The National Energy Technology Laboratory (NETL) has completed the first successful field test of direct air capture (DAC) technology at the National Carbon Capture Center (NCCC) in Wilsonville, Alabama. The test advances the development of a cost-efficient system to reduce atmospheric levels of carbon dioxide (CO2).
“Results of the field test, which was completed in July at the NCCC in Wilsonville, Alabama, advanced the development of a system that has potential to lower the cost of DAC while reducing atmospheric levels of CO2, a greenhouse gas,” said Naomi O’Neil, NETL federal project manager.
DAC technologies process air directly from the atmosphere rather than targeting CO2 emissions from point sources such as power plants and industrial facilities. As an emerging solution, DAC plays a key role in US strategies to address both current and legacy emissions, supporting a Net Zero emissions economy by 2050.
The field test was led by the Southern States Energy Board (SSEB), with $2.5 million in federal cost-share funding for the Direct Air Capture Recovery of Energy for CCUS Partnership (DAC RECO2UP) project.
The solid-amine CO2 adsorption-desorption cycle used at NCCC. Once the technology binds sufficient quantities of CO2, its honey-combed shaped monoliths are exposed to vacuum and steam heat to desorb the CO2 from the solid sorbent. ©NETL
Other collaborators included Aircapture, a Berkeley, California-based company specialising in modular DAC systems designed for on-site CO2 integration into industrial processes.
“The field test not only yielded data that demonstrated Aircapture’s technology can lower the cost of DAC, it also advanced the research to a technology readiness level (TRL) 5 and produced a CO2 stream of 95% purity, which is a concentration needed to transport CO2 for sequestration in the subsurface or use it as a feedstock to manufacture chemicals and other value-added products,” O’Neil said.
The test employed a solid amine sorbent-based DAC system, which operates on a CO2 adsorption-desorption cycle. The system uses honeycomb-shaped monolithic contactors infused with polyethylenimine polymers that capture CO2 from ambient air. After enough CO2 is adsorbed, vacuum and steam heat desorb the gas, creating a 95%-pure CO2 stream suitable for storage or industrial use.
The project involved the installation of three skids: one for CO2 adsorption/desorption, another for energy recovery and steam production, and a third for CO2 compression and purification. Over 3,300 operational hours, the system completed 137,000 cycles, achieving an operational uptime of 94%.
The Department of Energy (DOE) has allocated $3.5 billion under the Bipartisan Infrastructure Law to establish four DAC hubs across the country. These hubs will integrate DAC systems with CO2 storage and utilisation infrastructure, fostering large-scale deployment.
