Researchers from the University of Soochow, China invent a hybrid solar panel that harvests electricity from friction caused by raindrops, allowing countries in the Northern hemisphere to benefit equally from solar power. A key barrier to the adoption of renewable energy has until now been the intermittent nature of some of these technologies. In particular – solar and wind.
By allowing a hybrid device to generate electricity during the rainy season you eliminate some of the obstacles that countries would otherwise face in getting approved funding for renewable energy. Especially those countries in the northern hemisphere where sunlight is less common.
A key element in this hybrid solar panel is the triboelectric nanogenerator that can produce electricity from the friction of two materials rubbing together. The concept is similar to building up static electricity by rubbing your feet on the ground except in this case the water is rubbing against a compartmentalized layer of graphene that only switches on during rainy weather.
The graphene also produces electricity from free flowing electrons. When the water rushes down the solar panel it splits itself up in to positive and negative ions. Since there are more positive ions then negative ions, mostly in the form of salt based compounds, then the difference in charge potential creates “jumping” electrons that produce more energy.
Since the triboelectric nanogenerator and solar cell share the same transparent electrode, it saves energy that would otherwise be spent on maintaining separate electrodes. Furthermore, the hybrid panel has special grooves that guide the raindrops along, increasing efficiency further.
With that being said – the device is not as good at producing energy from sunlight as mainstream solar panels however, the ability to produce electricity under rainy conditions should end up balancing everything out.
It was able to convert 13% of the incoming light in to electricity, whereas the most common solar panel can convert 15%.. but the extra 6% that comes from rain will be a lot more useful to these northern countries who lack high intensity sunlight. Furthermore, the nano-generator hasn’t even been tested yet, so that could add even more to the equation.