As much as 71 per cent of the planet is made up of water, which accounts for 33 per cent of all CO2 emissions. Moreover, 1 litre of water contains 150 times more CO2 than 1 litre of air. Therefore, Dutch startup SeaO₂ has developed an innovative way to extract carbon dioxide (CO2) from seawater, which in turn helps to remove CO2 from the atmosphere.

The technology was developed at TU Delft and at the Wetsus laboratories in Leeuwarden. An electrochemical process strips CO2 from the water and leads the carbon-free water back to the sea where it will again absorb CO2 from the air. SeaO2 aims to remove a gigatonne of CO2 from the oceans by 2050 to protect the earth from further warming.

Natural balance

SeaO2’s mission is to protect the earth from further warming by reducing the concentration of CO2 in the sea and – as a result – in the air. In this way, it also counteracts ocean acidification, contributing to the ocean ecosystem.

The Direct Ocean Capture (DOC) technology developed by the company uses only seawater and green electricity – and thus no chemicals or heat – to split seawater into an acidic and an alkaline stream. With the acid created and the help of a vacuum technique, 99 per cent of the carbon dioxide is then removed from the larger water stream.

What remains is CO2-free seawater that, once back in the ocean, regains its natural balance by absorbing CO2 from the air. 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 in a variety of locations. It can be switched on and off within seconds and is therefore also perfectly 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 summer 2024. SeaO2’s first round of funding is planned in the coming months. Also next year, with an investment of EUR 5-10 million, they aim to further scale up to capturing 2.5 kilotonnes of CO2 by 2025 and 1 megatonne by 2030.

‘Solution to the climate problem lies in the sea’

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

‘The ocean is a giant sponge for carbon dioxide, a third of all carbon dioxide emissions end up in the sea,’ adds Ruben Brands, co-founder and CEO of the company. ‘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.’

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