Getty ImagesIt could be a scene from a science fiction novel. Amid the dark, mossy lava fields stand a cacophony of noisy machines the size of shipping containers, domes and twisting silver pipes.
Located 30 km (19 mi) southwest of Iceland’s capital, Reykjavik, the facility is the world’s largest direct air capture (DAC) facility.
The product, called Mammoth, was developed by Swiss company Climeworks.
It has been operating for two months, sucking global warming carbon dioxide (CO2) from the air and storing it deep underground, where it turns to stone.
Currently 12 collection containers have been installed, but in the coming months 72 collection containers will surround the large processing hall.
“This will allow us to capture 36,000 tonnes of carbon dioxide per year,” Climeworks chief commercial officer Douglas Chan told the BBC.
The aim is to reverse emissions that are already being released into the atmosphere.
Each collector unit has a dozen powerful fans that can draw in enough air to fill an Olympic swimming pool every 40 seconds.
“The technology relies on taking in a lot of air, then slowing it down so a filter can capture it, and then expelling the air out the end,” Mr Chen said.
Carbon dioxide makes up only a tiny fraction of the atmosphere (0.04%), so capturing it requires a lot of electricity.
For Mammoth, electricity comes from a nearby geothermal power plant, so the plant produces no emissions when it operates.
Once full, the collection chamber is flushed with hot steam and piped to the processing hall.
In the hall, Mr. Chen pointed to two huge balloons overhead, which together held a tonne of carbon dioxide.
The captured CO2 is then mixed with fresh water in an adjacent tower.
“It’s almost like a shower,” explains Dr Martin Vogt of Iceland’s Carbfix, which has developed a process to turn CO2 into stone.
“Water drips down from the top. The CO2 goes up, and then we dissolve the CO2.”
Two nearby white dome-shaped roofs conceal injection wells, where water containing carbon dioxide is pumped more than 700 meters underground.
“This is fresh basalt,” Dr. Voigt said, showing me a piece of black rock from a recent eruption that was riddled with tiny holes. “You can see there’s a lot of porosity.”
Iceland has an abundance of volcanic basalt, and this bedrock acts like a reservoir: When carbon encounters other elements in the basalt, it reacts and solidifies, locking it into carbonate minerals.
“Here you can see a lot of the pores are now filled with white specks,” Dr. Watt said as he processed a sample of the drilled rock.
“Some of these are carbonate minerals. They contain mineralized carbon dioxide.”
Dr. Voigt excitedly said that this process is very fast. “We are not talking about millions of years.”
“In the pilot project, about 95% of the CO2 was mineralized within two years. That’s incredibly fast. At least on a geological time scale.”
Mammoth can remove 36,000 tonnes of carbon dioxide per year, equivalent to removing 8,000 gasoline cars from the road, and is nearly 10 times the size of Climeworks’ first commercial plant, Orca.
It costs Climeworks nearly $1,000 (£774) to capture and store one tonne of carbon dioxide. To make money, it sells carbon offsets to clients.
“Mammoth has sold nearly a third of its lifetime capacity,” said Mr Chen, who believes technological improvements and increased scale will reduce costs in the future.
“By the end of the century, we hope to have capture costs between $300 and $400.”
Its clients include Microsoft, H&M, JPMorgan Chase, Shopify and Lego; as well as more than 20,000 individuals who subscribe on the Climeworks website.
Brian Marrs, senior director of energy and carbon removal at Microsoft, previously told the BBC: “We follow the science.”
“Carbon removal has to be part of the equation. You can’t reduce emissions that are already in the atmosphere, you have to remove them.”
Ultimately, the Mammoth project will pale in comparison to the U.S. Cypress project, which is set to break ground in 2026. Climeworks hopes the project will be able to remove up to a million tonnes of carbon dioxide per year and use new technology that it says will be cheaper and more energy efficient.
However, critics believe that DAC technology is overhyped, pointing out its high cost, high energy consumption and limited scalability.
Those critics argue that it is far more efficient to capture CO2 where it is emitted.
“It’s much easier to remove CO2 straight from the chimney,” said Dr. Eduard Julius Solness, a professor at the University of Iceland and a former Icelandic environment minister.
Despite repeated calls to cut emissions, the amount of planet-warming carbon dioxide emitted last year hit a record high.
The United Nations Intergovernmental Panel on Climate Change has warned that emissions must be cut urgently, but that this will still not be enough to prevent harmful global warming.
Many climate scientists agree that carbon removal is also necessary, but opinion is divided. A variety of approaches have been proposed, with some warning against reliance on so-called technological fixes that could prevent polluters from changing their ways.
Currently, carbon removal is not happening at the scale required.
“We emit about 40 billion tonnes of carbon dioxide into the atmosphere every year, so this [DAC] It won’t have any impact on the big issues,” Dr. Sólnes said.
“We need to move away from fossil fuels and look for other energy sources,” he asserted. “But I think we should use every avenue available to us to solve this problem.”
More DAC projects are being launched. According to the International Energy Agency, there are 27 plants in operation worldwide, but only four of them capture more than 1,000 tons of carbon dioxide per year.
Plans for another 130 facilities are also in the works, and the U.S. government has allocated about $3.5 billion to start three large hubs with the goal of eventually reducing one million tons of carbon dioxide per year.
However, Doug Chan is convinced that DAC can help combat global warming. “I firmly believe that direct air capture and other engineering solutions will help us combat climate change.”
