A giant carbon-capturing machine has been turned on in Iceland.

The operators of a new plant called ‘Orca’ say it can suck 4,000 tonnes of CO₂ out of the air a year and inject it deep into the ground.

It is the world’s largest carbon-capture-from-air device. 

The machine consists of four units, each made of two metal boxes about the size of shipping containers.

The project by Switzerland’s Climeworks and Iceland’s Carbfix cost around $15 million to build and can make up for the annual emissions of about 250 US residents.

Climeworks says it is targeting 500,000 tonnes of CO₂sequestration by the end of the decade.

Of 16 installations Climeworks has built in Europe, Orca is the first to permanently dispose of the CO₂ rather than recycling it.

The plant draws in air with huge fans, bringing it into contact with chemicals that selectively remove CO₂ while releasing nitrogen, oxygen and other gases back into the atmosphere. It then heats the carbon-rich chemicals to about 100°C to release CO₂ as a pure gas.

The gas is mixed with water and injected deep into basaltic rock. It takes about two years underground for the dissolved CO₂ to crystallise into a mineral.

It is one of the few genuinely effective carbon capture and storage technologies in operation today, although it is expensive. 

Individuals can purchase carbon offsets for up to $1,200 per tonne of CO₂, but Climeworks aims to have that cost around $200 by 2035, when its operations are at full scale.