<p>Development
of electrochemical pathways to convert CO<sub>2</sub> into fuels and feedstock is
rapidly progressing over the past decade. Here we present a comparative
cradle-to-gate life cycle assessment (LCA) of one and two-step electrochemical conversion
of CO<sub>2 </sub>to eight major value-added products; wherein we consider CO<sub>2</sub>
capture, conversion and product separation in our process model. We measure the
carbon intensity (i.e., global warming impact) of one and two-step electrochemical
routes with its counterparts – thermochemical CO<sub>2</sub> utilization and
fossil-fuel based conventional synthesis routes for those same products. Despite
inevitable carbonate formation in one-step CO<sub>2</sub> electrolysis, this analysis reveals one-step electrosynthesis
would be equally compelling (through the lens of climate benefits) as compared
to two-step route. This analysis further reveals that the carbon
intensity of electrosynthesis products is due to significant energy requirement
for the conversion (70-80% for gas products) and product separation (40-85% for
liquid products) phases. Electrochemical route is highly sensitive to the
electricity emission factor and is compelling only when coupled with
electricity with low emission intensity (<0.25 kg CO<sub>2</sub>e/kWh). As
the technology advances, we identify the near-term products that would provide
climate benefits over fossil-based routes, including syngas, ethylene and n-propanol.
We further identify technological goals required for electrochemical route to
be competitive, notably achieving liquid product concentration >20 wt%. It
is our hope that this analysis will guide the CO<sub>2</sub> electrosynthesis
community to target achieving these technological goals, such that when coupled
with low-carbon electricity, electrochemical route would bring climate benefits
in near future. </p>
Process Design Guided by Life Cycle Assessment to Reduce Greenhouse Gas-Related Environmental Impacts of Food Processing