215 g CO 2 -eq/kJ H 2 ) while the Clean Energy_Water Electrolysis (CE_WE) pathway emits the least GHG emissions (i.e., 0.02 g CO 2 -eq/kJ H 2 ), stretching a 10-times emission difference. For intra-regional supply-demand optimization, provinces like Shaanxi, Shanxi, and Shandong act as the main suppliers (>50% of the total hydrogen source in China) to provinces like Guangdong, Zhejiang, and Sichuan, suggesting a north-to-south (N-S) regional hydrogen transmission. A sensitivity analysis is conducted based on the variation in production efficiency among different hydrogen production technologies in the HFCV value chain. The results inferred that the Coal Gasification & Carbon Capture and Storage (C l G & CCS) and CE_WE pathways are insensitive to efficiency improvement. In the scenario analysis, the outcome suggested urgently phasing out grey hydrogen pathways and accelerating the transition of grey-to-green hydrogen production pathways with the buffering of blue hydrogen pathways between 2015 and 2040 for the net-zero emission ambition by 2060. This study enlightens the decision-makers to endorse green hydrogen production for HFCV while securing hydrogen energy security.