US startup’s new system to capture 4,000 tons of CO2, produce 100 tons of hydrogen

As the climate crisis accelerates, scientists are increasingly looking to carbon removal technologies to curb the dangerous temperature rise.

A promising innovation comes from Los Angeles-based startup Equatic, which claims its ocean-based carbon removal system not only captures carbon but also produces green hydrogen—a dual-purpose approach attracting significant attention.

“We take CO2 out of the atmosphere and we store that permanently. The second thing we do is produce green hydrogen,” Edward Sanders, Equatic’s CEO, told BBC in an interview.

How it works

Equatic’s process begins with pumping seawater into an electrolyzer powered by renewable energy sources like wind or solar. The electrolyzer separates the water into hydrogen, oxygen, acid, and an alkaline slurry.

The alkaline slurry captures atmospheric CO2, transforming it into stable bicarbonates and carbonates, which are released back into the ocean. The acid waste stream is neutralized with rocks before discharge, ensuring minimal environmental impact.

Notably, the technology employs an oxygen-selective anode that eliminates the need for seawater desalination—often required in similar processes to avoid producing harmful chlorine gas.

This breakthrough allows direct electrolysis of raw seawater, a “holy grail” for electrochemists, according to Equatic’s senior scientist and co-founder, Xin Chen.

Equatic is scaling its technology through pilot plants in Los Angeles and Singapore, each removing 30-40 tonnes of CO2 annually. The company is constructing a larger plant in Singapore capable of capturing 4,000 tonnes of CO2 and producing 100 tonnes of hydrogen annually. A commercial-scale plant in Quebec, planned for 2026, aims to remove over 100,000 tonnes of CO2 per year.

The company faces scrutiny over its energy use and environmental impact. Processing seawater at scale—350 tonnes for each tonne of CO2 removed—raises concerns about disrupting marine ecosystems. Critics warn of potential “dead water” zones and argue that large-scale marine CO2 removal could jeopardize food security and biodiversity.

The debate over ocean carbon removal

Equatic’s supporters point to the vast storage potential of oceans, which naturally absorb 25% of global CO2 emissions. Marine carbon removal, they argue, could complement land-based methods while requiring less infrastructure.

However, skeptics remain unconvinced. Environmental groups like the Center for International Environmental Law warn of risks to ocean chemistry and ecosystems. Marine scientist James Kerry argues that even advanced ocean technologies may play only a marginal role in reducing global emissions.

Equatic maintains that its process is environmentally sound, adhering to global standards and conducting ongoing monitoring. The company also plans marine ecosystem studies for future projects.

Equatic aims to monetize its efforts through carbon credits, which allow companies to offset emissions by purchasing verified CO2 removal. The company has pre-purchase agreements with Boeing and is in talks to sell credits to the U.S. government at $460 per tonne. By also producing hydrogen, Equatic diversifies its revenue streams, adding value to its technology.

Critics of carbon credits argue that they often overpromise and underdeliver. In response, Equatic has shifted to a closed-loop system, enabling precise measurement of CO2 captured—essential for verifying credits’ effectiveness.

The ocean’s role in combating climate change is increasingly recognized, but experts stress the need for rigorous governance and monitoring. Marine carbon removal remains in its infancy, with significant gaps in knowledge and uncertain impacts.

Despite the hurdles, Equatic envisions a future where its plants can remove millions of tonnes of CO2 annually. While ambitious, Sanders believes the technology is vital for addressing “legacy CO2” in the atmosphere. As Chen notes, “No removal solution later is as good as mitigation now”