A techno-economic review of direct air capture of moisture processes: sustainable versus energy-intensive methods

One of the biggest challenges that the world faces today is the availability of fresh and potable water in arid, semi-arid, and deprived regions. This is a challenge that concerns not only economic development but also social development spanning several UN SDGs. This article presents a detailed critical and systematic review of the technologies for producing industrial and potable water. Emphasis is made on direct air capture (DAC) methods as the next frontier in sustainable water production against the backdrop of traditional energy intensive methods such as desalination. Comparisons using a variety of techno-economic, scale, geographic, and environmental metrics are carried out. While market reports suggest that investments and market value of DAC technologies will continuously rise, these data only extend the next 5–10 years. However, using this data, a projection was made by the authors on various scenarios leading to 2050. At 2030, best projections fall short of UN SDG 6 predictions for a four-fold increase (from 2020 levels) required to sustain populations. The review notes that DAC has the potential to be an attractive solution for the current water crisis (in some cases drought) experienced in various regions on earth. The report finds that while several moisture DAC technologies (e.g., fog and dew water harvesting) are currently being developed, they are only being implemented on small scales around the world—with huge implications for arid and deprived regions of the world.