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

Abstract

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 CO_2-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 (E_cell), 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 E_cell, 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.