Techno-Economic and Life Cycle Assessment of Biogas-to-Hydrogen Production: Comparison of Pre-Reforming Decarbonization and Direct Reforming Routes

Biogas-to-hydrogen production provides a renewable pathway to decarbonize hydrogen supply, yet consensus remains lacking regarding the most energetically and economically favorable process configuration. This study develops steady-state Aspen Plus models for two 40,000 Nm3·d−1 biogas-to-hydrogen routes—pre-reforming decarbonization (Process A) and direct reforming (Process B)—and conducts a comprehensive evaluation across technical, economic, and environmental dimensions through combined techno-economic analysis (TEA) and life cycle assessment (LCA). Process B achieves a 7.8% higher hydrogen yield of 0.152 kg H2 per Nm3 of biogas compared with Process A (0.141 kg·Nm−3), but consumes 9.9% more electricity per kilogram of hydrogen (14.37 vs. 13.08 kWh·kg−1). Under baseline prices (0.6 CNY kWh−1 electricity, 1.2 CNY Nm−3 biogas), Process B delivers a slightly lower net levelized cost of hydrogen (LCOH) of 16.21 CNY kg−1 (2.25 USD kg−1), compared with 16.63 CNY kg−1 (2.31 USD kg−1) for Process A. The economic break-even electricity price between the two routes is approximately 0.93 CNY kWh−1. Environmentally, Process B yields a lower baseline 100-year global warming potential (GWP100) of 8.34 kg CO2-eq kg−1 H2 under the national grid mix, as methane slip from the pre-reforming PSA unit in Process A more than offsets the emission savings from lower electricity consumption. Under prevailing industrial electricity tariffs in China, direct reforming presents a slight overall competitive advantage, while pre-reforming decarbonization is more suitable for regions with high electricity prices.