From Electrons to Formic Acid: Rigorous Process Synthesis and Sustainability Assessment of a Fully Integrated Electrochemical CO ₂ Valorization System

Electrochemical CO 2 conversion emerges as a key area within carbon capture, utilization, and storage (CCUS); however, current research lacks detailed process modeling, especially for downstream separation after electrolysis. To address these gaps, we developed a comprehensive and rigorous modeling framework to evaluate the electrochemical process that converts CO 2 into formic acid. The proposed process integrates CO 2 capture from flue gas, alkaline electrolysis using KOH as the electrolyte, bipolar membrane electrodialysis (BPMED) for ion recovery, azeotropic distillation for product purification, and multi-effect evaporation and crystallization to recover salts as by-products. Initial techno-economic analysis (TEA) and life cycle assessment (LCA) yield a global warming potential (GWP) of 16.87 kg CO 2 -eq and a minimum selling price (MSP) of $6.94/kg, which currently lacks competitiveness against conventional fossil-based benchmarks (GWP = 4.21 kg CO 2 -eq; price = $0.856/kg). Under prospective scenarios powered by solar photovoltaic energy and improved technologies (e.g ., reduced electrolyzer voltage and eliminated BPMED acid crossover), the GWP and MSP drop to 0.94 kg CO 2 eq and $1.393/kg, respectively. Notably, replacing KOH with NaOH further improves these metrics to 0.60 kg CO 2 eq and $1.208/kg. When carbon credits are applied, the adjusted MSPs (e.g., $1.303/kg for NaOH-based scenario) become competitive with the adjusted baseline ($1.525/kg). Additionally, we examined the sensitivity of various LCA midpoint indicators to different allocation strategies. Overall, this rigorous framework enhances the reliability of performance metrics and quantifies the practical potential of electrochemical formic acid production under future industrial scenarios.