Ocean electrodialysis: capturing CO₂ on a massive scale

Let's take it step by step! Climate change is forcing humanity to look for innovative technologies that can remove excess carbon dioxide from the atmosphere. One of the most promising solutions lies not in the air, but in the ocean. Recent research highlights ocean electrodialysis, a groundbreaking method capable of capturing CO₂ on an industrial scale.

What is electrodialysis and how does it work?

Electrodialysis is an electrochemical separation process that uses ion-exchange membranes and an electric field to move ions between solutions. In the case of the ocean, this technology extracts bicarbonate and carbonate ions—the forms in which CO₂ is dissolved—thus effectively removing carbon dioxide from seawater.

The formula in simple terms is:

CO₂ (atmosphere) ⇌ CO₂ (dissolved in seawater) ⇌ HCO₃⁻ + CO₃²⁻

Electrodialysis separates these ions, reducing the concentration of CO₂ in seawater and forcing the ocean to naturally absorb more CO₂ from the atmosphere.

Where is this technology being developed?

Electrodialysis projects are emerging in research centers around the world, including:

The United States (California, Massachusetts) – leading startups in ocean carbon removal.

Germany and Switzerland – strong academic research in electrochemistry and climate technology.

Singapore and Japan – leading test facilities for seawater purification.

Key organizations and companies

Equatic (formerly SeaChange, a division of UCLA): Pioneer in large-scale CO₂ removal from the ocean using electrodialysis.

C-Capture (UK): Research on electrochemical processes for scalable CO₂ capture.

GEOMAR Helmholtz Centre for Ocean Research (Germany): Scientific leader in marine climate solutions.

Notable names:

Prof. Gaurav Sant (UCLA) is one of the leading figures in Equatic research.

Dr. Greg Rau is a researcher known for increasing ocean alkalinity and carbon capture.

A case in point

In Singapore (2023), Equatic launched its first pilot plant capable of capturing 100 kilograms of CO₂ per day directly from seawater. The extracted carbon can then be mineralized into stable solids or reused for industrial purposes.

Costs and economic outlook

Currently, the cost of electrodialysis-based CO₂ capture is estimated to be between $500 and $1,000 per ton of CO₂ removed. However, with scaling up and technological improvements, experts expect costs to fall below $100 per ton, making it competitive with other carbon removal methods.

Expert opinion

Supporters argue that it is one of the most scalable and ocean-safe carbon capture methods.

Skeptics warn about the energy requirements and environmental impact on marine chemistry.

Balanced view: With the integration of renewable energy and rigorous monitoring, electrodialysis could be a game-changer in achieving zero emissions.

Final Thoughts

Ocean electrodialysis is not science fiction, it is a real, working technology with the potential to transform our fight against climate change. By turning the world’s largest carbon sink—the ocean—into an active ally, we can finally capture CO₂ on the scale that humanity desperately needs.

🔗 Read more climate, seas, and ocean breakthroughs on Natural World 50.