A new study finds that water vapour in the atmosphere may serve as a potential renewable energy source in the future.
The search for renewable energy sources such as wind, solar, hydroelectric dams, geothermal, and biomass, has preoccupied scientists and policymakers alike, due to their enormous potential in the fight against climate change.
The research is based on the discovery that electricity materializes in the interaction between water molecules and metal surfaces. They sought to capitalize on a naturally occurring phenomenon: electricity from water.
Electricity in thunderstorms is generated only by water in its different phases -- water vapour, water droplets, and ice. Twenty minutes of cloud development is how we get from water droplets to huge electric discharges like lightning.
The researchers set out to try to produce a tiny low-voltage battery that utilizes only humidity in the air, building on the findings of earlier discoveries.
A much more recent study showed that certain metals spontaneously build up an electrical charge when exposed to humidity.
The scientists conducted a laboratory experiment to determine the voltage between two different metals exposed to high relative humidity, while one is grounded.
They found that there was no voltage between them when the air was dry. But once the relative humidity rose above 60%, a voltage began to develop between the two isolated metal surfaces.
When they lowered the humidity level to below 60%, the voltage disappeared. When they carried out the experiment outside in natural conditions, they saw the same results.
This study challenges established ideas about humidity and its potential as an energy source. Water is normally thought of as a good conductor of electricity, not something that can build up-charge on a surface. However, it seems that things are different once the relative humidity exceeds a certain threshold.
The results may be particularly important as a renewable source of energy in developing countries, where many communities still do not have access to electricity, but the humidity is constantly about 60%.