Florida contractor Richard Groden had been hired to do a renovation at the world famous Cotton House on the tiny island of Mustique. When his team got there, the island was dry – there was no water. But noticing how much condensate the air conditioners produced, and knowing that the Incas and Aztecs had gotten water from the sky, he was inspired to update that ancient technology by building a machine that makes water from air.
“We’re harnessing an ancient technique, but doing it in a new, more efficient way,” he said. “This is something the Incas and Aztecs were doing. They would string long nets up in the mountains to collect the dew from the fog and this water would drain down into troughs which they would bring down to their cities.”
He created the Island Sky company and has been making the machines since 2004. “Our water systems can be fully powered by solar panels and passively generate clean water, making it an ideal off-the-grid solution for green building,” he says.
The Skywater ESU-20 can deliver up to 900 gallons of pure drinking water daily, running off a 30-kilowatt electric diesel generator. “After the Super Typhoon Haiyan devastated the Philippines [in 2013] our machines were set in place and they immediately began making water for the thirsty, homeless victims of the storm.”
On the other side of the USA, architect David Hertz also had been thinking about atmospheric water, as California was into its fourth year of drought. One day in 2014, a client told him about a machine that created water from the air. So he got in touch with Groden, who flew out to visit him in Venice Beach.
“It was four years into the California drought, and many fountains and showers near the beach, key sources of water for the local homeless population, had been shut off,” as the New Yorker told the story. “Groden and Hertz hatched a plan: Groden would donate a Skywater 150 to Hertz—one of about 20 currently in use—and Hertz would demo it to prospective clients while helping to alleviate his neighborhood’s water shortage.”
Hertz installed a 150-gallon a day machine in his office to support a solar-powered bottle filling station in the alley. “So the idea that I could just make water from the air and give it away for free, was really a compelling notion and expanded on that idea of the democratization of our common good,” Hertz said. The filling station also produced enough water to support 88 urban farm boxes managed by the nonprofit Community Healing Gardens.
The farm boxes are watered by teenagers who have aged out of foster care and are on the streets, through a nonprofit called Safe Place For Youth, “So the idea is that we’re taking the light and making electricity and then using electricity to make water and give water away and create jobs and help feed people is all part of this energy-water-food nexus that is so, so needed.”
Skywater and Skysource put their heads together and entered the $1.5 million Water Abundance XPrize, which they won in 2018. The prize, funded by the Tata Group and Australia’s Aid Program, challenged teams to alleviate the global water crisis with energy-efficient technologies that harvest fresh water from thin air.
Out of 97 entries from 27 countries, theirs was the only one to meet all the criteria: Produce at least 2,000 liters (528 gallons) of water a day, at a cost of less than 2 cents per liter and run entirely on renewable energy.
“All we’re really talking about is very simple,” Hertz says. The Earth and its atmosphere are a closed system with a set amount of water that changes form as liquid, vapor, and ice. “There’s six times more water in the atmosphere than all the rivers on the planet,” he says. “The real challenge is how do you capture this available moisture?”
Their winning system, WEDEW (“wood-to-energy deployed water”), combines existing Skywater technology with a biomass gasifier which can be fuelled by anything from wood chips to coconut shells and which creates biochar that can be used for fertilizer. The system can also run on solar and battery power.
“We are creating a tropical climate in the box,” Hertz explains. “We use whatever is abundant in the region. In Asia, it’s rice husks and coconut shells. In Africa, wood and [agricultural] waste. In California, we have plenty of dead and dying trees, and agricultural waste such as nut shells in abundance.”
In 2020, Time listed WeDew among the magazine’s 100 best inventions. In 2022, it won the Cooper Hewitt—Smithsonian Design Museum National Design Award. In 2019 it won the Fast Company World Changing Ideas Award and in 2018, the World Technology Network World Technology Award.
The California Department of Forestry and Fire Protection is using WeDew in forests in northern California because of biochar’s fire-suppressing capability. In 2020, WEDEW and the UN’s World Food Program formed a partnership to bring the system to Uganda, Liberia and India. It also is discussing with the U.N. about how to serve island nations, where rising sea levels are causing saltwater incursion in fresh water.
Hertz envisions multiple WEDEW units being set up side-by-side in what he calls “Community Climate Resilience Hubs,” where “they’re in a steady state of self-reliance, but in the event of a disaster or drought, can be rapidly deployed to other locations … These will be particularly beneficial in the developing world where competition for resources, especially water, is a threat multiplier with increasing climate change.”
Unlike solar power, the biomass gasification process can run 24/7 and occupies a much smaller area than solar panels. And because biomass fuel is available almost everywhere for free from the leftovers of crop harvesting, forest thinning, brush clearing and natural disasters; it’s cheaper, more sustainable and less harmful to the environment than using diesel generators.
“Current water extraction approaches keep communities dependent on failing or non-existent infrastructures,” said XPRIZE. “It simply isn’t sustainable. But by integrating dehumidification, biogasification, and a reliance on sustainable energy, this new method of Atmospheric Water Extraction can go to scale and have impact now.” There has been tremendous interest from governments, universities, corporations, and investors who want to adapt and scale the Skysource/Skywater technology, giving communities around the world access to an abundant source of clean, drinkable water, it adds.
David Hertz’s Los Angeles oasis. New Yorker, Jul. 4, 2016
A tall, cool glass of air. Reasons to be Cheerful, Dec. 17, 2021
Malibu couple makes water from thin air. Malibu Times, Oct. 29, 2022
Creating water from thin air. X-PRIZE.