A 300-square-centimetre electrochemical cell from RepAir Carbon averaged 0.83 megawatt-hours per tonne of CO2 captured from ambient air, according to peer-reviewed results published in Nature Energy.

The single-cell mark landed lower still. A manufacturable unit ran for more than 5,000 hours and reached 0.46 MWh per tonne by the end of the test cycle — less than a third of the energy that liquid-based direct air capture systems typically consume to release captured carbon.

RepAir, working with researchers at the University of Delaware, says those numbers anchor a cost trajectory from $566 per tonne at the current pilot scale to below $100 per tonne once production reaches battery-industry volumes.

What does the battery design change?

The cell sits inside RepAir's ElectraStack system. It captures and releases CO2 as the unit charges and discharges, using nickel hydroxide chemistry drawn from rechargeable batteries.

That electro-swing replaces the thermal swing that liquid DAC systems rely on today. Liquid systems running at scale consume 1.5 to 2.5 MWh per tonne of CO2, RepAir says — most of it burned as heat to strip CO2 from capture filters.

The Nature Energy paper validates the cell's energy draw across three separate trial formats:

• A 25 cm² laboratory cell tested independently by the University of Delaware captured CO2 from 400 ppm air at an average 1.15 MWh per tonne.
• A manufacturable single cell logged 5,000-plus hours at RepAir's facility and reached 0.46 MWh per tonne.
• A nine-cell stack of 300 cm² cells averaged 0.83 MWh per tonne with a pressure drop below 300 pascals.

That last figure matters for fans and blowers. Operators typically oversize ducting and blowers above 300 pascals of pressure drop, eroding the energy savings the cell delivers.

How low can the cost go?

RepAir maps a pathway from US$566 per tonne for the current pilot generation to below US$100 per tonne at volume. The cost curve borrows learning rates already absorbed by the battery industry.

A sub-$100 threshold would reset procurement budgets for cement, steel, and chemicals producers now trialling DAC. RepAir's sales pitch targets industrial emitters whose process CO2 resists electrification — sectors where voluntary carbon market credits have lost ground with compliance buyers.

Where does the technology sit in DAC?

Direct air capture pulls CO2 from the open atmosphere rather than from a flue stack. Electrochemical variants electrify the capture-release cycle, sidestepping the heat-driven release that dominates first-generation DAC plants.

RepAir's bet is that the same nickel hydroxide cell format can use automated battery production lines already in commercial operation. If so, capital cost falls with the same learning curve the paper uses for its cost model.

Who is buying it?

RepAir has not named commercial offtakers for ElectraStack output. The company opened a European office in Luxembourg earlier this year and expanded its partnership with C-Questra, a UK-based carbon project developer, to target industrial CO2 emissions across Europe.

What happens next?

The Nature Energy paper is the third-party technical confirmation RepAir says its customers demanded. The remaining commercial hurdle is whether automated battery production lines — already running at scale for other cells — can absorb the ElectraStack format.

"Operating cost is energy, and this paper settles that with peer-reviewed data," said Amir Shiner, CEO and co-founder of RepAir Carbon.

"Capital cost is whether the equipment can be built on automated production lines that already exist. That is what we are building now," he added.

The next milestone is a multi-stack pilot sized for industrial flue gas or ambient air service, with cost-per-tonne disclosures tied to specific deployment sizes. RepAir has not committed a date for that scale-up, nor has it disclosed where the next cell format will roll off a battery production line.