What is seabed carbon capture? Sustainable manufacturing and soda water

What is seabed carbon capture? Sustainable manufacturing and soda water

Did you know we can now store carbon in the seabed and help reduce global warming?

In recent years scientists have been working on capturing carbon dioxide (CO2) produced by human activity and storing it in the seabed in the form of rock.

Facts about carbon capture on this page:

It’s well known that trees and vegetation extract carbon from our atmosphere and store it. However, this is not the only place carbon is stored on earth. Carbon is naturally stored in rock which occurs over millions of years as rock layers are formed from compressed carbon-containing soil.

Seabed carbon capture is the process of capturing carbon from the surface of the earth, for example, from power plant pollution. The carbon from this pollution is extracted and dissolved in water which produces carbonated soda water. The soda water is then injected into the seabed that contains the mineral basalt. The carbon dioxide in the soda water reacts with the minerals in the basalt to form new minerals, turning the basalt and carbon into rock. What an amazing discovery!

Not only is this an amazing piece of scientific research, but the time it takes for the soda water and basalt to turn into rock is only two years! 

This means that seabed carbon capture has the potential to rapidly reduce the carbon in our atmosphere and slow down global warming.

Who developed seabed carbon capture?

One of the organisations that have researched and developed seabed carbon capture is Carbfix.  

In 2007 four organisations created the Carbfix project, these were Reykjavík Energy, the University of Iceland, CNRS in Toulouse, and the Earth Institute at Columbia University USA. Numerous universities and research institutes have supported the project. The EU has provided funding via the Amphos 21, and Climeworks initiatives, and also via the University of Copenhagen.

Carbfix has worked with scientists to develop a commercially viable carbon capture process. The Carbfix solution is the result of collaboration between many academic institutes including ETH Zurich, the University of IcelandIceland GeoSurvey, the University of Geneva, the University of Lausanne, and the University College London (UCL). 

These collaborations resulted in the Carbfix project moving from an idea into a fully operational, cost-effective solution for capturing and storing CO2 in only seven years. The organisations involved are all part of the CO2SeaStone project.

What is the CO2SeaStone Project? 

The CO2SeaStone project is a partnership between ETH Zurich, UCL, and Carbfix and is the first-ever cycle of industrial carbon capture, transportation, and seabed storage. 

In summer 2022 the CO2SeaStone project began capturing and storing carbon. The initial phase of the project captured CO2 from an industrial wastewater treatment plant in Switzerland and then transported it overland to Rotterdam. The CO2 was then shipped to Reykjavík in Iceland and then transported overland to the storage site at the Reykjanes peninsula. Access to the carbon injection site was provided by geothermal specialist HS Veitur and by the Ministry of Environment and National Planning Agency of Iceland.

How do you store carbon in the seabed?

To be able to store huge volumes of carbon in natural rock you need an artificial process, like the CO2SeaStone project, that creates carbon-storing rock. Taking CO2 gas and converting it into rock.

The ability to convert CO2 into minerals has been known by scientists for some time. However, it is a recent discovery that basalt’s chemical composition and its high reactivity mean that it can be converted into minerals much faster than scientists expected.

The CarbFix collaboration has created this scaleable process for storing carbon in the seabed:

Diagram of the Carbix carbon storage solution - Industrial emission source (factory) - CO2 flows into an online injection well which is filled with Dissolved CO2 - H2O is released upwards through the ground - CO2 emissions also flow via pipes out to sea where it is dissolved in seawater and injected into the seabed via offshore injection rigs supplied by CO2 cargo transport ships


Step 1

The process starts by capturing carbon dioxide (CO2) from polluting industries like cement and chemical manufacturing, or commercial plants that convert waste to energy.

Step 2

The carbon dioxide is then transported overland as CO2 gas to a processing plant. 

Step 3

At the processing plant, the carbon dioxide is dissolved in water, turning it into carbonated water (soda water).

Step 4

CO2 tanks on a cargo ship

The soda water is transported to an ocean site which has a suitable mineral seabed such as basalt.

Step 5

The soda water is injected into the seabed where it reacts with minerals (such as basalt) in rock formations.

Step 6

Over time, approximately two years, the seabed minerals combine with the CO2 in the soda water. This forms carbonates that fill the empty spaces, or pores, in the rock.

The resulting underwater rock contains stable carbon that will remain in the seabed for thousands of years, permanently removing the carbon from the atmosphere.

Who was involved in seabed carbon capture research and development?

CarbFix developed the technology that provides this complete carbon capture and injection solution by collaborating with commercial, academic, and Government organisations. 

The scientific joint effort included:

These organisations have created an amazing carbon storing technology that only needs three things to work: the right type of seabed rocks e.g. basalt, water, and a source of carbon dioxide.

Basalts or other reactive rock formations + CO2 dissolved in water = Solid carbonates 

A positive feature of this process is that basalt is one of the most common minerals on earth making the process possible around the globe.

Also, the project scientists have discovered that the mineralisation process converts 95% of the injected CO2 in less than two years. Amazing!


Go deeper

Here are the details. You can learn more about the CarbFix technology from the resources below.

Project CO2SeaStone. CarbFix. 2022. https://www.carbfix.com/co2-seastone

Mineralization potential of water-dissolved CO2 and H2S injected into basalts as function of temperature: Freshwater versus Seawater. 2021.

Chiara Marieni, Martin Voigt, Deirdre E. Clark, Sigurður R. Gíslason, Eric H. Oelkers

  • Géosciences Environnement Toulouse (GET), France
  • Institute of Earth Sciences, University of Iceland, Iceland
  • Iceland GeoSurvey (ÍSOR), Iceland


An experimental study of basalt–seawater–CO2 interaction at 130 °C. 2021. Voigt, M., Marieni, C., Baldermann, A., Galeczka, I.M., Wolff-Boenisch, D., Oelkers, E.H., Gislason, S.R.

  • Institute of Earth Sciences, University of Iceland, Sturlugötu 7, Reykjavík, 102, Iceland
  • Géosciences Environnement Toulouse (GET) – CNRS, 14 Avenue Édouard Belin, Toulouse, 31400, France
  • Institute of Applied Geosciences & NAWI Graz Geocenter, Graz University of Technology, Rechbauerstr. 12, Graz, 8010, Austria


Carbfix Scientific Papers. 2022. https://www.carbfix.com/scientific-papers

CarbFix How It Works. 2022. https://www.carbfix.com/how-it-works

Carbfix Tests Using Seawater to Mineralize CO2. Carbon Capture Magazine. 2022 https://carboncapturemagazine.com/articles/319/carbfix-tests-using-seawater-to-mineralize-co2

ETH Zurich is a public research university in the city of Zürich, Switzerland. Founded by the Swiss Federal Government in 1854 with the stated mission to educate engineers and scientists, the school focuses primarily on science, technology, engineering, and mathematics.

University of Iceland The University of Iceland is a public research university in Reykjavík, Iceland and the country’s oldest and largest institution of higher education.

Iceland GeoSurvey is a consulting and research institute providing specialist services to the Icelandic power industry, the Icelandic government and foreign companies, in particular in the field of geothermal sciences and utilisation.

University of Geneva is a public research university located in Geneva, Switzerland. It was founded in 1559 by John Calvin as a theological seminary. It remained focused on theology until the 17th century when it became a centre for enlightenment scholarship.

University of Lausanne, Switzerland was founded in 1537 as a school of Protestant theology, before being made a university in 1890. The university is the second oldest in Switzerland, and one of the oldest universities in the world to be in continuous operation.

University College London, which operates as UCL, is a public research university in London, United Kingdom. It is a member institution of the federal University of London and is the second-largest university in the United Kingdom by total enrolment and the largest by postgraduate enrolment.

If you see anything in this article that’s incorrect or you want to add to it please get in touch, we’ll be happy to update it.

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