Technology

Captura facility could remove gigatons of carbon dioxide from the ocean

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Rendering of a large-scale Captura facility that captures carbon dioxide from ocean water
Captura Corporation
Rendering of a large-scale Captura facility that captures carbon dioxide from ocean water
Captura Corporation
Infographic of Captura's Direct Ocean Capture technology
Captura Corporation
Captura's 100-ton Direct Ocean Capture pilot system in the lab at Pasadena
Captura Corporation
The DOC technology has been developed at Caltech and is capable of extracting gigatons of carbon from the ocean

Captura Corporation
The company aims to achieve large-scale carbon removal at a lower cost without using purpose-built air contactors

Captura Corporation
Captura first Direct Ocean Capture pilot system at Newport Beach, California
Captura Corporation
The company intends to extract carbon dioxide from ocean water using only renewable electricity and ocean water as inputs to minimize the environmental impact

Captura Corporation
Captura set up its first ocean-based pilot facility as a stand-alone unit in Newport Beach, California
Captura Corporation
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Captura Corporation, a spinoff of the California Institute of Technology, has developed a revolutionary plan to remove carbon emissions by creating an aquatic purification facility in the middle of the sea. The company intends to extract carbon dioxide from ocean water and release the purified water back into the ocean, using only renewable electricity and ocean water as inputs to minimize the environmental impact.

The carbon clean-up will be achieved through the company's patented electrodialysis process, dubbed Direct Ocean Capture (DOC). DOC generates a stream of pure CO2 that can be sequestered or reused to produce other low-carbon materials or products, in an effort to mitigate the adverse effects of climate change. The company aims to achieve large-scale carbon removal at a lower cost than existing methods.

The Caltech-developed DOC technology is reportedly capable of extracting gigatons of carbon from the ocean. The process begins by bringing a filtered stream of ocean water into the facility, where the electrodialysis technology is used to create acid.

This acid is then added to the ocean water, triggering a chemical reaction that extracts CO2 from the water. The process is accelerated using a gas-liquid contactor and vacuum pump, resulting in a purified stream of carbon dioxide that can be reused or sequestered.

Infographic of Captura's Direct Ocean Capture technology
Captura Corporation

"Less than 1% of this water is diverted and pre-processed to purify the ocean water into pure salt water," says Captura. "This salt water is then processed in Captura’s proprietary electrodialysis technology. Through dissociation, electrodialysis uses renewable electricity to split the salt and water into an acid and an alkali base."

The process of neutralizing ocean water flow is done by adding an alkaline base. This helps in absorbing atmospheric carbon dioxide, after which the decarbonized water is returned to the ocean. According to Captura, this water can then react with the atmosphere to draw down an equivalent quantity of CO2. After being filtered, seawater has the remarkable capacity to reabsorb the same amount of CO2 from the atmosphere that was initially removed. This unique capability makes it an effective tool for mitigating the effects of climate change.

"This decarbonized water then sits in the top layer of the ocean and will then react with the atmosphere to draw down an equivalent quantity of CO2," states Captura.

In 2022, Captura set up its first ocean-based pilot facility as a stand-alone unit in Newport Beach, California. The company used a continuous flow of ocean water to measure system performance and make necessary improvements.

Captura's 100-ton Direct Ocean Capture pilot system in the lab at Pasadena
Captura Corporation

Following on from the success of the pilot trials, Captura (in collaboration with AltaSea at the Port of Los Angeles), plans to set up its second direct ocean capture system that can cleanse 100 tons (90.7 tonnes) of carbon dioxide from the ocean each year. To advance the technology, Captura will be conducting ocean modeling and technology development, with the goal to further validate, scale, and enhance its innovative processes.

"Captura’s technology is progressing rapidly through our piloting program towards large-scale commercial deployment," said Captura CEO Steve Oldham. "Now, our work with AltaSea means we can further accelerate our technology and monitor how our system interacts with the ocean, and we couldn’t think of a better partner to help us take our progress to the next level. Alongside the support from SoCalGas, this really is a great example of California companies working together to take a leading role in the fight against climate change."

Source: Captura Corporation

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26 comments
Jimmy the Geek
So as always, the other half of the equation, then what to do with the CO2. Is there a large enough demand / market? What are the logistics and economics of transporting to where it is subsequently dealt with? Are there options for onsite conversion to an environmentally useful product such as solidifying, stabilizing and sealing to drop right back in the ocean to create reefs?
paul314
If I understand it, this relies on the idea that all the carbon dioxide extracted from the ocean will be permanently kept out of the atmosphere, and that the seawater will promptly re-absorb as much carbon dioxide as it held before. If both of those don't happen, this project could make things worse.
Trylon
Sounds impressive. I would be skeptical if not for their CalTech bona fides. I'd be willing to invest if they go public.
Speedy
Where’s the scaling plan from 100 tons per year to Gigaton level mentioned in the title. Infinite tech capability still needs a cost feasible development plan
Needmoredata
So what happens to the CO2 in the capture process? Second where in the ocean would they put this rig? Cool tech though, if it is ever built.
Sean1313
I was surprised not to see an expected price to remove a Tonne of CO2, as i wondered how this would stack up to direct extraction from air. I thought from water might be more effective, but i guess only if the concentration of CO2 was higher than in air.

i like the idea of dropping it back in the ocean to make reefs, just need a calcium source (also in sea water) to convert to calcium carbonate (what reefs are made of).

I wonder if disused oil rigs could be converted to use as the base to save on construction costs.
paleochocolate
What are we using the CO2 for?
David F
What about the effect on phytoplankton? They obtain their CO2 from the water. As they form the base of the marine food chain, what will be the broader consequence to the marine ecosystem of such interference?
Claudio
I'm sure that all those solar panels won't have any problems in a humid and saline environment, nor with sea waves washing them in bad weather... no, wait...
;-)
michael_dowling
Just a thought. You could use the captured CO2 to grow algae in large,covered ponds-algae is among the fastest growing plants. The algae in turn could be dried and buried to keep the carbon out of circulation for centuries.