Liquid solvent direct air capture’s cost and carbon dioxide removal vary with ambient environmental conditions

Abstract

Emission trajectories produced by integrated assessment models increasingly suggest that gigatonnes of carbon removal will be required to stabilize atmospheric greenhouse gas concentrations at safe levels. This can be accomplished using the direct air capture of carbon dioxide, among other technologies. Process models of these systems assume that they would operate at standard ambient temperature and pressure, when capture rates vary with ambient conditions, including temperature, relative humidity, and other factors. Here, we build an open-source model of a liquid solvent direct air capture technology and analyze its capture performance as a function of hourly varying ambient environmental conditions across Canada. We find that, in the cool climate considered, capture performance is degraded due to both varying environmental conditions and the intermittent operation that could result. Our findings can be used to calibrate policy and investment decisions, and to support engineers in making operational design choices. In Canada, the performance of liquid-solvent direct air capture plants degrades in cold climates, while in warm climates, the performance is boosted but requires increased use of water, according to an analysis that uses an open-source model that combines chemical processes and cost data.