US firm claims DAC cost breakthrough, but questions remain over scale

US-based carbon capture technology specialist Sustaera has claimed its system could reduce direct air capture costs by three to five times compared with conventional approaches, potentially bringing costs below $100 per tonne.

The company said the gains stem from improvements in energy efficiency and system design rather than a single step-change in chemistry.

“[Traditional] thermal technologies max out at around 40% efficiency,” said CTO Cory Sanderson. “We’ve recently achieved 90%+ efficiency, using far less capital than traditional thermal approaches.”

The efficiency figure refers to how much of the input energy is used directly to release CO2 from the sorbent, rather than being lost through heat transfer or system inefficiencies.

Conventional thermal DAC systems typically rely on indirect heating methods such as steam or kilns, which can result in substantial energy losses.

Sustaera instead uses a nano-structured, mineral-based sorbent combined with integrated electric heating. The material is engineered to have a high internal surface area, allowing CO2 molecules to bind more readily at low concentrations.

Electric resistive heating is then applied directly to the sorbent, reducing the need to heat surrounding equipment or large volumes of air.

This targeted approach is intended to lower overall energy demand and enable faster capture-release cycles.

Together, these factors could reduce both operating costs and capital intensity by shrinking equipment size and increasing throughput per unit.

However, the company has disclosed limited detail on the exact composition of its sorbent, describing it broadly as mineral-based and derived from abundant materials.

There are also trade-offs. Nano-structured materials can be sensitive to thermal cycling, moisture and oxidation, all of which are inherent to DAC operating conditions.

This can reduce sorbent lifetime and introduce replacement costs, which are a key variable in overall system economics.

As such, the claimed cost reductions depend not only on energy efficiency, but also on durability, electricity prices and system uptime.

The technology has so far been demonstrated at prototype scale, with the 90%+ efficiency figure reported from Sustaera’s laboratory in North Carolina. Independent validation and long-duration performance data have not yet been published.

This places the company’s progress closer to a technical milestone than a fully proven commercial solution.

Sustaera has secured early demand through advance purchase agreements with carbon removal buyers including Stripe and Shopify. These agreements commit funding for future CO2 removal, typically at small scale and above-market prices, to support the development of early-stage technologies.

However, such deals are not equivalent to project financing and do not guarantee that systems can operate at scale or at the lower costs being targeted.

The company said it is in advanced discussions with project developers, although no deployment timelines or project details have been disclosed.

The global CO2 removal market is projected to reach $100bn annually by the early 2030s, up from $2.7bn in 2023, according to Reuters, with engineered solutions such as DAC expected to account for a growing share if costs can be reduced.