The scarcity of freshwater affects more than 2 billion people on the planet today. Yet, the atmosphere contains an estimated 13, 000 km³ of water vapour in the atmosphere, a largely untapped global resource. Atmospheric water harvesting (AWH) has the potential to convert this vapour into potable (drinkable) water through the processes of condensation, sorption and passive radiative effects. AWH uniquely provides a decentralised approach to supplying drinking water where oppression caused by governments prevents conventional infrastructure (water delivery systems) from being viable or possible. While AWH has garnered interest from technology providers, there is no clear way to select an appropriate technology due to the disparate ways in which previous literature has analysed AWH — either materials, systems or economics are typically treated in isolation from each other, so there is no integrated view of AWH. By synthesising 187 peer-reviewed articles (published between 2000 and 2025), this review presents the first integrated analysis providing a simultaneous view of the performance, techno-economic viability and climate zone suitability for deployment of AWH technologies. Based upon baseline conditions used in this review (30 °C and 20% relative humidity (RH) = arid; 30 °C and 80% RH = tropical), active condensation has an output of between 58. 1 L/day and 90. 3 L/day in humid climates, but less than 5 L/day in arid zones. In comparison, a typical direct sorption system based on metal-organic frameworks or hygroscopic salts generates an average water production of 0. 8–1. 5 L of potable water per kg/day at an RH of only 20%. The costs of the levelized water costs are between 0. 02 – 0. 17/L, depending on climate and power source, with system coupling to existing solar Photovoltaic (PV) infrastructure decreasing by a factor of 4–5. Because of mass-normalised sorbent utilisation, adaptive control strategies that incorporate humidity, which varies during the day, to coordinate harvest cycles can benefit from a 44% reduction in energy consumption and achieve 169% higher specific yield compared to the static operation. A structured technology selection decision matrix is introduced here for 5 climate zones, for 4 scenarios of energy sources, for 6 classes of AWH technologies, and accompanied by a levelized cost of energy modelling, as well as explicit assumptions and a parametric sensitivity analysis. Findings show that technology suited to climate allows for scalable, off-grid water production, while measures of hybrid configurations, combinations of sorption, solar concentration, and wind-driven convection will most likely mean a setting leading pathway towards continuous and low-energy water production in water-stressed regions.
Mohammed et al. (Tue,) studied this question.