When we turn on a kettle, we expect to see water vapor. When we have a hot shower, water vapor fogs up the windows. There are many cases throughout our day where we encounter water vapor and don't even realize it. No one ever looked at it as a possible energy source. That was up until now. A recent study shows that scientists may have found a way to produce renewable energy from water vapor.
The world is on a hunt for renewable resources. Though coal was once a good idea, our environment is being choked by outdated energy sources. Policymakers and scientists have dedicated years to renewable energy sources, including wind, geothermal, biomass, solar, and hydroelectric dams. But by focusing their attention on these energy sources, they ignored an important once. Though their intentions were good, a study by Tel Aviv University found that water vapor in the atmosphere can actually be used as a renewable energy source in the future.
The research was led by Prof. Colin Price in collaboration with Prof. Hadas Saaroni and doctoral student Judi Lax. Their research is based on the discovery that electricity materializes in the interaction between water molecules and metal surfaces.
As Prof. Price explains, "We sought to capitalize on a naturally occurring phenomenon: electricity from water. Electricity in thunderstorms is generated only by water in its different phases -- water vapor, water droplets, and ice. Twenty minutes of cloud development is how we get from water droplets to huge electric discharges -- lightning -- some half a mile in length."
Their research was simple. Their goal was to produce a small low-voltage battery using only humidity in the air. It sounds like a walk in the park, right? Not so easy. They did this experiment based on the findings of the 19th-century English physicist Michael Faraday, who discovered water droplets, due to the friction between the two, can charge metal surfaces. And their findings were remarkable. "We found that there was no voltage between them when the air was dry," Prof. Price explains. "But once the relative humidity rose above 60%, a voltage began to develop between the two isolated metal surfaces. When we lowered the humidity level to below 60%, the voltage disappeared. When we carried out the experiment outside in natural conditions, we saw the same results."
Prof. Price continued, "Water is a very special molecule. During molecular collisions, it can transfer an electrical charge from one molecule to the other. Through friction, it can build up a kind of static electricity. We tried to reproduce electricity in the lab and found that different isolated metal surfaces will build up different amounts of charge from water vapor in the atmosphere, but only if the air relative humidity is above 60%. This occurs nearly every day in the summer in Israel and every day in most tropical countries."
What this study really does is challenge our preconceived notions about humidity and that it could potentially be used as a resource. "People know that dry air results in static electricity and you sometimes get 'shocks' you when you touch a metal door handle. 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," Prof Price explains.
So what does this mean? Will we be using water vapor as an energy source? Well, not right now. This is just in the initial experimental phases and will certainly take some time before any machinery is designed. But this does show the world that we're capable of undergoing a complete switch to renewable energy, the only thing is we need to do it. As Prof Price says, "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%." It sounds like water vapor has the ability to change millions of lives.