Direct air capture is now considered an essential part of the portfolio of technologies that can enable us to limit global warming to acceptable levels. Apart from geological storage of the product CO₂, it can also be used for the manufacturing of carbon neutral chemicals. CO₂-capture from air is challenging because the low CO₂ concentration requires huge amounts of air to be moved through the contactors and the thermal release of CO₂ from the capture agents will require significant amounts of energy.

 

Here we provide a technical development roadmap by which liquid-absorbent based CO₂-capture processes, the leading technology in CO₂-capture, can be used for air capture. This is advantageous as one can build upon the existing and standard design and engineering practices, which will facilitate development and deployment. The technical roadmap is based on the following staged approach:

This approach reveals that CO₂-capture costs below $100/t CO₂ are achievable.

The outcome of the technical roadmap is used for an estimate of costs to produce methane from CO₂ and H₂, which results in a renewable fuel that could be exported using the existing infrastructure that can compete with export of liquid hydrogen.