Alternative Energy

Alternative Energy

Alternative energy news, and information about renewable energy technologies.

Jan 06

Energy Harvesting ‘Piezo-tree’ Concept

Posted in Energy Inventions | Future Technology | Wind Power

Piezo-tree Researchers at the Cornell University have taken inspiration from nature and tried to imitate the swaying of tree branches. So what is the difference between natural swaying of trees and energy-harvesting tree created by Cornell University researchers? The flapping leaves developed in the laboratory generate energy which can be utilized by us. They are christened as the “Piezo-tree.” The synthetic leaves of the “Piezo-tree” are connected to a piezoelectric stem. The whole exercise till now appears to be low-cost, and easily scalable.

The movement of leaves is responsible for generating energy. They convert wind energy into electrical energy. The flapping motion of the leaves causes the instability of the aero-elastic system. The main constituent of the “Piezo-tree” is of Polyvinylidene Fluoride (PVDF) which is a flexible piezoelectric material.

The prototype behaves as a tree facing breeze. The Piezo-tree’s flexible plate and film oscillate just as a flag or leaf might flap in the wind. The flapping motion is generated due to instability of the aero-elastic system. Because the flexible piezoelectric material Polyvinylidene Fluoride (PVDF) can endure unpredictable wind strength. They have attached one edge of PVDF element to a cylinder bluff body and left the other edge free. When the breeze blows and touches this bluff body, it leads to a vortex-shedding. Then the periodic pressure difference forces the piezo-leaf to synchronously bend in the downstream of the air wake. The AC signal is gleaned from the flapping piezo-leaf that is working on a periodic bending model, and the electrical energy is then stored in a capacitor after rectifying it with a full-wave bridge.

However, Cornell University researchers were able to generate only about 100 pW because of the weak piezoelectric strain coefficient of PVDF. When the preliminary Piezo-Leaf Generator’s power level was not sufficient enough it was unable to drive even a common LED. Then, researchers attached a piece of plastic film to the end of the leaf along the direction of air flow. This move paid off. Now it showed around 100 times increase of power in the same condition. Researchers also tried various permutations and combinations. They had conducted a series of experiments. They utilized attachments of various shape, area, density and flexibility of plastic and polymer film. This threw out different results in the level of power.

When researchers were trying out different anatomical structure of their synthetic tree their design optimization studies showed that a particular vertical stalk, horizontal leaf arrangement would increase power output by an order of magnitude. This is a enormous, ten-fold progress over current leaf-stalk arrangements. The “piezo-tree” could be utilized as an efficient and exceptional power producer in a variety of environments. For practical and commercial purposes the researchers anticipate to build plant-like devices with hundreds or thousands of piezo-leaves.

  • Charles Tsagli

    Hello dear Researchers,

    As an interested person in fostering the usage of an alternative energy sources such as Wind, Solar and Bio l read your recent research finding on Piezo-tree very interesting and remarkable, congrats. I will like to join these researchers.

    However Wind Power Technology Companies can get in touch with me for Technology Transfer by making business in Africa.

    Thanks for your Info

  • Lynn W.

    So how far are they from making the little fluttering film leaves out of a solar collection material?

  • Mohit Swadia


    I really appreciate your innovative IDEA to produce the energy using the Piezo electric Material as a Leaf… I really interested to know more about your research & your results. I would also ask you… any problems in the Rainy Session or during snowfall?

  • trived

    how much voltage can a single piezo-tree generate? what is the way to protect them durig winter and rainy seasons?

  • earleramage

    Once power generation is acceptable I can see great commercial applications for this technology. E.g as Outdoor decorations and power source, even in the public infrastructure. Imagine pairing street lights with piezo-trees. Now that’s a green idea, lol.

  • BIill Mehess

    What would be the cost of producing 1000s of these leafs relative to the amount of energy they are producing. Also was the 100pw generated per leaf?

    With their 100 fold increase that still works out to only 1 pw per leaf. Am I missing something here?

  • Merijn Rutgers


    Why not attach these to a car, boat or bigger and create extra energy? I mean, just put these on an electric car and you will drive longer distances! And.. if it can be made waterproof, how about lowering it in water so that waves make it move?

    I can think of many more! This is great, my compliments!

  • A Nonymous

    By what the article says, starting with 100 picowatts, then the plastic refinement making it a hundred times more powerful (10000 picowatts), and then a structural refinement adding an “order of magnitude” (100000 picowatts) – you’re left with what equates to 0.001 of a milliwatt per leaf? Doesn’t seem like much? If that is true, you’d need a thousand leaves just to generate one milliwatt! You could get the equivalent of a hundred piezo trees each with a thousand leaves, by instead using a single solar panel… or have I missed something?

  • Boneheaded1

    Just a bunch of engineers tooling around trying to find some backing for an interesting but highly inefficient power generation method. This is too expensive for the output. The cost per kilowatt would be HUGE. Research into renewable/green energy is always welcome, but let’s not dilute the pool of available investment dollars for something like this.

    A real tree is WAY more green and more aesthetic. It cleans the CO2 from the air and the leaves could be placed in a digester to make methane. Sure, over the course of the year a piezo tree MIGHT generate more power than the digested leaves of a real tree but then what about the carbon capture aspect? Not too mention the power/waste cost to build/transport the things in the first place.

    Waste of resource to build these things.

  • trived

    What part is made of piezo material? and which part of the leaf must be made of plastic??

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