In September, Climeworks flipped the switch on Orca, the largest plant to date that is designed to remove carbon dioxide from the air.
The facility, outside Reykjavik, Iceland, can capture 4,000 metric tons of carbon dioxide every year. Large fans suck air through a filter, where materials bind with CO2 molecules. The company’s partner, Carbfix, then mixes the carbon dioxide with water and pumps it underground, where it reacts with basalt rock and eventually turns into stone. The facility runs entirely on carbon-free electricity, mainly from a nearby geothermal power plant.
Each module at Orca is made up of a dozen carbon removal units. Air passes through grates and over a filter that traps carbon dioxide with adsorbent chemicals. When the filters are full, grates close across the front of the unit and pipes pump heat into the enclosed space, releasing CO2 from the filters.The carbon dioxide is then pumped to an area where it's prepared for storage before the gates open again to restart the process.
To be sure, 4,000 tons isn’t that much. It’s less than the annual emissions of 900 cars. And it’s a tiny fraction of the billions of tons of carbon dioxide the world will likely need to pull out of the atmosphere to prevent global warming from soaring past 2 °C over preindustrial levels, according to a variety of studies.
Orca is made of modules that can be combined in different ways, making the plant easier to replicate around the world. Climeworks put its first plant in Iceland in part to take advantage of the country’s abundant geothermal power, so the facility can minimize the emissions it generates in the process of capturing carbon dioxide.
On the back of each module, fans blow filtered air back into the atmosphere. Flexible covers on the fans ensure that loose bits from the filters aren’t blown away by the strong Icelandic winds. These covers will likely be needed just for the first year, while the units are tested.
After being captured, carbon dioxide is transformed into solid carbonate minerals, seen here as light spots in a matrix of dark basalt rock.
Carbon dioxide is pressurized and mixed with water before being transferred through massive pipes to Carbfix, the company that pumps it underground to be stored.
Injection wells operated by Carbfix pump carbon dioxide 1,000 meters underground, where it reacts with basalt rock and is locked into mineral form within two years.
The hope is that building more and larger plants to capture carbon from the air will help companies figure out how to optimize operations, drive down the costs, and realize economies of scale. Climeworks estimates it will reduce costs between $600 and $800 per ton of carbon, to around $100 to $150, by the late 2030s.
A growing number of individuals and companies, including Microsoft, Stripe, and Square, are already paying today’s high costs to suck carbon out of the air as they strive to cancel out their emissions. That’s providing crucial early revenue.