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Graphic shows how carbon dioxide can be removed from the atmosphere and stored deep underground.


The tech startups turning carbon dioxide into stone

By Ninian Carter

September 9, 2021 - Two tech firms are tackling climate change by turning carbon dioxide into rocks – permanently storing the greenhouse gas deep underground.

Innovative tech firms in Iceland have turned on an experiment designed to see if they can capture carbon dioxide (CO₂) from the air and permanently store it deep underground in porous rocks, trapping the greenhouse gas forever, instead of allowing it to escape into the atmosphere and contribute to global warming.

Switzerland's Climeworks’ “Carbon Removal” method uses fans to draw air in so CO₂ can be collected by filters. When full, the filters are heated to 100°C, releasing the CO₂ which is then piped to an injection site.

The gas is then mixed with water and injected into basalt deep underground (a porous rock filled with cavities), where the carbonated water reacts with elements such as calcium, magnesium and iron to form carbonates that fill up the hollow pockets – providing a permanent and safe carbon sink in less than two years.

Another prototype design by Reykjavik-based Carbfix, is attempting to use “Carbon Capture” to trap gas directly from smoke stacks before sending the CO₂ to an injection site.

Carbfix says its carbon capture method is very cheap, working out at about $25 a tonne, which compares favourably with the current price of about $48 a tonne on the EU’s Emissions Trading System. Carbon removal, however, costs around $600 a tonne, making it prohibitively expensive at the moment.

In the last few years, capturing and storing CO₂ has become an area of immense interest for high-profile investors such as Microsoft founder Bill Gates, and Tesla and SpaceX CEO Elon Musk.

According to Carbfix, the global storage potential of using its technology is greater than the emissions from burning all fossil fuels on Earth.

The company is now working with global institutions to try and make its system applicable to types of rock other than just basalt, and aims to have one billion tonnes of permanently stored CO₂ by 2030.

PUBLISHED: 09/09/2021; STORY: Graphic News