China Creates 200 'Monsters' that Transform 100,000 Acres of Desert into Oasis Each Year

It’s a cruel irony that over 70% of the Earth’s surface is covered in water, but it’s undrinkable. Scientists at the University of Illinois Urbana-Champaign (UIUC) have now modeled the feasibility of a hypothetical system that can capture water vapor from above the ocean surface and condense it into fresh drinking water, at a large scale.

Water scarcity is an ongoing issue that’s projected to only get worse, as climate change makes dry areas even drier. The oceans, home to over 96% of all water on Earth, represents a huge potential reservoir, but desalination is a tricky prospect to scale up thanks to the toxic wastewater it produces.

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The team proposes that structures could be built several kilometers offshore to capture air rich in water vapor from above the ocean surface. That air can then be piped back to land and condensed in another unit. This fresh water could then be used for drinking, agriculture, or whatever else a region needs it for. The whole system, according to the scientists, could be powered by offshore wind farms and land-based solar panels.

The researchers evaluated 14 cities around the world, including Abu Dhabi, Rome, Los Angeles and Barcelona, analyzing how much water could feasibly be extracted based on the offshore atmosphere in those locations. This would involve building water vapor-extracting structures standing 100 m (328 ft) tall and 210 m (690 ft) wide.

Using a membrane distillation process, water is evaporated under low pressure through a heat pump condensation process. The vapor produced by heating the water then passes through the membrane.

Unlike reverse osmosis, where water with dissolved salts and other solids is forced through the membrane, this membrane only allows water vapor to pass through.

The pores in this membrane are larger than the pores in reverse osmosis membranes, so less pressure, and thus less energy is required.