Modeling, Optimization, and Techno-Economic Analysis of Bipolar Membrane Electrodialysis for Direct Air Capture Processes

Bipolar membrane electrodialysis (BPMED) could allow for the complete electrification of direct air capture (DAC) technologies. In this work, we have modeled and optimized two DAC processes based on different electrodialysis cell designs. The technical assessment has been complemented by a detailed economic analysis, showing the advantages but also the current shortcomings of this technology and pathways for advancement. A minimum energy demand of 24 MJ kg(CO2)(-1) has been estimated for the base-case scenario, a result comparable to what has been reported for other liquid-scrubbing DAC technologies. Several solutions to further abate power consumption have been reviewed, with the most promising case providing a 29% reduction. Membrane cost and performance are currently the main limiting factors. In a scenario where cheaper membranes with better performance are assumed to be available, total costs below $250 ton(CO2)(-1) may be feasible, making BPMED a viable fully electrified alternative to other technologies requiring natural gas.