New green technology generates electricity 'out of thin air'

Researchers at the University of Massachusetts Amherst have created a gadget that harnesses atmospheric moisture and a naturally occurring protein to produce electricity. They believe this innovative technology might have a big impact on renewable energy sources, climate change mitigation, and medical advancements in the future.

According to a story published in Nature today, electrical engineer Jun Yao and microbiologist Derek Lovley of UMass Amherst have developed an air-powered generator, or "Air-gen," using protein nanowires that are electrically conductive and made by the bacteria Geobacter. By attaching electrodes to the protein nanowires in this manner, the Air-gen allows the naturally occurring water vapor in the atmosphere to be converted into electrical current.

Yao claims, "We are actually creating electricity out of thin air." "The Air-gen produces clean energy continuously." As Lovely puts it, "It's the most amazing and exciting application of protein nanowires yet." Lovely has spent the last thirty years developing sustainable biology-based electronic materials.

Yao's lab has created new technology that is inexpensive, renewable, and non-polluting. It can produce electricity even in the Sahara Desert and other regions with extremely little humidity. It offers a lot of advantages over other renewable energy sources like solar and wind, according to Lovley, because the Air-gen doesn't need wind or sunshine to function, and "it even works indoors."

The researchers clarify that all that is needed for the Air-gen gadget is a thin layer of protein nanowires that is less than 10 microns thick. An electrode supports the bottom of the film, and an electrode covering a smaller portion of the nanowire film is positioned on top. Water vapor from the atmosphere is absorbed by the coating. The parameters that produce an electrical current between the two electrodes are determined by the surface chemistry and electrical conductivity of the protein nanowires as well as the tiny holes that exist between the nanowires inside the film.

According to the researchers, tiny electronics can be powered by the current generation of Air-gen devices, and they anticipate commercializing the technology shortly. They want to build a compact Air-gen "patch" that can power wearable electronics, such smart watches and health and fitness monitors, in order to do away with the need for conventional batteries. In order to do away with the need for frequent charging of cell phones, they also want to produce Air-gens.

Yao states, "Building large-scale systems is the ultimate goal." The technique may be used, for instance, in wall paint that powers your house. Alternately, we may create independent air-powered generators that provide electricity outside of the grid. I have no doubt that we will be able to create massive systems that will significantly contribute to the production of sustainable energy once wire production reaches an industrial scale."

In an effort to further the useful biological potential of Geobacter, Lovley's team created a novel microbial strain that can mass generate protein nanowires more quickly and affordably. He claims that "we turned E. coli into a protein nanowire factory." "Protein nanowire supply won't be a bottleneck to developing these applications with this new scalable process."

They claim that the Air-gen discovery is the result of an uncommon multidisciplinary partnership. More than thirty years ago, Lovley found the Geobacter bacteria in the Potomac River silt. Later, his group found that it could create protein nanowires that were electrically conductive. Yao had spent years working as an electrical device engineer at Harvard University using silicon nanowires before moving to UMass Amherst. They teamed up to investigate the possibility of creating practical electrical devices using the protein nanowires extracted from Geobacter.

While working on sensor devices in Yao's lab, Ph.D. student Xiaomeng Liu made an unexpected discovery. He remembers, "I saw that the gadgets created a current when the nanowires were touched with electrodes in a particular way. I discovered that water was adsorbed by protein nanowires, creating a voltage gradient across the device, and that exposure to ambient humidity was crucial."

Yao's lab has created several more uses for the protein nanowires in addition to the Air-gen. Yao declared, "This is just the start of a new era of protein-based electronic devices."