Turning greenhouse gas into rock

A tech startup is tackling climate change by turning carbon dioxide into rocks – permanently storing the greenhouse gas deep underground


TWO WAYS TO EXTRACT CO2 

Carbon capture: Traps carbon dioxide (CO2) directly from smoke stacks at power stations
or factories and pipes it to injection site

Cost: $25 per tonne of CO2 

CO2

Carbon removal: Fans draw in air so CO2 can be collected by filters. When full, filters are heated to 100°C, releasing CO2 which is piped to injection site

Cost: $600 per tonne of CO2


Injection site: Gas is mixed with water and pumped 800-2,000m underground

Natural mineralisation: Carbonated water (acidic) reacts with basalt rock (porous and full of cavities). In under two years, elements such as magnesium, calcium and iron are released into water, combining with CO2 to form carbonate minerals that fill up rock cavities

Before
After

CO2 charged water
Water

Basaltic rock formation


Illustrations not to scale


Sources: Bloomberg, Carbfix, Climeworks 
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