As much as 71% of the planet is made up of water, which accounts for 33% of all CO2 emissions. Moreover, 1 liter of water contains 150 times more CO2 than 1 liter of air. 

Dutch start-up SeaO2 has developed an innovative way to extract carbon dioxide (CO2) from seawater, which in turn helps remove CO2 from the atmosphere.

Start-up SeaO2 extracts carbon dioxide (CO2) from seawater. The technology was developed at TU Delft and the Wetsus laboratories in Leeuwarden. An electrochemical process strips CO2 from the water and leads the carbon-free water to the sea where it will again absorb CO2 from the air. SeaO2 has set a target of removing one gigatonne of CO2 from the oceans by 2050 to protect the earth from further warming.

Visual of SeaO2's Direct Ocean Capture process. Photo: SeaO2

Natural balance

SeaO₂'s mission is to protect the earth from further warming by reducing the concentration of CO2 in the ocean and thus, in the air. The technology also helps prevent ocean acidification which promotes the ocean ecosystem.

The Direct Ocean Capture (DOC) technology developed by the company uses only seawater and green electricity (free of chemicals and heat) to split seawater into acidic and alkaline streams. Using the acid collected and a vacuum technique, 99% of the carbon dioxide is then removed from the larger water stream. What remains is CO2-free seawater that regains its natural balance by absorbing CO2 from the air once back in the ocean.

The extracted CO2 can be stored or used in various applications, such as the production of green methanol, sustainable aviation fuels and plastics.

From prototype to scale-up

SeaO2's DOC technology is energy efficient and can be applied at different locations. It can be switched on and off within seconds and is suited for grid balancing.

The SeaO2 prototype already removed the first CO2 from the water at the Afsluitdijk last year. The launch of the pilot plant, with an annual capacity of 250 tonnes, is scheduled for this summer.

SeaO2's first round of funding is planned in the coming months. Next year, with an investment of 5 to 10 million euros, they aim to further scale up to capture 2.5 kilotonnes of CO2 by 2025 and 1 megatonne by 2030. This is good news for our oceans, which are threatened by increasing acidification.

With the help of the sea

Rose Sharifian, co-founder and CTO of SeaO2, received her PhD on carbon absorption from the ocean from TU Delft in 2020. “The technology that I developed under the guidance of Professor David Vermaas, our third founder, is extremely sustainable and completely free of chemicals. On the one hand, seawater and green energy go in, and on the other hand, CO2 and more alkaline water come out. In this way we can eventually help solve the climate problem using the sea.”

Ruben Brands, co-founder and CEO of the company, adds, “The ocean is a giant sponge for carbon dioxide, with a third of all carbon dioxide emissions ending up in the sea. The concentration of carbon dioxide in the ocean is 150 times higher than that in the air, making it a very good source for capturing CO2. In short: the solution to the climate problem lies in the sea.”