Comparative life cycle and economic assessments of various value-added chemicals' production via electrochemical CO2 reduction

Electrochemical CO2 reduction integrated with renewable electricity has been regarded as a promising approach for reducing CO2 emissions and producing value-added chemicals. However, the technical and economic benefits of C1- and C2-chemical production via electrolysis are still ambiguous, especially when performed in flow cells. In this study, life cycle and economic assessments are conducted to evaluate the energy impacts, environmental impacts, and economic benefits of various value-added chemicals (C1- and C2-) via electrochemical CO2 reduction based on flow cells. The results show that C2-chemical production has more positive energy impacts but more negative environmental impacts than C1-chemical production. C2H4 production has the lowest net energy ratio (NER) (1.19), followed by CH4 (1.56), C2H5OH (1.80), HCOOH (3.01), and CO (3.77). In contrast, the greenhouse gas (GHG) emissions of C1-chemicals (CO: −0.6078 and HCOOH: −0.6130 t CO2-eq. per (t CO2 gas injection)) are the lowest. Besides, sensitivity analysis indicates that the NER and GHG emissions are mainly affected by cell voltage (Ecell), followed by the single-pass conversion (SPC) of CO2 and faradaic efficiency (FE). Moreover, economic assessments demonstrate that C2-chemicals have a higher net present value (NPV) but a longer payback time than C1-chemicals. Economic sensitivity analysis shows that reducing the electricity price and Ecell, as well as increasing FE, are effective pathways to promote the industrialization of this technology. This work provides a direction to promote the technical and economic benefits of electrochemical CO2 reduction via flow cells.