Environmental impact analysis for manufacturing 200 kW SOFC and PAFC systems via life cycle assessment

The fuel cells of the future for sustainable development are solid oxide fuel cell (SOFCs) and phosphoric acid fuel cell (PAFCs), and they will have to coexist as future energy sources. This requires a proper understanding of the properties of the materials used in both fuel cell systems and the ability to identify and mitigate the challenges associated with materials that have a high environmental impact. In this study, all materials and processes involved in the manufacturing of 200 kW SOFC and PAFC systems for power generation are divided into stack, balance of plant (BOP) and system assembling components, and a cradle-to-gate environmental impact assessment is conducted to assess the life cycle process from raw materials extraction to final system manufacturing. A whole-system environmental impact assessment showed that the environmental impact of a PAFC system was 7.4 (terrestrial ecotoxicity) to 140 times (human carcinogenic toxicity) higher than that of a SOFC due to the dominant impact of the Pt catalyst used in the fuel cell electrode and reformer in the system. Furthermore, the environmental impact potential of the SOFC stack material and the specific BOP components of both fuel cells are significant. From an environmental perspective, PAFCs are suitable when using pure hydrogen, while SOFCs have an environmental advantage when a reforming system is applied. Improvement measures for environmental impact hotspots and limitations derived from the LCA results are presented.