Life cycle assessment on the role of H₂S-based hydrogen via H₂S-methane reforming for the production of sustainable fuels

Meeting current decarbonization targets requires a shift to a hydrogen energy nexus, yet, water is a valuable resource for hydrogen production, shifting the perspective to the use of H₂S instead within the context of circular economy. A comprehensive understanding of the environmental impacts, using a cradle-to-gate life cycle assessment (LCA), was developed focusing on the operation of hydrogen sulfide-methane reforming (H₂SMR) for H₂ production benchmarked to conventional technologies, steam methane reforming (SMR) and SMR + carbon capture (CC), as feedstock to produce sustainable fuels (i.e., methanol and ammonia). The environmental impact of the different application routes was evaluated in terms of normalized impact categories and monetized indicators by calculating the environmental damage cost. The results indicated that the environmental impact increased when moving from H₂SMR < SMR + CC < SMR, and ammonia compared to methanol production. Across all the processing schemes, the impact on human health is the largest based on the normalized values, representing 63.0–85.0 % of endpoint level impacts. Within the scope of climate change, the use of H₂SMR is indeed more supportive of climate mitigation efforts, reducing environmental costs related to GWP by 58.0 % from SMR and 12.0 % from SMR + CC. Addressing these concerns demands a comprehensive overhaul of existing practices within the oil and gas sector concerning raw material extraction, coupled with the implementation of effective waste management strategies to significantly minimize adverse environmental effects.