INTERVIEW: RepAir targets modular electrochemical CO2 capture to cut energy use

Startup RepAir Carbon is developing a modular electrochemical approach to carbon capture designed to work at low CO2 concentrations, expanding the range of industrial applications where carbon capture and storage could be deployed, and dramatically lowering energy use for the capture process.

The technology uses a solid-state electrochemical cell to capture CO2 at concentrations below 5%, where more established technologies can struggle.

"The technology is at the crossroads between batteries and fuel cells, but applicable to carbon capture," RepAir Vice President for Strategy & Growth Jean-Philippe Hiegel told Platts in an interview.

The electrochemical process uses one electron per molecule of CO2 removed, with flue gases flowing over an electrode. "We try to leverage the precision of electrochemistry," he said.

The technology uses an anion-exchange membrane to bind CO2 molecules in a three-layer cell, where a redox reaction binds CO2 to hydroxide ions.

The lower concentration capability could be relevant for sectors like aluminum, where smelter off-gas CO2 concentrations are around 1%, Hiegel said.

The company is working with aluminum producers on feasibility studies to evaluate deployment at scale for process emissions, he said.

In a test at 1% CO2 concentration in Norway, the system used 450 kWh/metric ton CO2 captured and achieved a 90% capture rate, Hiegel said.

Traditional liquid solvent capture systems typically require 2-3 MWh/mt CO2 captured and generally work down to 5% CO2 concentrations, requiring a lot of heat with high energy intensity.

"That is where the energy intensity is undoing the economics" of conventional carbon capture, Hiegel said. "We remove heat from the equation."

RepAir is deploying 1,000 square centimeter cells and aims to install a commercial stack in 2026, Hiegel said.

"We believe this is now commercial scale," he said.

Larger capture units can be constructed, with modules stacked both vertically and horizontally up to 25 meters high. "We scale by modularity," Hiegel said.

He said the next step towards commercialization was to de-risk the technology, deploying a stack on site.

The company has secured Eur12.5 million ($14.3 million) in blended funding from the European Innovation Council and EIC Fund in 2025, comprising Eur2.5 million in grant funding and Eur10 million in equity investment.

Platts, part of S&P Global Energy, assessed nearest December EU ETS CO2 allowances at Eur81.17/mt ($93.03/mt) on July 15.