Contributors to output uncertainty in prospective Life Cycle Assessment of emerging artificial photosynthesis technologies

Despite the additional uncertainties inherent in assessing emerging technologies, key contributors to output uncertainty often remain unidentified because uncertainty and sensitivity analyses are not systematically applied in Life Cycle Assessment (LCA). To effectively guide the development of emerging technologies toward improved environmental sustainability performance, it is essential to integrate uncertainty and sensitivity analysis methods that enable the identification of input variables contributing to environmental impact uncertainty. In this study, prospective LCA tools were embedded within a flexible, transparent, and reproducible framework designed to incorporate epistemic uncertainties and support a large number of model runs. The approach is demonstrated using two exemplary CO$_2$-removing artificial photosynthesis product systems, representing an emerging technology at an early stage of development and associated with considerable uncertainties. The results show that, depending on the characteristics of the product system, either scenario- and process-related input variables or system design-related input variables can dominate the output uncertainty. ... mehrThe choice between various climate mitigation pathways exerts a relatively moderate influence on output uncertainty, whereas catalyst materials and their associated production processes have comparatively low influence. The resulting ranges of environmental impacts, when uncertainty is accounted for, can be substantial, challenging straightforward technology ranking. However, identifying the key contributors to output uncertainty provides insights for guiding environmentally oriented technology development. Future work should extend the analysis to additional product systems, broaden the representation of uncertainties, develop heuristics to enhance modeling and computational efficiency, and explore methods to mitigate and communicate uncertainties for decision-making.