Electrochemical Ocean-Based Carbon Capture: Roadblocks to Scale-Up

Electrochemical ocean-based negative emission technologies (EC-ONETs) are emerging strategies that harness the ocean’s capacity for carbon dioxide removal. These systems can couple carbon capture with renewable electricity and water treatment infrastructure and, in the long term, support more ambitious industrial and environmental remediation projects. However, progress─from early demonstrations to deployment at scale─hinges on a more nuanced understanding of electrochemical and transport phenomena in seawater, rigorous field validation, and identification of ecological risks. In this Perspective, we map the current portfolio of EC-ONETs, synthesize reported performance metrics, and outline their limitations and future opportunities. We emphasize the need for a better understanding of pH swing mechanisms and failure modes in seawater, benchmarking standards, biogeochemical impact assessment, coordination with marine sciences, and enhanced public trust through transparent risk assessment and regulatory alignment. We aim to clarify the steps the community can take to advance the practical application of EC-ONETs.