Direct air capture (DAC) is touted as a potential contributor to climate change mitigation and the achievement of net-zero emission targets, including in nations like Canada. Recent research by faculty affiliated with Carleton University’s Sustainable Energy program shows the extent to which ambient environmental conditions, including temperature, pressure, carbon dioxide concentration, and relative humidity, influence the capacity factor, water losses, and cost of these plants in Canada.
The open-access research, published in Communications Earth & Environment, shows that a DAC plant constructed in Ottawa would be expected to capture only 55% of the carbon dioxide that its nameplate capacity would suggest. Plants in colder climates, like Alberta, which is betting on carbon dioxide removal as its key climate strategy, fare even worse, with a plant in Calgary capturing 45% of its expected capture. Colder climates necessitate the shut down and restart of these large, complex, and tightly integrated plants, further damaging capture performance. Plants in warmer climates perform well, but the water losses in those locations are extremely highly.
The findings in this study can be used to calibrate policy maker expectations, investment decisions, and policy support for DAC. They can also be used by engineers as they refine and optimize plant design to maximize capture.