Climeworks switches on Mammoth, world's largest direct air capture plant

Direct air capture and storage (DAC+S): fan-driven collector containers filter CO2 from ambient air, partner Carbfix mineralizes it in Iceland's basalt, and Climeworks sells the verified removal credits to corporations.

That direct air capture can scale from a 4,000-tonne proof plant to megaton hubs — and that corporates will prepay for verified permanent removal before costs fall.

$650M Series E in April 2022 (CHF 600M), the largest round ever for a carbon-removal startup, co-led by Partners Group and GIC with Baillie Gifford, John Doerr, M&G and Swiss Re.

Founded in 2009 by ETH Zurich mechanical-engineering graduates Christoph Gebald and Jan Wurzbacher, who wanted to engineer a fix for the melting glaciers they climbed. In 2017 Climeworks became the first company to sell CO2 captured from ambient air, and in September 2021 it opened Orca in Iceland, the world's first commercial DAC+storage plant.

Climeworks broke ground on Mammoth in June 2022 and closed its $650M Series E the same spring. On 8 May 2024 Mammoth captured its first CO2 with 12 of 72 collector containers installed; its 36,000-tonne-per-year nameplate is about ten times Orca's. Three US megaton-hub proposals won DOE selection with over $600M in federal funding, and Project Cypress in Louisiana received an initial $50M in March 2024.

Still running and expanding: Mammoth ramped through 2024, and Climeworks — which calls itself the most-deployed DAC company — is developing US megaton hubs plus projects in Norway, Kenya and Canada.

Iceland gave Climeworks cheap geothermal heat and basalt storage, letting it prove permanent removal end-to-end instead of selling paper offsets.

Pre-selling credits to Microsoft, JPMorgan, Stripe and Shopify funded plant two while plant one was still running.

A modular collector-container design lets Climeworks copy-paste capacity instead of custom-engineering each site.

DOE hub funding de-risked the leap from 36,000 tonnes to megatons with over $600M of public support.

Orca proved the chemistry, won prepaying customers and policy backing, then justified a record round for a 10x plant. Capital-intensive climate tech de-risks by shipping the first unit.

As of May 2024 Mammoth was ramping: 12 of 72 collectors installed, the rest scheduled through 2024, with the first CO2 already sent to Carbfix for mineralization. Climeworks was simultaneously pursuing three US megaton hubs selected by the DOE — Project Cypress in Louisiana leading with an initial $50M and Microsoft as a customer — plus development in Norway, Kenya and Canada. The company says it processes close to 200 million data points daily across its two commercial plants and remains the most-deployed DAC operator; its roadmap is megaton-scale hubs by 2030 and gigaton capacity by 2050.