A California-based team of designers has built a shipping container that can harvest enough water from the air to satisfy 100 people’s daily needs.

Architect David Hertz and his colleague, Rich Groden, recently received $1.5 million as the winners of the Water Abundance XPrize, a competition that aims to help alleviate global water shortages.

About 2.1 billion people around the world lack immediate access to clean drinking water, and the US Defense Intelligence Agency estimates that water requirements will exceed supplies by 40% shortage by 2030.

The XPrize competition was created in 2016 to address that problem by rewarding designers who come up with new ways to pull fresh water out of thin air.

Nearly 100 teams entered this year’s competition, and two finalists were asked to test their devices last month. The finalists had to show that their inventions could extract at least 2,000 liters of water per day, at a cost of less than 2 cents per liter.

According to a press release, Hertz and Groden’s team, called Skysource/Skywater Alliance, won the grand prize because it “demonstrated the greatest ability to create decentralized access to water.”

How the system works

Skysource/Skywater Alliance’s creation is called “WeDew,” which stands for wood-to-energy deployed water system. It’s a combination of two existing devices. The first, Skywater, is a generator that imitates a cloud. Skywater, co-invented by Groden, cools warm air and stores the resulting condensation inside a tank. Water in the shipping container’s tank can then be accessed via a tap or water fountain.

The condensation process requires electricity, so the architects also incorporated a biomass gasifier into their system as a low-cost energy source, as Fast Company reported. Gasifiers can take in organic material and vaporize it to produce a gas mixture of hydrogen, carbon dioxide, and carbon monoxide that serves as a fuel.

A gasifier can be filled with various types of biomass, including coconut shells and pieces of pine trees. The vaporization creates heat and humidity, which help the water-gathering device operate efficiently. In addition, the gasifier produces biochar as a byproduct, a carbon-rich substance that can be put in soil to help plants grow.

“It’s a carbon-negative technology,” Hertz told Fast Company. “I think the future of technologies is going to be moving to this restorative, regenerative model that actually helps to repair the damage we’ve done.”

A race to pull water from the air

The new XPrize winner joins a growing number of teams working on devices that can produce water from the air. This year’s runner-up, Hawaii-based JMCC WING, received $150,000 for a wind-energy system that extracts water from the atmosphere.

Researchers at the University of Akron in Ohio also recently began developing a prototype water harvester that could produce up to 10 gallons of drinking water every hour.

Dr. Josh Wong, a professor of mechanical engineering at the University of Akron, previously told Business Insider that he hopes the water harvester can be used in regions where water is scarce. Wong presented his findings at an American Chemical Society meeting in August, and is working to secure enough funding for developing a prototype. He said his design would be cheaper than other similar concepts, and he expects it to be smaller as well — it may take the form of a backpack.

Earlier this year, scientists at the University of California, Berkeley, also developed a device that can harvest fresh water from the air using just the sun’s heat. The group tested a prototype in Arizona and published the results of their trial in the journal Science Advances. Their device can yield about 7 ounces of water in 24 hours, which isn’t enough to keep someone hydrated. But the scientists said in a video that scaling the system up would be relatively easy.

Another startup, Zero Mass Water, uses solar energy to produce heat and harvest liquid water from vapor in the air. The startup launched its first product, Source, in 2015, and it has since installed devices in more than a dozen countries. Source became available in the US late last year.

Hertz and Groden, meanwhile, are planning to start teaming up with nonprofits to implement their prize-winning technology all over the world, according to Fast Company. They said the shipping containers could one day help provide drinking water in areas hit by natural disasters.