Renewables are about to welcome a new member into the family of clean energy sources, thanks to researchers in Israel who have managed to generate a voltage using water vapor in the atmosphere.

The concept of humidity as a source of energy is based on a recent study in the journal Nature that found that electricity can be generated between dissimilar metals when placed under specific humidity conditions.

In the study, researchers wanted to develop a small low-voltage battery that charges from the humidity in the air. The concept is based on previous studies that discovered that water droplets have the ability to charge metal surfaces through friction and that certain metals can spontaneously build up an electrical charge when exposed to humidity.

In order to test these properties, the researchers from Tel Aviv University conducted an experiment to determine the voltage between two different metals exposed to high amounts of humidity. They found that voltage only developed when the relative humidity in the air rose above 60 percent – atmospheric conditions that are extremely commonplace across the globe, especially in the tropics.

Researchers think that humid air could be a source of electricity for surfaces with a voltage of one volt. While the voltage generated is extremely low, it can prove to be a viable renewable source of energy in developing countries, “where many communities still do not have access to electricity, but the humidity is constantly about 60 percent,” explains one of the study’s authors, Prof Colin Price.