Evaluation of biogas-fed solid oxide fuel cell electricity-generation systems: Environmental benefits and sensitivity analysis

The transition from coal-fired power generation to lower-carbon alternatives requires a systematic evaluation of both environmental performance and economic feasibility. In this study, life-cycle assessment and economic analysis were conducted for three electricity generation scenarios: conventional coal-fired power generation, hydrogen-fed solid oxide fuel cells (SOFC), and biogas-fed SOFC. The functional unit was defined as 1000 kWh of electricity generated in North China, and environmental impacts were evaluated using the ReCiPe 2016 midpoint and endpoint methods. The global warming impacts of the coal-fired, hydrogen-fed SOFC, and biogas-fed SOFC scenarios were 1780, 402, and 400 kg CO 2 eq per 1000 kWh, respectively. The biogas-fed SOFC scenario showed lower impacts than coal-fired power generation in most assessed categories, including global warming, fine particulate matter formation, and fossil resource scarcity. However, the SOFC scenarios exhibited higher burdens in several toxicity-related categories and mineral resource scarcity, mainly associated with material and catalyst inputs. Sensitivity analysis showed that changes in biogas composition increased selected environmental impacts by up to 29%, while decreasing the single-cell power from 50 to 40 W increased the global warming impact by 24%. The economic analysis yielded NPV values of −29.40 × 10⁴ and 55.14 × 10 4 US$ for the hydrogen-fed and biogas-fed SOFC systems, respectively. These results indicate that biogas-fed SOFC have potential for lower-carbon electricity generation, although catalyst use, cell performance, system boundaries, and economic assumptions remain critical for their environmental and commercial viability.