Climeworks' Mammoth captured six times more CO₂ — 675 tonnes of a 36,000-tonne design

Climeworks reported on 10 September 2026 that Mammoth, its direct-air-capture plant at Hellisheiði in Iceland, removed 675 tonnes of CO₂ in the first half of 2026 — close to six times the same period a year earlier — while the plant's operating cost fell by more than half. The company attributes the gain to upgraded sorbent and collector-container design, which it says more than doubled capture performance per container under real operating conditions, with the first upgraded containers now reaching their design figures. Climeworks did not disclose a cost per tonne. Mammoth was announced with a nameplate capacity of 36,000 tonnes a year. The tracker records the improvement.

Why it matters

Two numbers, and both belong in the same sentence. Six times more captured and half the running cost is a real engineering result, achieved on operating hardware rather than in a model, and it addresses the specific failure that has dogged direct air capture: plants that run far below the figure they were announced at. Climeworks saying its upgraded containers now hit their design performance is the first half of that problem being solved.

The second half is the gap that remains. 675 tonnes over six months annualises to roughly 4% of Mammoth's 36,000-tonne nameplate. Against the offtake contracts the sector has sold — Microsoft alone has purchased millions of tonnes of removal — the delivered tonnage from the world's largest DAC plant is a rounding error, and that mismatch, not the technology, is what makes the industry's credibility fragile. A sixfold improvement on a small number is still a small number, and Climeworks has been more willing than most to publish it.

Withholding the cost per tonne is the notable omission. "Down more than half" is meaningful only against a starting figure that has been estimated publicly at several hundred to over a thousand dollars a tonne, versus the roughly $100 the sector treats as the threshold for scale. Halving from an undisclosed base does not tell you which side of that line the plant is on.

What to watch

Whether Mammoth's full-year 2026 tonnage keeps the trajectory, whether Climeworks publishes a cost per tonne, and whether the upgraded collector design is retrofitted across the whole plant or only the containers reported here.