The search for renewable energy sources, which include wind, solar, hydroelectric, geothermal and biomass, is equally crucial for scientists and politicians, given their enormous potential in fighting climate change.
Un new study Tel Aviv University published in Scientific Reports notes that water vapor in the atmosphere could serve as a potential renewable energy source in the future. Powering devices with water vapor batteries? Let's see.
It was conducted by Prof. Colin Price in collaboration with colleagues from the TAU Porter School of the Environment and Earth Sciences. It is based on the discovery that electricity materializes in the interaction between water molecules and metal surfaces. "We tried to capitalize on a natural phenomenon: electricity from water", explains prof. Price. “Electricity in thunderstorms is generated only by water in its different phases: water vapor, water droplets and ice. In just twenty minutes of development, the clouds can make us go from water droplets to huge electrical discharges, lightning, hundreds of meters long ”.
Building on this research, the team began trying to produce a tiny, low-voltage battery that only works with moisture in the air.
Tension in the air
Scientists conducted a laboratory experiment to determine the voltage between two different metals exposed to high relative humidity, while one is connected to earth. "We found that there was no tension between them when the air was dry", explains prof. Price. “But once the relative humidity rose above 60%, a tension began to develop between the two insulated metal surfaces. When we lowered the humidity level below 60%, the tension disappeared. When we conducted the experiment outside in natural conditions, we saw the same results ”.
“Water is a very special molecule: during molecular collisions it can transfer an electrical charge from one to the other. Through friction, it can accumulate a kind of static electricity ", says prof. Price. “We tried to reproduce electricity in the laboratory and found that different isolated metal surfaces accumulate different amounts of charge from water vapor in the atmosphere, but only if the relative humidity of the air is above 60%. This occurs almost every day in the summer in Israel and every day in most tropical countries ”.
According to Prof. Price, this study challenges established ideas about humidity and its potential as an energy source.
Everyone knows that dry air causes static electricity and sometimes causes you to jolt when you touch the handle of a metal door. Water is usually considered a good conductor of electricity, not something that can accumulate charge on a surface. However, it seems that things are different when the relative humidity exceeds a certain threshold.
Researchers, however, have shown that moist air can be a source of charging surfaces at voltages of around 1 Volt.
Towards a new and renewable energy?
There may be a practical application in the future: develop battery water vapor, which can be charged by water vapor in the air. The results can be particularly important.
Water vapor can become a new renewable energy source in developing countries, where many communities still lack access to electricity, but humidity is consistently around 60%.