Sure, we all complain about the humidity on a sweltering summer day. But it turns out that same humidity could be a source of clean, pollution-free energy, according to a new study.

“Air humidity is a vast, sustainable reservoir of energy that, unlike solar and wind, is continuously available,” said the study, which was published recently in the journal Advanced Materials.

“This is very exciting,” said Xiaomeng Liu, a graduate student at the University of Massachusetts-Amherst, and the paper’s lead author. “We are opening up a wide door for harvesting clean electricity from thin air.”

In fact, researchers say that nearly any material can be turned into a device that continuously harvests electricity from humidity in the air.

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Air ‘contains an enormous amount of electricity’

“The air contains an enormous amount of electricity,” said Jun Yao, assistant professor of electrical and computer engineering at the University of Massachusetts-Amherst, and the paper’s senior author. “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 heart of the man-made cloud depends on what Yao and his colleagues refer to as an air-powered generator, or the “air-gen” effect for short.

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