CO2 removal inspired by seashells

The ocean could hold the key to dual-purpose carbon capture and hydrogen fuel production

Spotted: Researchers recently found that we will need to remove around eight billion tonnes of CO2 from the atmosphere every year by mid-century – around four times our current rate of removal – to meet 1.5 degrees Celsius Paris Agreement targets. Oceans are our planet’s largest natural carbon sink, but without help, they cannot keep up with our rate of emissions production.

Capturing carbon directly from the air is one way we can help, but traditional approaches face limitations: scaling challenges, high costs, and environmental risks. Now, a novel solution leverages ocean electrolysis to tackle these challenges, offering a scalable, cost-effective, and low-energy pathway. What’s more, it also produces clean hydrogen as a byproduct. 

The dual-purpose technology, created by Equatic, applies electrolysis to seawater to convert CO2 into a stable, solid carbonate form, mimicking natural processes like seashell formation at an accelerated rate. Equatic’s approach returns clean water to the ocean, serving to also accelerate natural carbon capture rates, and produces hydrogen – a green fuel that could help to power hard-to-decarbonise sectors and is used to fuel Equatic’s operations in a self-sustaining energy loop. “Our commercial plant takes just five minutes to remove one tonne of carbon (…) An equivalent area of open ocean takes 12 months,” Edward Sanders, COO at Equatic, explained to Springwise. 

Equatic’s offering is unique in that it integrates both direct air capture (DAC) and seawater electrolysis – a combination that enables both future and legacy carbon removal. According to Sanders, recently, “one of its co-founders, Dr Xin Chen, invented a method to manufacture oxygen-selective anodes, enabling scalable and cost-effective hydrogen production using seawater.” This offers an answer to previous attempts to create hydrogen using seawater electrolysis, which have failed to scale effectively because they produce chlorine gas as a byproduct, which is both toxic and corrosive. 

The technology is already in action. Equatic has pilot plants in Los Angeles and Singapore that together have removed over 75,000 tonnes of CO2 and generated 2,000 tonnes of clean hydrogen. Plans are underway for commercial-scale installations, with a major plant in Quebec aiming to capture 109,500 tonnes of CO2 annually and generate 3,600 tonnes of green hydrogen by 2026.

Equatic expects its carbon capture costs to drop as low as $30 per tonne (current prices are around the $600 to $700 mark). If realised, this makes the company’s ambitious goal of removing five million tonnes of CO2 by 2030 increasingly within reach. In recognition of Equatic’s work, the company was named a finalist in this year’s Earthshot Prize.

Written By: Oscar Williams