Capturing carbon with direct ocean capture

A new system would use electrodialysis to remove carbon from sea water for sequestration or use

Spotted: There are many strands to the fight against climate change. One of these is carbon capture – removing carbon from the atmosphere and storing it somewhere, including underground or in building materials. Now there is one more option. Startup Captura, which spun out of the California Institute of Technology, provides low-cost atmospheric carbon removal by removing CO2 from the ocean.

It is well-known that the ocean absorbs CO2 from the atmosphere. However, the increasing amounts of CO2 in the atmosphere are leading to increased absorption and subsequent acidification of the oceans – which is deadly to marine ecosystems.

Captura uses a novel electrodialysis process, powered by renewable energy, to split the salt and water into an acid and an alkali base. The acid is then added to the original flow of ocean water through the plant, triggering a chemical process that draws the CO2 out. The purified carbon dioxide is captured and can then be sequestered or used.

The acidic, decarbonised ocean water is then neutralised by adding back the alkaline base and returned to the ocean. This “decarbonised” seawater sits on the top layer of the ocean and reacts with the atmosphere to draw down more CO2 from the atmosphere, and the process repeats.

The company explains: “We intend to work with partners who will license our technology and build Captura carbon removal plants throughout the world. This will drive the initial deployment of our technology across the utility sector, the desalination industry, and inactive offshore gas/oil platforms. Longer-term, we envisage dedicated Captura platforms similar to today’s ocean-based energy infrastructure.”

There are a number of carbon capture technologies currently in development. Some of the ideas Springwise has spotted include the use of algae, and sequestering carbon by spreading rocks on farmland.

Written By: Lisa Magloff