Direct Air Capture: the technology that sucks CO₂ out of the air. But does it actually work?

Of all the technologies designed to remove carbon from the atmosphere, Direct Air Capture with Carbon Storage – or DACCS – comes closest to the idea of a giant CO₂ vacuum cleaner: industrial systems that pull air in, strip out the carbon dioxide, and lock it away in deep geological formations for thousands of years.

This isn’t science fiction. Pilot plants and early commercial facilities are already up and running in Iceland, the United States, and Canada. That said, DACCS remains an expensive, energy-hungry technology that’s still a long way from the scale needed to make a meaningful dent in global emissions.

In this article, we break down how it works, where it currently stands in terms of technological maturity, what it costs today and where costs might go, and what role it could play within the European certification framework that recently came into force.

What is DACCS, and why does it matter for the European market?

DAC (Direct Air Capture) refers to the process of pulling CO₂ directly out of the atmosphere using dedicated industrial equipment. When the captured CO₂ is then permanently stored — typically in deep geological formations — the process is more precisely called DACCS (Direct Air Carbon Capture and Storage), and it’s this configuration that produces verifiable, long-lasting carbon removals.

On the regulatory side, DACCS now has a well-defined place in the European landscape. Regulation (EU) 2024/3012 — the Carbon Removal Certification Framework (CRCF) — came into force on 26 December 2024 as the EU’s first voluntary framework for certifying carbon removals. DACCS is listed among the technologies eligible for certification as a permanent removal method: it can generate certified carbon credits, provided it meets strict quality criteria around measurement, additionality, and storage durability.

The first DACCS-specific certification methodologies are expected during 2026, with the first certified units to follow. The European Commission has already begun work on an EU Buyer’s Club: a platform designed to pool demand from companies and institutions looking to purchase certified carbon removal credits.

How it works: from the air to underground

The direct air capture process works in two main stages.

1. Capture

Large volumes of air are drawn through modules containing either solid filters or liquid chemical solvents that selectively bind CO₂ molecules. The scrubbed air is released back into the atmosphere, while the concentrated CO₂ is collected and compressed. This is the most energy-intensive part of the entire process: because CO₂ makes up only about 0.04% of the air, separating it out is far more demanding than capturing it from industrial flue gases, where concentrations can be tens of times higher.

2. Storage

The captured CO₂ is injected into deep geological formations — depleted gas reservoirs, saline aquifers — where it remains stably trapped for thousands of years. This is the configuration recognised by the CRCF as permanent removal and eligible for certified credits. Alternatively, CO₂ can be mineralised into basaltic rock (as happens in Iceland through the Carbfix project) or used as a feedstock for synthetic fuels — but only geological storage provides the permanence required for certification.

Where the technology stands: maturity levels (TRL)

DACCS has moved beyond the purely experimental stage, but it’s not yet a mature technology at industrial scale globally. The clearest way to situate it is through the Technology Readiness Levels (TRL) — the standardised scale running from 1 (research concept) to 9 (fully commercial and operational).

For context: a commercial solar PV installation sits at TRL 9, offshore wind at TRL 8–9. DACCS is at a similar stage to where offshore wind was in the mid-2000s — technically proven, but still expensive and with very little installed capacity. How quickly it climbs the remaining levels will depend heavily on public funding and market demand.

Costs: where we are and where we could go

Cost is currently the biggest barrier to DACCS deployment. The drivers are many: energy prices (the dominant factor for liquid solvent systems), the cost of solid sorbents, plant scale, and cost of capital. Estimates vary widely depending on methodology, but the overall picture is fairly clear.

An independent analysis by ETH Zurich (Sievert, Schmidt & Steffen, 2024) estimated that, at 1 billion tonnes of cumulative installed capacity, costs could settle between $230 and $540 per tonne — a wider range than the more optimistic projections, but still confirming the downward trend. The bottom line is that costs will fall, just not as fast as many have hoped: DACCS learning curves appear to be slower than those seen in technologies like solar PV.

DACCS will get cheaper. But the road is longer and harder than it’s often made out to be.

How much CO₂ can DACCS actually remove? Current capacity and outlook

The gap between ambition and today’s reality is enormous. DACCS currently contributes next to nothing to global CO₂ removal: the handful of operational plants work at the scale of thousands of tonnes per year, while the volumes needed for a net-zero pathway are measured in billions.

To put this in perspective: global annual CO₂ emissions currently exceed 37 billion tonnes. Even in the most optimistic 2050 scenario, DACCS would remove less than 1% of that. This doesn’t make the technology irrelevant — quite the opposite, it’s essential for offsetting emissions that can’t be eliminated at source — but it does confirm that DACCS cannot substitute for reducing emissions in the first place.

The challenges to scaling up DACCS 

DACCS is a promising technology, but it faces structural challenges that won’t solve themselves. Three in particular stand out.

Capital costs (CAPEX) are still very high

Building a DACCS plant requires significant infrastructure investment, and the technology hasn’t yet reached the economies of scale that would bring those costs down. The gap relative to point-source capture from industrial flue gases is a structural one: pulling CO₂ from air at 0.04% concentration requires vastly larger volumes and contact surfaces than capturing it from an industrial chimney where concentrations can reach 10–15%.

Operating costs (OPEX) are structurally elevated

 Running a DAC plant requires large amounts of energy — heat to regenerate solvents or sorbents, electricity for fans and compression systems. For the overall carbon balance of the process to be genuinely negative in CO₂ terms, that energy must come from low-emission sources. Affordable renewable electricity is therefore a prerequisite, not a nice-to-have.

Market demand is still limited

The carbon removal credit market is young, and today’s demand is concentrated among a handful of early-adopter buyers — large tech companies, thematic investment funds. The CRCF could change this dynamic by building trust and transparency, but broad uptake from European businesses is still a work in progress.

CRCF certification: a complex process that requires support

DACCS is the first technology for which the European Commission is developing a dedicated certification methodology under the CRCF — a meaningful signal that the regulatory framework is real and maturing. But certifying a carbon removal project is a detailed process, requiring careful management of operational milestones, in-depth technical documentation, and engagement with accredited verifiers.

At Kyklos Carbon, we’re building a platform specifically for carbon removal project developers — including DACCS — to streamline the entire certification journey: from managing operational milestones to producing the documentation needed to obtain verified carbon credits under the CRCF.

The platform is currently in development. If you’re managing or developing a carbon removal project and want to be among the first to test it, get in touch.

Conclusion

Direct Air Capture with geological storage isn’t the single solution to the climate crisis — but it is a necessary tool. It’s the only technology capable of removing CO₂ from the atmosphere with a limited land footprint, verifiable permanence, and no dependence on biological cycles. That’s precisely why the CRCF has placed it among the first methodologies to be developed.

The challenge now is to scale it from the kilotonne level — where it sits today — to the megatonne level, driving costs down through economies of scale and continued innovation. It’s a long road, but it’s already underway.

Source:

• Regulation (EU) 2024/3012 – Carbon Removal Certification Framework (CRCF), Official Journal of the EU, 6 December 2024.
• European Commission / JRC (2024). Technology Readiness Levels and cost projections for DACCS in Europe.
• IEA (2022). Direct Air Capture 2022 - Executive Summary.
• IEA - Direct Air Capture (Energy System, updated page).
• Sievert K., Schmidt T.S., Steffen B. (2024). Considering technology characteristics to project future costs of direct air capture. Joule. [ETH Zurigo] - via ScienceDaily.
• Belfer Center, Harvard Kennedy School (2023). Prospects for Direct Air Carbon Capture and Storage: Costs, Scale, and Funding.
• European Commission - DG CLIMA. Carbon Removals and Carbon Farming (official page).