The strongest carbon-sequestration method could come from a simple law of chemistry – at least that’s how Captura recently pitched its tech to bring in millions in funding.

Its increased series A round perhaps proves the efficacy of the company’s selling point. After an initial $12 million raised last January, the Pasadena-based venture tacked on another $21.5 million this winter with new industrial investors brought onboard to help commercialize its direct ocean-capture technology.

Captura, which was developed by California Institute of Technology professors CX Xiang and Harry Atwater, aims to scale what is essentially a dialysis mechanism removing carbon dioxide from the ocean to accelerate the ocean’s natural carbon-capturing ability.

Its engineering leverages Henry’s Law, which states that the amount of gas dissolved in a liquid is directly proportional to the amount of gas in the atmosphere directly above.

Captura developed a proprietary electrodialysis process that strips out the carbon dioxide while maintaining the seawater’s natural acidity levels. This allows for ocean water to absorb more atmospheric emissions to obtain an equilibrium, thus adhering to Henry’s Law.

Captura claims its process requires less energy than other direct air-capture technology in development. Since carbon dioxide is 150 times denser in ocean water than in the earth’s atmosphere, the direct ocean capture system churning on docks and in labs can operate with less filtration pull, and thus has less dependence on electricity or other powering mechanisms.

“The ocean is doing all that work for us, and it’s already present at massive scale,” said Steve Oldham, Captura’s chief executive. “If we can find out an effective way to remove that 150-times more concentrated CO2, we’ve suddenly found a great way to enhance the ocean’s power.”

Oldham joined Captura in 2022 after leading Canadian direct air capture company Carbon Engineering for four years. During his tenure there, Oldham secured millions from energy corporations, catalyzing commercialization of carbon sequestration, before the company was ultimately sold to Warren Buffet-backed Occidental Petroleum Corp. last year for $1.1 billion. 

Oldham still believes direct air capture holds a necessary place in the broader carbon emission-cutting effort, but direct ocean capture offers a more frictionless absorbing process.

“All of those things mean inherently you expect your cost to be lower, but also, inherently more capacity to scale,” Oldham said. “I have no supply chain constraints. The ocean already exists.”

A roster of strategic partners
This latest funding round introduced the same capital strategy employed by other capital-dependent carbon capture ventures – the investors included shipping and logistics players that could soon benefit from Captura’s capturing capabilities through carbon removal credits.

Carbon credits are market-based measurements used to commodify the removal of 1 ton of carbon dioxide from the atmosphere. Credits can be bought by companies or individuals to offset their carbon emissions, incentivizing and funding projects that capture carbon dioxide.

Maersk Growth, the venture capital arm of the world’s largest container ship and supply vessel operator in the world, wrote Captura a check. EDP, the largest electricity supplier in Portugal, also participated in the series A round. 

Captura emphasized that these new backers will bring in shipping and logistics, energy and utilities expertise to guide the young company into mass commercialization. The network could come in handy once Captura’s tech can be copied and pasted onto these industries’ structures, such offshore oil platforms and desalination plants.

While carbon removal credits are the key currency in Captura’s industry, the company’s revenue approach differs slightly than that of direct air capture plants because of its partnerships.

The company’s main source of revenue will be licensing its technology and forming joint ventures with partners. It will then sell the carbon dioxide subtraction units to emitting companies. Captura doesn’t want to own the plants running its technology.

On a World War II Navy barge at the Port of Los Angeles, Captura’s largest test system to date hosts a tangle of tanks and pumps that facilitate the reverse engineering of Henry’s Law.

Captura has run its system for more than 200 hours since the facility opened last August. Docked at AltaSea, the public-private ocean institute situated down the road from the historic century-old Warehouse 1, the system hopes to remove 100 tons of carbon dioxide from ocean water by the end of this year.

A vital chemical reaction

Eric Marks, a senior engineer at Captura who works on the testing site, described this as the middle-ground pilot development project in the company’s larger plan. While the system is actively pulling carbon dioxide from seawater, Captura is still finalizing a scalable model at its labs in Pasadena.

“They’re still in their benchtop phase of understanding how they want the parameters of this to work, but when they want to scale up, they’ll be bringing those (systems) here to be installed,” Marks said.

Right now, ocean water isn’t constantly flowing through Captura’s plant. The process runs in batches, splitting a small portion of pumped seawater into one tank holding a strong acid and the other a strong base. The rest of the untreated ocean water will later be introduced to the acidic split-off, igniting a chemical reaction that releases the carbon dioxide.

Using a membrane and vacuum pump, the carbon dioxide is then compressed, while the seawater is reintroduced to the base water to level its pH. Finally, the rebalanced, carbon dioxide-depleted water is returned to the ocean.

Due to its small scale, the company’s barge operation at the Port of Los Angeles currently releases the carbon dioxide it collects from the electrodialysis process. Its larger plants planned, however, have already signed partnerships for carbon dioxide transport and storage.

Last November, Captura announced a partnership with Equinor, a Norwegian energy company, to build a 1,000-ton-per-year pilot plant in Norway by the end of this year. In conjunction with the plant, a Norwegian carbon storage venture called Northern Lights will add to its 1.5-million-ton carbon removal credit goal. 

Earlier last year, Captura also announced it was collaborating with the Canadian carbon management startup Deep Sky to develop a 100-ton system in Quebec.

According to Marks, the Norwegian plant will be highly automated, compared to the current pilot system. 

“We opted for affordability to make it as manual as possible,” Marks said. “When you look around, everything is a valve you have to turn yourself. For the plant that we’re having developed for the end of the year, that’s all automated.”

While Marks will help with Captura’s installation in Norway, the company will continue its research and development at the Port of Los Angeles for the foreseeable future. 

The company has explored the idea of having more plants at the Port of L.A., but it may have to compete for space against other direct air-capture developments at AltaSea.

UCLA’s pilot system, named SeaChange, received $21 million frowm the Chan Zuckerburg Initiative in 2022 and tests on the same barge. The two companies compete not just in their technology’s efficiency, but with feuding investors: Mark Zuckerburg for SeaChange and Elon Musk for Captura, via a grant from his XPrize Foundation. SeaChange doesn’t define itself as direct ocean capture, however, as it introduces calcium carbonate to the returned seawater a byproduct of its process.

According to Oldham, Captura hacks the ocean’s carbon capturing without changing its nature.

“People will say we messed up the atmosphere. We’re not going to mess up the ocean as well and do things to the ocean that maybe we haven’t fully understood,” Oldham said. “We don’t change ocean chemistry. We don’t add anything to the ocean. It’s a different process.”