‘We Create Electricity From Nothing’: Scientists Discovered a New Renewable Energy Source Based on Humidity by Accident

Capturing moisture and converting it into electricity is not only possible, it's also getting easier.

'We created electricity from nothing': The new renewable energy source based on humid air, the result of a coincidence.
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You don't need ingenuity to achieve scientific breakthroughs. Sometimes you just need sheer luck. That happened to Jun Yao, a University of Massachusetts Amherst professor working on a moisture sensor. The project wasn’t particularly complex, but his findings were. While working on the device, one of his students student forgot to plug it in. However, to the amazement of Yao and his colleagues, the array of microscopic tubes and nanowires continued to generate a faint electrical signal.

Since then, they’ve continued their research, achieving promising results.

Generating electricity from “nothing.” The expression comes from the University of Massachusetts, which in early 2020 boasted of the breakthrough its researchers had achieved. They developed a device that uses a natural protein to generate electricity from “nothing,” a gimmicky formula that refers to something much more conventional but just as surprising: the humidity in the air.

The researchers published their work in Nature, where engineer Yao and microbiologist Derek Lovley explained how they made a device with protein nanowires grown from Geobacter sulfurreducens. The name of their contribution? Air-gen. They generated an electric current by connecting electrodes to the micron-thin channels.

A new source of energy? “We are literally creating electricity out of nothing,” Yao celebrated. The nonpolluting technology offered a low-cost, renewable solution that could generate electricity indoors and in particularly arid areas such as the Sahara. Even then, his goal was to go further and take his invention to a commercial scale, developing devices capable of powering small electronic devices such as smartwatches, sensors designed to monitor users’ health, or even smartphones.

What’s new now? The University of Massachusetts team continued their work and published a paper published in Advanced Materials journal last year. Their study demonstrated that one can turn almost any material into a device capable of harvesting electricity from moisture. To do this, they went from using nanowires to tiny perforations. The key is to incorporate nanopores with a diameter of less than 100 nanometers, or less than one thousandth of a human hair.

“What we realized after making the Geobacter discovery is that the ability to generate electricity from the air—what we then called the ‘Air-gen effect’—turns out to be generic: Literally any kind of material can harvest electricity from the air, as long as it has a certain property,” Yao explains. He points out that his idea, although “simple," can “[open] all kinds of possibilities.”

But… how does it work? “Air contains an enormous amount of electricity,” the professor of electrical and computer engineering stated before using similes to explain his proposal. “Think of a cloud, which is nothing more than a mass of water droplets. Each of those droplets contains a charge, and when conditions are right, the cloud can produce a lightning bolt—but we don’t know how to reliably capture electricity from lightning. What we’ve done is to create a human-built, small-scale cloud that produces electricity for us predictably and continuously so that we can harvest it.”

The logic. The “cloud core” is the work Lovley and Yao developed when they hinted at the possibility of a material made of protein nanowires grown with Geobacter sulfurreducens. They use 100 nm nanopores because that’s the “mean free path” of water molecules, the distance a molecule travels before colliding with another similar molecule. They propose using a layered whole of nanopores that allow water molecules to pass from top to bottom. An imbalance is created since the first layer would be “bombarded” by more charge-carrying molecules, like in a cloud.

What possibilities does it offer? In 2020, researchers were already pointing to the potential use cases of Air-gen, both in renewables and in the design of specific medical devices. Their approach three years later is just as ambitious: “Moisture in the air is a large reservoir of sustainable energy that, unlike solar or wind power, is continuously available,” the researchers stated in an article in Advanced Materials. Scientists can also apply their proposal for capturing energy to a “wide range” of materials if they have nanopores that allow water to pass through.

“We are opening a wide door to clean electricity from the air,” Xiaomeng Liu, one of the article’s authors, says. The University of Massachusetts also points out that humidity is always present, which would make it possible to obtain energy 24 hours a day, seven days a week. Moisture would also solve one of the disadvantages of renewable energy sources such as wind or solar: intermittency, which leads to mismatches between when the systems produce energy and when it’s needed.

Are they the only ones working in this field? No. Hygroelectricity, or electricity from humidity, has attracted other researchers who’ve also made progress. Catcher, for example, is a project supported by the European Union to convert humidity into electricity. Svitlana Lyubckyk and her sons, the driving force behind CascataChuva, are involved in the initiative. “We developed a revolutionary technological solution for producing electrical energy through direct conversion of the humidity adsorption energy by elaborating a highly innovative ‘atmospheric humidity to electricity’ converter device,” they explain on their website.

Imagen | Veronica Alvarado (Unsplash)

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