Agence France-Presse

Operators say the Orca plant can suck 4,000 tonnes of CO2 out of the air every year and inject it deep into the ground to be mineralised

A worker on a CarbFix carbon injection well in Iceland in 2017. The company is involved in the new Orca plant designed to draw carbon dioxide out of the air and store it as rock. Photograph: Christian Science Monitor/Getty Images

The world’s largest plant designed to suck carbon dioxide out of the air and turn it into rock has started running, the companies behind the project said on Wednesday.

The plant, named Orca after the Icelandic word “orka” meaning “energy”, consists of four units, each made up of two metal boxes that look like shipping containers.

Constructed by Switzerland’s Climeworks and Iceland’s Carbfix, when operating at capacity the plant will draw 4,000 tonnes of carbon dioxide out of the air every year, according to the companies.

According to the US Environmental Protection Agency, that equates to the emissions from about 870 cars. The plant cost between US$10 and 15m to build, Bloomberg reported.

To collect the carbon dioxide, the plant uses fans to draw air into a collector, which has a filter material inside.

Once the filter material is filled with CO2, the collector is closed and the temperature is raised to release the CO2 from the material, after which the highly concentrated gas can be collected.

The CO2 is then mixed with the water before being injected at a depth of 1,000 metres into the nearby basalt rock where it is mineralised.

Proponents of so-called carbon capture and storage believe these technologies can become a major tool in the fight against climate change.

Critics however argue that the technology is still prohibitively expensive and might take decades to operate at scale.