New Star Trek-style device ‘harvests clean energy out of thin air’ 

Like the replicator in Star Trek: The Next Generation, a new clean energy prototype promises to work wonders out of nowhere.

The researchers call it Air gene, a mobile electricity-generating device that uses a network of protein nanowires to convert the ambient humidity in the air into contained, synthetic thunderstorms.

This “human-built, small-scale cloud,” these scientists said, can produce electricity “predictably and continuously” in a wider variety of conditions than sun-dependent solar cells or wind-dependent turbines.

The team hopes Air-gen will be scaled up for mass use around the world – in environments ranging from the Amazon rainforest to the Sahara.

In its ability to make something out of nothing, the device resembles the replicator (above) from Star Trek: The Next Generation, capable of producing almost anything from surplus junk.

“The air contains an enormous amount of electricity,” said the study’s lead author, Dr. Jun Yao of Massachusetts University Amherst. “Think of a cloud, which is nothing more than a mass of water droplets.”

“Each of those droplets contains a charge, and if the conditions are right, the cloud can produce a lightning bolt,” Dr Yao said, “but we don’t know how to reliably capture electricity from lightning.”

Yao’s Air gene solves this problem by mimicking the conditions of high-energy storm clouds and trapping that charged water vapor in a network of tiny nanoscale pores.

Fortunately, Yao said, many different materials can be used to extract energy from this technique.

“It only needs to have holes smaller than 100 nm (nanometers) — or less than one-thousandth the width of a human hair.”

In fact, when his team first started testing this technology three years ago, they used a specialized material of protein nanowires generated from a bacterial culture of Geobacter sulfur reducers.

Essentially, Yao and his team confirmed that they could continuously harvest electricity from a petri dish using their “Air gene effect.”

The 100-nm size is so important to the process, the team says, because it scales to what chemists know as the “mean free path” — the distance a single molecule of water vapor can float in the air before colliding with another.

With these tiny pores, the researchers realized they could create a buildup of electrical charge as water molecules passed through their nanotubes. The effect is almost like balloons generating static electricity when they are forced to pass through a tube of thick carpeting.

The Air-gen system essentially creates a charge imbalance as the top end of the pore system builds up a charge unlike the bottom end, just like the two sides of a battery.

“The idea is simple,” Yao said, “but it’s never been discovered before — and it opens up all sorts of possibilities.”

In this drawing of the Air gene device, the team’s thin film of tiny protein nanopores is sandwiched between a pair of electrodes. The top electrode is small enough to expose the top pores to the moist air, creating the positive and negative charge difference needed for a battery-like effect

The scientists made their Air gene device from a specialized material of protein nanowires, which they grew from the bacteria Geobacter sulfur reducers. Scanning electron microscopy shows the surfaces of the tiny protein nanotubes (above) on a scale of just a few micrometers (µm)

Unlike solar cells, which often require exotic and sometimes toxic advanced materials to capture the sun’s rays, Air-gen’s nano-pore system could be designed from a wide variety of more environmentally friendly materials.

“What we realized after making the Geobacter discovery,” Yao said, “is the ability to generate electricity from the air — what we then called the “Air-gene effect” — turns out to be generic.”

“Literally any kind of material can extract electricity from air, as long as it can be formed into the tiny pore system of 100 nm,” he said.

Yao and his team hope their ultra-modular and portable concept can be deployed around the world in a wide variety of conditions.

“You could imagine harvesters made of one kind of material for rainforest environments, and another for more arid areas,” Yao said.

And because humidity is not exactly an uncommon weather phenomenon, Air-gen harvesters could run 24/7, day and night, in almost any weather condition.

According to their estimates, as published this month in the Advanced Materials magazinethe devices could be stacked by the thousands and generate more than 1 kilowatt of power per cubic meter of space.

“Imagine a future world where clean electricity is available everywhere,” Yao said. “The generic Air-gen effect allows this future world to become a reality.”