Direct air capture costs: energy, materials and scale-up

Direct air capture cost depends on the equipment and energy needed to separate dilute atmospheric CO₂, maintain the capture material and deliver the CO₂ to durable storage. Capture cost, total removal cost and the price paid for a removal credit are different measures. The IEA's October 2025 estimate placed current direct air capture projects at USD 500–1,900 per tonne of CO₂. That dated range is a starting reference, not a current quotation or a guarantee that a particular design will reach a stated future target.

Why is there no single cost per tonne?

The IEA's October 2025 analysis attributes high direct air capture costs partly to atmospheric CO₂ concentrations of only about 420–430 parts per million. A plant must process large volumes of air for each tonne captured. Equipment configuration, local energy, climate, financing and proximity to storage then create further differences. The IEA's prospective cost reductions are conditional estimates, not demonstrated costs available to every purchaser.

Start by asking what the denominator measures. A cost per tonne entering a capture unit differs from a cost per tonne captured, transported, stored or verified as net removal. Check whether figures include construction, owner costs, financing, replacement material, storage monitoring and decommissioning. Record currency, price year, plant scale and whether the estimate concerns an early plant or a hypothetical mature industry. Without those boundaries, apparently similar numbers are not comparable.

Which energy requirements drive the cost?

The US Department of Energy's explanation distinguishes liquid-solvent and solid-sorbent approaches. The capture medium binds CO₂ and is regenerated so that concentrated CO₂ can be collected and the medium reused. Depending on the design, heat, vacuum and other process equipment contribute to regeneration. The useful question is the complete energy balance at the proposed site, rather than the lowest laboratory energy requirement for one isolated step.

Request separate electricity and heat requirements, with heat temperature and quality specified. Include air movement, regeneration, vacuum equipment, compression, cooling and other auxiliaries where applicable. Low-temperature heat is not automatically free: collecting it, bringing it to the plant and ensuring its availability may require capital and operating expenditure. Similarly, an attractive average electricity price does not establish that power is available whenever the process needs it.

Energy procurement affects both cost and the amount of net removal. NETL's solvent-system case study explicitly analyses how auxiliary loads, plant configuration and energy-related emissions affect the amount that must be captured to achieve a net-removal objective. Its results are modelled cases with stated assumptions. They should inform the questions asked of a project, rather than be transferred unchanged to a different technology or electricity system.

How do materials and utilisation affect operating cost?

Capture materials need to retain useful capacity and selectivity through repeated cycles. Ask for replacement frequency, the causes of degradation, material losses and the treatment or disposal route. A material that captures more CO₂ in a laboratory may still be expensive if manufacturing is difficult or replacement is frequent. Test performance in the intended air conditions, including the range of temperature and humidity, and identify which observations come from continuous operation.

Installed capacity is not annual delivered removal. Planned maintenance, commissioning, equipment outages and reduced performance all affect output. A cost model should show the route from nameplate capture to actual stored and verified tonnes. Fixed costs must then be allocated over that realistic output. If the model assumes high utilisation from the first operating month, ask how commissioning experience supports that assumption and how a delayed ramp-up changes financing needs.

Treat scale-up as a sequence of engineering questions. Larger contactors, repeated modules, faster manufacture and standardised installation can affect cost in different ways. A modular design may simplify replication while retaining site-specific power, storage and civil works. Require an explicit account of which costs fall with repetition, which depend on physical scale and which remain local. A learning curve is a scenario until operating and procurement evidence supports it.

What separates captured CO₂ from verified removal?

Captured CO₂ must be placed in a storage route that meets the relevant durability and accounting requirements before it can support a permanent-removal claim. Lifecycle emissions from equipment, energy, consumables and transport reduce net removal. Use a stated methodology and audit boundary. Utilisation in a product does not by itself establish permanent removal: the product's fate and the applicable accounting treatment determine the result.

Climeworks describes its monitoring, reporting and verification arrangements, including verification of capture and mineralisation activities before certification of removal batches. This is evidence about its reported process, not a universal verification rule for all suppliers. A buyer should identify the methodology, verifier, relevant reporting period and registry evidence attached to the removal actually contracted. A contract for future delivery is not a record that the tonnes already exist.

How can a simple calculation expose a misleading quotation?

Consider a hypothetical project with annual costs of USD 1 million and 2,000 tonnes of captured CO₂. Dividing gives USD 500 per captured tonne. If 200 tonnes of lifecycle emissions are deducted and all remaining captured CO₂ is durably stored, net removal is 1,800 tonnes and the cost becomes approximately USD 556 per net tonne. This illustration is arithmetic, not an estimate of any named project; further storage costs would increase the result if excluded from the original budget.

Repeat the calculation using lower output, higher energy prices and more frequent material replacement. Keep subsidies, tax treatment and financing assumptions visible rather than burying them in a single figure. The sale price can include margin, development risk and contractual protection, while a published engineering estimate may include none of these. A quoted credit price therefore cannot be used as a direct measure of the underlying capture plant's production cost.

Which evidence should determine the next commitment?

For a technology investor, the next evidence may be sustained operation at a representative scale and a reconciled material and energy balance. For a removal buyer, it may be a credible delivery schedule, a clear remedy for shortfall and verified accounting. For an industrial partner, it may be the availability of suitable energy and storage infrastructure. The Climeworks resource examines one supplier, while the readiness guide helps separate promising process research from the evidence needed for an operating commitment.