Can energy be produced from the rustling of leaves and branches? Yes, say researchers from Ohio, who have already generated piezoelectric energy.
A research team from the US state of Ohio have developed a technology that makes it possible to tranform random vibration frequencies into usable energy by exploiting the natural movements of tree-like structures.
According to a study in the Journal of Sound and Vibration, forests are able to produce energy thanks to their natural movements and the charges these produce - not as much as a wind farm, but nevertheless enough to power certain sensors and control systems.
It's based on a principle called piezoelectricity, where electrical charges are built up through the vibrations of certain solid materials, which can then be converted into energy. However, these vibrations differ from material to material and are incredibly difficult to capture. And when it comes to forests of course, it also depends on the strength of the wind that has to make the material - in this case leaves and branches - move in the first place.
Grafik: Harne et al
This is how it works: the wind causes the leaves and branches to vibrate naturally. These vibrations are picked up and their frequency exploited in such a way that genuinely usable energy is produced. The developers have tested their technology it on an artificial mini-forest made of small L-shaped steel beams that they wrapped in polyvinyliden flouride (PVDF) a piezoelectrical material. The test run produced approximately 2 volts of energy.
Everything is surrounded by natural vibrations of course, so piezoelectricity can actually be produced from any kind of material - even, for example, from the action of typing on a typewriter. In fact, that technology has already been patented.
Could piezoelectricity be THE energy source of the future? It's too early to tell. But this study and the latest developments in the field of piezoelectricity go to show that it's certainly an interesting possible source of clean energy and one that we could be hearing a lot more about in the future.