LCA of electrochemical reduction of CO2 to ethylene

Electrochemical reduction is a promising technology capable of converting CO2 into valuable chemical feedstock. However, the feasibility of transferring small-scale experimental successes to larger scale set-ups calls for careful investigation based on a holistic or system-wide perspective. Electrochemical reduction is a promising technology that is capable of converting CO2 into valuable chemical feedstock. However, the feasibility of bringing reported lab bench successes to industrially relevant scale requires careful assessment from a system-based perspective. This paper presents a unique Life Cycle Assessment (LCA) case study assessing the potential environmental impacts of both smalland largescale set ups of CO2-to-ethylene conversion via electrochemical CO2 reduction reaction (CO2RR). The LCA parameters are modelled according to the current progress of CO2RR from a literature study and an industry standard for CO2 capture and product separation. The output of small scale CO2RR systems are set to 1 g C2H4, while a hypothetical industrial scale is set at 1 ton C2H4 production. Various scenarios taking into account different energy sources to power CO2RR to C2H4 scales are investigated. Apart from the global warming potential (GWP) impacts, other environmental impacts are projected for a more holistic evaluation of CO2RR implementation: acidification potential (AP), eutrophication potential (EP), human toxicity potential (HTP), and photochemical ozone creation potential (POCP). An important message of this study is that the environmental benefits or burdens from small-scale set ups cannot be directly transferred - or linearly projected - to large-scale models. It is also highlighted that along with the focus on GWP reduction, other environmental consequences such as AP, EP, HTP and POCP have to be carefully considered.