(259d) The Cost Drivers of Solid-Based Direct Air Capture Technologies: Insights from Technoeconomic Analysis

Atmospheric carbon dioxide (CO₂) removal via Direct Air Capture (DAC) has received increasing attention in the last decade. The International Energy Agency (IEA) predicts in its Net Zero Emissions by 2050 roadmap that DAC installations are projected to capture about 85 million metric tonnes (Mt) of atmospheric CO₂ by the year 2030, with anticipations of an increase to roughly 980 MtCO₂ by 2050. However, this scale up is faced with considerable challenges, mainly the elevated costs associated with the capture process. These costs are driven from the utilization of advanced sorbent materials and the energy intensive nature of the sorbent regeneration processes. Thus, further investigations on novel materials and process design are needed to reduce the capture cost and enable DAC deployment at scale.

Here, an engineering design of a solid-based direct air capture (S-DAC) unit and a technoeconomic analysis (TEA) model are developed to assess the cost of capture using S-DAC technology and enable performing sensitivity analysis on the primary cost drivers influencing the economics of S-DAC operations. This TEA model incorporates a wide range of input variables pertinent to adsorbent materials, contactor functionality in both adsorption and desorption phases, and the overall process design. Key variables such as adsorbent capture capacity, selectivity, lifetime, regeneration temperature, and contactor design are examined as input parameters to obtain the overall cost of CO₂ capture. The TEA findings highlight the significance of adsorbent materials as the primary cost drivers in S-DAC systems. It is observed that various properties of the adsorbent materials induce differing degrees of influence on the overall capture cost and can drive the cost up to > 2,500 $/tCO₂. Moreover, it has been demonstrated that low-cost, durable and high-performing solid sorbent materials paired with contactor designs that facilitate high inlet air velocities alongside low pressure drops, has the potential to substantially reduce the cost of CO₂ capture.

The insights obtained from this work inform the significant role of the adsorbent materials performance and contactor design as substantial cost drivers of S-DAC technologies. These highlights are important to emphasize the need to develop novel and durable adsorbents and innovative contactor designs for efficient and economic S-DAC scale-up.