The archive · Climate & Energy · Strategic decision · 2009–2024
Climeworks switches on Mammoth, world's largest direct air capture plant
Swiss DAC pioneer opens its second Iceland plant — 10x Orca at 36,000 tCO2/yr — betting modular carbon removal scales to megatons.
Climeworks
What the business is
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.
Starting capital：$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.
How it started
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.
What happened
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.
How it ended up
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.
Background
Climeworks is a Swiss direct air capture company that builds machines to pull CO2 out of ambient air and store it permanently underground. Its Mammoth plant in Hellisheiði, Iceland — switched on 8 May 2024 — is the largest DAC facility in operation, designed for up to 36,000 tonnes of CO2 per year, roughly ten times the output of its predecessor Orca.
The company started in 2009 as an ETH Zurich spin-off and in 2017 became the first to sell captured airborne CO2 commercially. Orca (2021) proved the full loop: renewable heat from Iceland's geothermal fields plus Carbfix's basalt mineralization turned captured carbon into stone, and Microsoft, JPMorgan, Stripe and Shopify became credit buyers.
Mammoth is the bet in concrete form: Climeworks raised a $650M Series E in April 2022 — the largest round ever for a carbon-removal startup — and started building the 36,000-tonne plant the same year. Twelve of 72 modular collectors were installed at launch, with the rest scheduled through 2024. The plan is not to stop at plants but to replicate Mammoth as megaton hubs, including three US proposals selected by the DOE for over $600M in federal funding.
The open question is economics: DAC still costs far more than most emitters will pay, and Mammoth removes less in a year than Microsoft alone emits in a month. Climeworks' answer is scale and field experience — close to 200 million data points a day from two operating plants — while it signs multi-year offtakes to fund the next generation.
What has to be true
- 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.
What can be applied
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.
Aftermath
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.
Sources
- Climeworks switches on world's largest DAC plant
- The world's largest carbon removal plant is here, and bigger ones are on the way
- Climeworks Announces The Largest Carbon Removal Deal Ever
- From melting ice to carbon removal: how glaciers inspired Climeworks
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