Guiding research in electrochemical CO2 conversion strategies through a systems-level perspective

Abstract

Carbon conversion technologies are gaining interest as a solution to utilize captured CO₂ and contribute to efforts to reduce greenhouse gas emissions. This work provides technology developers with a systems-level perspective of the climate impacts of electrochemical CO₂ conversion products. Different uses (polymer production, transportation fuels, and power generation) of three CO₂-based fuels (methane, methanol, and diesel) are compared considering different combinations of electrolyzers (water or CO₂ electrolysis) and thermochemical methods. Additionally, the influence of assumptions and trade-offs between environmental and economic performance are evaluated in sensitivity analyses, using polymer and diesel production as examples. Finally, recommendations are provided based on environmental and economic analyses. The novelty of this work involves the application and communication of LCA methods and insights aimed at helping developers visualize their technology in the full supply chain, providing examples of analyzed systems and a set of recommendations that can be generalized and incorporated into the development of different technologies. Example recommendations include considering that in projects focusing on improving the environmental performance of electrochemical processes, cell degradation and electricity source are major factors. On the other hand, for economic performance, lifetime is more important than cell degradation and electricity source. Electrochemical processes are quite promising from a climate change perspective if the input electricity is from a low-carbon source, if the use phase does not involve combustion, if the product is efficient for the use chosen (e.g., diesel is more efficient for transportation than other fuels), and if the use has a large market size.