posted on 2024-05-01, 07:32authored byXuqing Cai, Mark A. Coletti, David S. Sholl, Melissa R. Allen-Dumas
The cost and efficiency of direct air capture (DAC) of
carbon dioxide
(CO2) will be decisive in determining whether this technology
can play a large role in decarbonization. To probe the role of meteorological
conditions on DAC we examine, at 1 × 1° resolution for the
continental United States (U.S.), the impacts of temperature, humidity,
atmospheric pressure, and CO2 concentration for a representative
amine-based adsorption process. Spatial and temporal variations in
atmospheric pressure and CO2 concentration lead to strong
variations in the CO2 available in ambient air across the
U.S. The specific DAC process that we examine is described by a process
model that accounts for both temperature and humidity. A process that
assumes the same operating choices at all locations in the continental
U.S. shows strong variations in performance, with the most influential
variables being the H2O gas phase volume fraction and temperature,
both of which are negatively correlated with DAC productivity for
the specific process that we consider. The process also shows a moderate
positive correlation of ambient CO2 with productivity and
recovery. We show that optimizing the DAC process at seven representative
locations to reflect temporal and spatial variations in ambient conditions
significantly improves the process performance and, more importantly,
would lead to different choices in the sites for the best performance
than models based on a single set of process conditions. Our work
provides a framework for assessing spatial variations in DAC performance
that could be applied to any DAC process and indicates that these
variations will have important implications in optimizing and siting
DAC facilities.