It is estimated that some 2.2 billion people currently lack access to safe, clean drinking water, and scientists predict that this number could increase as rising sea levels impact on freshwater bodies. In an attempt to resolve this dire situation, researchers at Alphabet’s “moonshot factory” have been investigating the potential of solar-powered devices that pull water from the air, which they say could provide clean water to a billion people around the world.
In a new study in the journal Nature, researchers from the Alphabet-owned company X explain that atmospheric water harvesters with a solar collection area of 1 to 2 meters squared could to produce as much as 5 liters (1.3 gallons) of water per day. However, this level of performance is only possible under certain conditions, and requires sufficient sunlight and temperature, as well as a relative humidity of at least 30 percent.
This means that while the device is likely to be highly useful in tropical climates, it is unlikely to meet the needs of those living in arid environments. According to the study authors, though, the majority of people facing water insecurity live in either sub-Saharan Africa or the Ganges River Valley in India, where conditions are conducive to the use of such equipment.
Using Google Earth Engine, the researchers pulled average weather data from locations around the world that are impacted by water challenges and cross-referenced this with population statistics in order to determine the potential utility of their device. Results indicated that 1 billion people without reliable access to clean water currently reside in regions where the climate allows for the use of such solar-powered apparatuses.
“Here we show that AWH [atmospheric water harvesting] could provide SMDW [safe managed drinking water] for a billion people,” write the authors. “Such a device could meet a target average daily drinking water requirement of 5 liters per day per person.”
In addition to studying the potential of a variety of different devices, the team also built their own prototype, which was designed to be affordable to people living off $2 to $8 per day. Consisting of vacuum-formed parts, the device has been refined over the past three years, and the team at X believes it could soo be capable of generating water at a cost of 10 cents per liter.
However, the engineers behind the project hope to reduce this cost to just 1 cent per liter, and have therefore made their design open-source so that others can improve upon the current prototype. The main challenge, say the study authors, lies in developing more cost-effective manufacturing processes for sorbent materials.
Ultimately, the researchers want to develop a device that can generate water for next to no cost in all climates, including dry environments with very low levels of relative humidity. Meeting this challenge, they say, could provide a feasible solution to one of the greatest threats facing a significant proportion of the world’s population.