Exploring Alternative Opportunities for Direct Air Capture Technologies

Licentiatavhandling, 2025

The 2050 net-zero emissions target envisions in part compensating for emissions through the use of carbon dioxide removal (CDR) technologies. Among these, direct air capture (DAC), which captures CO₂ directly from the air rather than from point sources, has gained attention due to its scalability and potential for placement near storage sites. However, as a novel energy-intensive technology requiring large-scale deployment, DAC remains a costly option for CO₂ removal. Non-classical deployment opportunities for DAC technologies could lower costs.
While the technologies developed for DAC are different from those developed for capturing carbon at point sources, one possibility would be to deploy the former at point sources with dilute flue gas streams. Another option is to consider deploying DAC technologies near energy sources. This study aims to evaluate two such alternative deployment opportunities for two commercialized DAC technologies: Temperature Vacuum Swing Adsorption (TVSA) and Alkaline Absorption with subsequent calcium looping (ALK-ABS). The analysis includes a cost assessment of using DAC for capturing CO₂ from low-concentration flue gas streams and for integrating DAC into combined heat and power (CHP) plants to use their excess heat.
We find that, for capturing CO₂ from dilute flue gas streams (0.5-4%), monoethanolamine (MEA)-scrubbing, developed for capturing carbon from point sources, demonstrates better economic performance than TVSA and ALK-ABS. Based on the levelized cost of CO₂ avoidance, at CDR price of 400$/tCO2 purchase of CDR credits is more economical than onsite capture for flow rates below 500t/h for CO₂ concentrations below 2.6%.
The integration of DAC into CHP plants presents a viable business opportunity, particularly in the emerging CDR market. Our findings indicate that at CDR price of 615 €/tCO2, CDR could contribute up to 80% of the net cash flow for CHP plants in the future, with DAC alone accounting for 12% of the total net cash flow. Estimates suggest that integrating DAC into CHP plants across Sweden could achieve approximately 33% of the country's national CDR target.