SVERY AFTER At 6 p.m. on September 9, the Orca carbon capture plant, just outside Reykjavik in Iceland, turned on its fans and began to suck carbon dioxide out of the air. The sound was subtle, much like a gurgling stream. But the creators of the plant hope it will mark a big change in humanity’s interaction with the climate.
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Orca is, so far, the largest facility in the nascent “direct air capture” industry, which aims to remove CO2 of the atmosphere. When sealed underground, such a CO2 counts as ânegative emissionsâ, an essential but underdeveloped method of combating global warming. To prevent temperatures from rising 1.5 Â° C or even 2 Â° C above pre-industrial averages, according to the Paris climate agreement, hundreds or trillions of tons of CO2 will have to be removed from the atmosphere in the second half of the century.
Currently, the only way to do this is to plant trees, an option that is not entirely without its drawbacks. Trees burn in forest fires and can be felled. When this happens, much of the carbon they store escapes. The Orca plant shows another way. Climeworks, the company that owns it, has developed chemical filters that capture CO2 when air passes through them. When heated, they release CO2again, generating a flow of gas which is turned over to another company called Carbfix.
Carbfix routes the gas to nearby wells, mixes it with water, and pumps the resulting carbonated water into bedrock. In Iceland, this consists almost entirely of volcanic basalts, which contain minerals that react with carbon dioxide to form calcium carbonate, a white crystal which is the main ingredient in limestone. Thus, the complete operation extracts CO2 of air and turns it into rock. Tests have shown that Icelandic basalts can sequester CO2 in solid rock within two years. Electricity comes from a geothermal power station located nearby.
A catch is the volume. Orca will capture 4,000 tonnes of carbon dioxide per year, out of around 35 billion tonnes produced by burning fossil fuels. Climeworks is “confident” that it will be able to reach millions of tonnes before the end of the decade. (A mind-boggling old ambition of reaching 1% of emissions by 2025 is no longer on the agenda.)
Another is the cost. It costs Orca between $ 600 and $ 800 to sequester a tonne of carbon dioxide, and the company sells offset packages online for around $ 1,200 a tonne. The company believes it can increase its costs tenfold thanks to economies of scale. But there does not appear to be a shortage of customers willing to pay the current high price. Even as Orca fans ramped up, around two-thirds of its lifetime carbon removal offering had already been sold. Customers include companies looking to offset part of their emissions, such as Microsoft, Swiss Re (and The Economist), as well as more than 8,000 individuals.
Climeworks is not the only one to have spotted the opportunity. Using a different chemistry, Carbon Engineering, a Canadian company, is preparing to commission its own carbon cleaning facilities. It will take more than these pioneering engineers and financiers to build an industry the size of a gigaton. But the fans turn around. â
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This article appeared in the Science and Technology section of the print edition under the title “Sucking money from thin air”