New direct air capture plant poised for record removals

By Corbin Hiar | 05/07/2024 06:38 AM EDT

Climeworks’ Mammoth facility would multiply the industry’s ability to pull carbon out of the sky.

A Climeworks plant collects air near Reykjavik, Iceland, in 2021.

A Climeworks plant collects air near Reykjavik, Iceland, and releases it without carbon dioxide. Halldor Kolbeins/AFP via Getty Images

The world’s largest direct air capture plant is set to open in Iceland this week, a potentially significant development in the fledgling carbon dioxide removal industry’s quest to lower global temperatures.

Designed by the pioneering Swiss startup Climeworks, the so-called Mammoth plant would use fans, filters, piping and geothermal energy to permanently remove up to 36,000 metric tons of carbon dioxide from the atmosphere each year. That’s nine times the annual removal capacity of Orca, another Climeworks facility that is currently the world’s largest operating direct air capture plant.

Despite the technological achievement, Mammoth would only be able to remove less than 1 percent of the annual emissions of a typical coal-fired power plant, according to EPA data. But it is poised to be at least the second commercial facility that could pull tens of thousands of tons of carbon from the air annually, with much larger plants in development.


“It’s a signal of growth for the carbon removal ecosystem,” Ben Rubin, executive director of the Carbon Business Council, said of Mammoth’s planned debut Wednesday. The trade association represents more than 100 carbon management startups, but Climeworks, one of the industry’s most established players, is not a member of the council.

The new plant is opening as the planet continues to blow past heat records, with 10 consecutive months through March setting all-time highs. To avoid catastrophic temperature increases, scientists have determined that the world needs to both slash heat-trapping emissions while also massively scaling up deployments of carbon dioxide removal facilities.

Buyers from the private and public sectors have stepped in to create demand for such plants. Microsoft on Tuesday inked a record-setting 3.3-million-metric-ton agreement with Stockholm Exergi, a Swedish firm that would remove carbon by burning biomass for energy while capturing and storing the emissions. Last month, Denmark’s energy agency awarded contracts to three firms that have promised to collectively remove over 1.1 million metric tons of carbon from the air.

Meanwhile in the U.S., a biomass burial facility run by Graphyte — likely the world’s largest operating carbon removal plant — is on pace to scrub 15,000 metric tons of CO2 from the atmosphere in 2024. The company plans to increase the removal capacity of that Pine Bluff, Arkansas, plant next year to 50,000 metric tons.

Yet questions remain about the potential size of the market for carbon removal due to challenges associated with the cost or permanence of some removal methods.

The estimated price of removing a metric ton of CO2 ranges from $50 to $1,400, according to, an industry data clearinghouse. How long carbon stays out of the atmosphere when, for example, waste plant matter is converted into biochar is also a matter of dispute. By comparison, a metric ton of CO2 removed by a direct air capture facility costs around $730. One reason it’s so high is because operators say they can accurately measure the gas before locking it away forever in underground rock formations.

Climeworks broke ground on Mammoth in June 2022. By the end of last year, the facility was 90 percent complete, which the company described as a major logistical achievement.

“Having the core infrastructure in place and operational within just 18 months is a proof point of Climeworks’ ability to scale up quickly, with extremely fast development cycles, on its path to gigaton capacity by 2050,” Jan Wurzbacher, the company’s co-CEO, said at the time. A gigaton is 1 billion metric tons of carbon dioxide, equivalent to the annual CO2 emissions of about 257 coal plants.

Mammoth likely won’t be the largest direct air capture facility for long. In West Texas, Occidental Petroleum is constructing a DAC plant known as Stratos that is designed to remove up to 500,000 metric tons of CO2 annually. It’s scheduled to come online in mid-2025.

Occidental and a separate coalition that includes Climeworks have also been selected by the Department of Energy to develop two direct air capture hubs capable of eventually removing 1 million metric tons of carbon per year. Those projects are planned for southern Texas and southeastern Louisiana and backed by roughly $1 billion in federal grants.