Scientists generate electricity from moisture in the air

American scientists at the University of Massachusetts Amherst have developed a device that makes it possible to generate electricity from moisture in the air via a natural protein.

Electrical engineer Jun Yao and microbiologist Derek Lovley call their device the Air-gen, short for “air-powered generator.” According to the scientists, their device literally makes electricity from air. It is about generating a clean and cheap form of energy that, according to the researchers, can also be used in the desert and even in buildings. They argue that existing moisture-based energy-harvesting technologies can only produce short current pulses because they lack a sustained conversion mechanism.

Their invention is based on a thin film of nanowires with proteins, the wires being thinner than 0.01 mm. These electrically conductive wires are produced on the basis of the bacterium Geobacter sulfurreducens. The bottom of the film rests on one electrode, while another, smaller electrode occupies only part of the film. The layer absorbs water vapor from the atmosphere. The combination of the electrical conductivity and chemical properties of the protein nanowires, supplemented by the fine pores between the nanowires, create conditions for the generation of an electrical current between the two electrodes. The device generates a voltage of approximately 0.5V across the 7 micrometer thick film, with an electrical current density of approximately 17 microamperes per square centimeter.

Their current Air-gen device provides enough power for small devices, but they expect to be able to scale their invention commercially quickly. The ultimate goal is to deploy the technology in large-scale systems, such as wall paint to power homes and buildings. The scientists are also thinking of stand-alone generators that can supply electricity to the electricity grid purely on the basis of the air.

According to Yao, it will be possible to make larger systems once the production of the nanowires is on an industrial scale. Lovley has since further improved the biological capabilities of Geobacter sulfurreducens, in order to be able to develop protein nanowires faster and on a larger scale, so that the amount of available nanowires no longer forms an obstacle.

The research is published in the scientific journal Nature, under the title Power generation from ambient humidity using protein nanowires.