Feasibility and Prospects of Electrocatalytic Conversion of CO2 for Chemical Feedstock Production and Renewable Energy Storage

Electrocatalytic CO2 reduction (ECO2R) powered by low-carbon electricity presents a promising pathway toward achieving carbon neutrality and environmental sustainability, as it converts large amounts of CO2 into chemical feedstocks and storable fuels. Based on current state-of-the-art laboratory techniques and optimistic scenario assumptions, systematic techno-economic and life cycle assessments of ECO2R are performed to predict its industrial viability and prospects, particularly in renewable energy storage. The analysis extends from lab-scale to industrial-scale using material flow and energy balances. The energy consumption, energy efficiency, production costs, and life cycle impacts of ECO2R to different target products are analyzed and compared. The techno-economic and environmental benefits of ECO2R with different products as energy carriers for storing renewable energy are discussed and compared with hydrogen production via PEM water electrolysis as energy storage schemes, to assess the feasibility and potential of ECO2R in large-scale, long-term renewable energy storage. The results reveal that energy efficiency is a critical constraint that limits the commercial viability and environmental benefits, as electricity costs account for 45–70% of production expenses and over 90% of greenhouse gas emissions stem from electricity consumption. The emission factor of the supplied electricity for ECO2R at zero emission scenarios is evaluated; among the target products, the carbon intensity of the supplied electricity for ECO2R to ethylene is allowed to be as high as 0.26 kg CO2-eq/kWh. As a sustainable energy storage solution, while ECO2R is less energy-efficient than producing hydrogen by PEM electrolysis of water, it offers greater potential in economic and carbon reduction.