So, yeah, let’s use solar energy to generate Hydrogen from water.
But, wait. Many places don’t have water to spare. Burning drinking water for fuel may not be an ideal solution, e.g., in a desert. Plenty of sun, no water.
This summer, researchers in Australia report a system that harvests water from the air to generate Hydrogen [1] . They use a sponge filled with hygroscopic solution, i.e., a chemical that absorbs water from the air. Current from a photovoltaic cell or wind turbine drives a reaction to split the water and collect Hydrogen which can be used as fuel. It’s totally passive, relying on ambient air flow.
Cool!
This technique works even if the air is dry—some chemicals work at 4% humidity.
The researchers calculate that the technique generates 745 L of hydrogen per square meter a day, “enough to heat a home” [2].
Even cooler!
Everything depends on finding the best hygroscopic chemicals, something that is cheap, safe, and reliable. I’ll note that this might be combined with other absorbing technologies, to harvest drinking water or achieve passive cooling.
And, of course, this might be built into structures or vehicles. It would be neat for the roof of a house or car (or dirigible!) just suck water out of the air to generate fuel! (And remember, human occupants are emitting humidity all the time!)
I want it!
- Jining Guo, Yuecheng Zhang, Ali Zavabeti, Kaifei Chen, Yalou Guo, Guoping Hu, Xiaolei Fan, and Gang Kevin Li, Hydrogen production from the air. Nature Communications, 13 (1):5046, 2022/09/06 2022. https://doi.org/10.1038/s41467-022-32652-y
- Prachi Patel, Engineers Make Green Hydrogen From Air, in IEEE Spectrum – Energy, September 12, 2022. https://spectrum.ieee.org/engineers-make-green-hydrogen-from-air
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