Startups Turn to the Oceans to Capture Carbon: A Spotlight on Innovators

The battle against climate change has sparked innovation in unexpected realms, and Earth’s oceans have become a key focus for companies seeking to curb carbon emissions.

Among these trailblazers, startups like Captura, Ebb Carbon, and Equatic are pioneering technologies that leverage the ocean's natural ability to absorb and store carbon dioxide.

These companies aim to transform the seas into efficient carbon sinks while navigating the complexities of scalability, environmental safety, and economic feasibility.

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Captura operates a pilot plant on a barge docked at the Port of Los Angeles.

Harnessing the Ocean’s Power: The Innovators Behind the Movement

Captura: Electrochemically Capturing CO2 From Oceans

At the forefront of ocean-based carbon capture is Captura, a marine-tech startup operating out of Pasadena, California.

Their technology employs a process called electrodialysis to remove carbon dioxide from seawater.

Using renewable energy, their system separates seawater into acid and base streams, chemically reacting with dissolved carbon to extract CO2 before safely returning the treated water to the ocean.

Steve Oldham, CEO of Captura, emphasized the advantages of this approach: “The ocean already acts as a massive carbon sink. By enhancing its natural processes, we can address emissions on a global scale.”

Captura’s upcoming plant in Hawaii will handle 10,000 tonnes of CO2 annually, a significant step up from their pilot plant in Los Angeles, which captures 100 tonnes each year.

Ebb Carbon: Enhancing Ocean Alkalinity

Ebb Carbon, based in South San Francisco, takes a slightly different approach by boosting ocean alkalinity to stabilize carbon as bicarbonates and carbonates.

This method not only captures CO2 but also mitigates ocean acidification caused by fossil fuel emissions.

Their pilot plant, located in Sequim, Washington, utilizes electrodialysis systems to treat seawater.

Matthew Eisaman, Ebb Carbon’s chief scientist, notes: “If deployed globally at industrial sites, our system could help draw down gigatonnes of CO2 each year.”

In 2025, the company plans to scale its operations with a larger facility, Project Macoma, capable of removing 500 tonnes of CO2 annually.

Equatic: A Hybrid Approach

Equatic, a spin-off from UCLA, combines direct air capture (DAC) with marine storage in a system that produces hydrogen as a valuable byproduct.

Their method involves electrolysis to separate seawater into its components, using the base stream to convert captured CO2 into stable forms such as bicarbonates and calcium carbonate.

Located in Los Angeles, Equatic’s pilot plant can remove 100 kilograms of CO2 per day.

Their commercial facility in Quebec, set to launch in 2025, will ramp up significantly, capturing over 300 tonnes of CO2 daily while producing 8,400 kilograms of hydrogen.

Thomas Traynor, head of engineering at Equatic, calls their approach “a holistic solution that addresses carbon removal and energy production.”

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Challenges on the Horizon

Despite their promise, marine carbon capture companies face substantial hurdles. One of the most pressing challenges is accurately measuring CO2 removal rates.

While physical measurements are logistically difficult, numerical modeling tools like the Regional Ocean Modeling System (ROMS) offer an alternative. However, reliance on models introduces uncertainty, which could impact the viability of selling carbon credits.

Environmental monitoring is another key concern. Ensuring these technologies do not harm marine ecosystems is critical to gaining public and regulatory acceptance.

“Regulators will have to watch this very carefully,” warned Andreas Oschlies, head of biogeochemical modeling at the Geomar Helmholtz Centre for Ocean Research.

Support From Big Players

Funding and recognition have flowed steadily toward these innovative startups. Programs like the U.S. Department of Energy’s $35 million Carbon Dioxide Removal Purchase Pilot Prize and the $100 million XPrize for Carbon Removal have spotlighted marine-based strategies as essential components of a diversified approach to tackling climate change.

Companies like Captura, Ebb Carbon, and Equatic have all been selected as finalists in these competitions, securing both financial support and industry credibility.

Additionally, collaborations with established organizations—such as Equatic’s partnership with Deep Sky for their Quebec plant—underscore the growing confidence in ocean-based solutions.

Scaling Up for Global Impact

The ultimate goal for these companies is to operate at a scale that can make a meaningful dent in global emissions.

Captura, for instance, envisions deploying its systems on decommissioned oil platforms, repurposing existing infrastructure to sequester captured CO2 beneath the seabed.

Ebb Carbon plans to colocate its technology with industrial desalination plants, leveraging existing water flows to minimize costs.

Equatic’s integrated approach offers a potential roadmap for scalability, combining carbon removal with hydrogen production to create dual revenue streams.

As the company prepares for its commercial launch in Quebec, its model illustrates how innovation and practicality can coexist.

Conclusion: A United Front Against Carbon Emissions

The efforts of Captura, Ebb Carbon, and Equatic highlight the immense potential of ocean-based carbon capture.

While technological, environmental, and economic challenges remain, these companies are charting a path toward a sustainable future.

As Steve Oldham aptly put it: “There’s enough carbon for everyone.”

With ongoing support from investors, governments, and international collaborations, these startups are poised to make waves—both in the oceans and in the fight against climate change.