The world’s largest carbon removal plant is here, and bigger ones are on the way

Mammoth, the largest industrial facility ever built to filter carbon dioxide from the air, has just opened in Hellisheiði, Iceland. It is run by Swiss climate technology company Climeworks, whose clients include JPMorgan Chase, Microsoft, Stripe and Shopify, among others.

Mammoth is the largest DAC plant in operation to date. But in the grand scheme of things, it’s relatively small compared to other projects in the works. Climeworks’ operations in Iceland aimed to show the world that this technology can work. Now, it will have to see if it can replicate that initial success in a growing market in the US.

Orca was the largest DAC plant in operation to date. Mammoth will be able to capture almost 10 times more CO2 than Orca when fully operational, around 36,000 tons of carbon dioxide per year. That’s still not a lot of carbon, considering Microsoft alone emitted close to 13 million metric tons of carbon dioxide in 2022.

But Climeworks and similar climate technology companies have much bigger ambitions in the US. The industry receives a lot of political support in the US, with the Biden administration channeling $3.5 billion in federal funds from the Bipartisan Infrastructure Act into the development of at least four CAD centers.

In Iceland, Climeworks DAC installations consist of modular “collection containers” with fans that draw in air. The air passes through a special filter that absorbs carbon dioxide. Once the filter is fully saturated, it will be heated to about 100 degrees Celsius (212 degrees Fahrenheit) to release the carbon dioxide. Climeworks partners with the company Carbfix to prevent captured CO2 from escaping back into the atmosphere by trapping it in Iceland’s basalt rock formations. They mix the CO2 with water and then pump this sludge underground, where it eventually turns into solid rock.

Climeworks benefits from abundant geothermal energy and natural underground storage sites in Hellisheiði. This allows it to run on renewable energy and avoid building a large network of gas pipelines to transport the captured CO2. This may not be the case for centers in the US, where any plans to build DAC plants already face concerns about high costs and polluting energy use. DAC companies will also likely face opposition to the construction of new gas pipelines from nearby residents.

Meanwhile, Mammoth is still a work in progress. To date, only 12 modular shipping containers have been installed at Mammoth, and Climeworks says it plans to install 60 more to complete construction this year.