Direct air capture (DAC) plants are announced in tonnes of capacity per year. What a buyer receives is something else: credits that a registry issues after an audit, for the net CO2 removed in a period that has already ended. This piece puts the two side by side for the direct air capture projects we found in the registries CarbonMeld follows. Capacity figures come only from the operators’ own announcements and the project documents; credit figures come from the registry records as read on 8 November 2026.
The numbers, plant by plant
| Plant | Registry and methodology | Capacity announced | Production months with credits | Net credits issued | Credits vs capacity, same months |
|---|---|---|---|---|---|
| Orca, Iceland | Puro.earth, Geologically Stored Carbon | 4,000 t CO2 a year (Climeworks, September 2021) | 28 (Dec 2023 – Mar 2026) | 1,915 | 20.5% |
| Mammoth, Iceland | Puro.earth, Geologically Stored Carbon | up to 36,000 t CO2 a year, nameplate (Climeworks, May 2024) | 22 (Jun 2024 – Mar 2026) | 842 | 1.3% |
| Deep Sky Alpha, Canada | Isometric, Direct Air Capture protocol | estimated 450–600 t net in 2025 and 1,400–1,800 t in 2026 (project design document) | crediting period from 2 Aug 2025 | 3.02 | not computed |
| STRATOS, Texas | Verra, VM0049 | up to 500,000 t CO2 a year when fully operational (project description, April 2025) | none | 0 | not computed |
«Credits vs capacity» divides the net credits issued by the announced yearly capacity scaled to the same number of production months. Read these shares with the caveats set out below: Mammoth started operations with 12 of its 72 collector containers installed; credits are issued weeks to months after capture, so production after 31 March 2026 has no credits yet; and today’s net figures do not yet include most of the plants’ construction emissions, which are deducted in later years. For Mammoth, the project description filed on the registry gives two design figures: a nominal capacity of 36,000 tonnes of CO2 a year (page 2) and a carbon removal capacity of 33,000 tonnes a year (page 21); against 33,000 tonnes the share is 1.4%. Deep Sky Alpha’s figures are estimates in its own project design document (section A.9), not a plant capacity, so no share is computed. Deep Sky Alpha’s credits are the Isometric registry’s figure; CarbonMeld’s project page does not show Isometric issuances yet. STRATOS has no credits: on the Verra registry its registration is requested, and Verra’s public issuance report shows no issuance for it.
From captured CO2 to a credit
A credit is not a tonne of captured CO2. Under Puro.earth’s Geologically Stored Carbon methodology, the number of credits for a period is the gross CO2 stored minus the life cycle emissions of the whole supply chain, minus leakage and any release from storage (rule 4.3.1, equation 1, Edition 2024 version 5). Isometric’s Direct Air Capture protocol also credits the net amount: the CO2 stored, minus what would have been removed and stored without the project, minus the greenhouse gas emissions of the period (version 1.1, the version Deep Sky Alpha’s registry page names, section 7.4, equation 1).
The audit documents filed on the Puro registry show each step for Orca and Mammoth (registry pages: Orca, Mammoth; the document links below open CarbonMeld’s copies of the same files):
| Plant | Audited periods | Gross CO2 stored (audits) | Net CO2 eligible for credits | Net share | Gross CO2 stored per year vs capacity |
|---|---|---|---|---|---|
| Orca | Dec 2023 – Oct 2025 (7 audits) | 2,094.8 t | 1,624.2 t | 77.5% | about 1,093 t a year, 27% of 4,000 t |
| Mammoth | Jun 2024 – Oct 2025 (4 audits) | 879.6 t | 466.2 t | 53.0% | about 621 t a year, 1.7% of 36,000 t |
For example, the auditor’s statement for Mammoth’s first months (June to October 2024) lists 191.257 tonnes of CO2 stored, a reversal of 0.503 tonnes, 113.264 tonnes of project emissions and 77.49 tonnes eligible for credits (statement); the registry issued 77 credits for that period on 17 December 2024. The credits for the last period, November 2025 to March 2026, were issued on 31 July 2026; its audit documents are not yet in our copy of the registry files.
Construction emissions are deducted on a schedule, not all at once. The latest audit for Mammoth says the amortisation of its embodied emissions starts in 2029 (report, page 10). For Orca, 9.4% of these emissions were deducted between October 2023 and June 2024, and the rest is deducted from late 2026 to 2031 (report, page 9). The net figures above therefore deduct the plants’ operating emissions and, for Orca, the first 9.4% of its construction emissions; most of their construction emissions come later.
Why the gap is not the whole story
- Credits are issued after capture. At Puro, each of the issuances above came 47 to 122 days after the end of its production period. On 8 November 2026, the latest period with credits ends on 31 March 2026 for both Icelandic plants. Climeworks reports that Mammoth produced 675 tonnes of net carbon removal in the first six months of 2026, against 119 tonnes in the same period of 2025; credits for April to June 2026 are not on the registry yet.
- Plants ramp up. Mammoth started operations with 12 of its 72 collector containers installed, and Climeworks said the plant would be completed during 2024. Climeworks describes 36,000 tonnes as the nameplate capacity «once in full swing». Deep Sky Alpha tests several direct air capture technologies, and its design document says its yearly volumes may change as units are added, replaced or removed.
- A registry shows only its own credits. An operator may sell part of its output outside the registry, and those tonnes do not appear as issued credits. Credits issued are therefore not a measure of everything a plant captured.
What this comparison is not
This is not a CarbonMeld score, and it says nothing about the quality of the credits. It sets public figures from different sources side by side, with each source named. The score on a CarbonMeld project page is a separate thing: CarbonMeld’s own document-based assessment, informational and not investment advice, and not a rating given by the registry or the standard. STRATOS’s page shows registry data only: CarbonMeld has no analysis of that project yet.
Method
- Selection by methodology. We included projects registered under a methodology for capturing CO2 from the air with durable storage, where the project’s own documents describe direct air capture. We left out a Verra project named after direct air capture but registered under VM0043, a methodology for CO2 use in concrete production, with no credits issued (VCS-3823); an Isometric direct air capture project that the registry shows as cancelled (Project Juniper); and VM0049 projects that capture CO2 from other sources, such as Barnett Zero, which captures CO2 from natural gas processing (our article on its first credits). Puro.earth’s Geologically Stored Carbon methodology also covers other capture sources; Orca and Mammoth are the two direct air capture plants we found under it.
- Sources. Capacity: Climeworks’ announcements of Orca (8 September 2021) and Mammoth (8 May 2024), and the project documents linked above. Credits: the Puro registry, the Isometric registry and Verra’s public issuance report, read on 8 November 2026. Gross and net CO2: the auditors’ statements and reports filed on the Puro registry, linked from each project page.
- Dates. Registries change every day; every figure here is as read on 8 November 2026.
