Prospective Life Cycle Assessment of Early‐Stage CO 2 ‐Removing Artificial Photosynthesis Producing Synthesis Gas, Hydrogen Peroxide, and Methane

Due to the urgent need to mitigate the consequences of climate change, emerging technologies such as artificial photosynthesis could be crucial. To enable an environmental sustainability assessment of this early‐stage technology, recent methods in prospective Life Cycle Assessment are applied and extended with break‐even sensitivity analysis to evaluate the minimum requirements of the technical parameters as well as Monte Carlo simulations to include uncertainties in the model. This study focuses on two CO 2 ‐removal technologies based on artificial photosynthesis: photocatalytic carbon dioxide reduction for producing synthesis gas (H 2 +CO) and photoelectrochemical carbon dioxide reduction for producing hydrogen peroxide and methane (H 2 O 2 &CH 4 ). The results indicate that while artificial photosynthesis could be environmentally beneficial, it is highly dependent on the scenarios used in the prospective background database and system design parameters, both of which can alter the technology ranking. While prospective Life Cycle Assessment incorporating break‐even sensitivity analysis and uncertainty analysis can guide technology development by identifying minimum parameter requirements and theoretical competitiveness, these analyses can significantly affect the outcomes by producing a wide range of results, making interpretation challenging. Thus, these analyses are crucial and highlight the need for further research, particularly to improve result interpretation and communication.