Sustainable conversion of carbon dioxide (CO<
sub>
2<
/sub>
) to value-added chemicals or fuels shifts a linear ?cradle to grave chemicals or fuels manufacturing model? to a circular carbon economy. A key consideration for CO<
sub>
2<
/sub>
utilization is the economic viability of converting specific CO<
sub>
2<
/sub>
sources based on scale, purity, etc. Among different CO<
sub>
2<
/sub>
sources, the corn dry mill ethanol plant with onsite waste CO<
sub>
2<
/sub>
upgrading is considered as a low hanging fruit strategy for implementing CO<
sub>
2<
/sub>
utilization with minimum requirements for gas purification. This study investigates the detailed techno-economic analysis of using a hybrid bio-electrochemical process to convert waste CO<
sub>
2<
/sub>
streams from corn dry mill facilities into ethanol and demonstrates the impact of CO<
sub>
2<
/sub>
utilization on the biorefinery economics. The bio-electrochemical CO<
sub>
2<
/sub>
conversion process combines water electrolysis to hydrogen (H<
sub>
2<
/sub>
), electrolysis of CO<
sub>
2<
/sub>
-to-carbon monoxide (CO), and gas fermentation to ethanol. With onsite CO<
sub>
2<
/sub>
conversion, total ethanol yield can be potentially improved by 45%. In this study, variations of H<
sub>
2<
/sub>
:CO ratio ranging from 0 to 5 are explored to understand the impact of gas mixture composition on economic viability. The techno-economic analysis results show single-pass carbon yield in the biological conversion step can be potentially improved up to 100% when using H<
sub>
2<
/sub>
as an alternative energy source. Upgrading waste CO<
sub>
2<
/sub>
generated from a corn dry mill facility via biological CO<
sub>
2<
/sub>
to ethanol conversion is likely to be cost effective under the following conditions: high CO<
sub>
2<
/sub>
electrolysis energy efficiency (=70% theoretical), low electricity cost (=$0.02/kWh), and high CO<
sub>
2<
/sub>
electrolysis conversion efficiency (=50% CO<
sub>
2<
/sub>
input).