Scientists are constantly on the search for sustainable, renewable energy sources, especially as the world strives to be more environmentally friendly. Italian researchers have demonstrated that they can look no further than the trees and plants that are all around us, showing how plants’ leaves can provide enough energy to power LEDs.
An interdisciplinary team of roboticists and biologists at IIT-Istituto Italiano di Tecnologia in Pontedera in Pisa, Italy, have discovered that plants are quite literally a green energy source, generating—by a single leaf—more than 150 volts. This is enough to power 100 LED lightbulbs simultaneously, according to the research team, led by researchers Fabian Meder and Barbara Mazzolai.
The team also showed that a "hybrid tree" made of natural and artificial leaves can act as an electrical generator that converts wind into electricity.
|Researchers in Italy have developed a hybrid plant made of natural and artificial leaves. When wind blows into the plant and moves the leaves, it produces electricity. (Image source: IIT-Instituto Italiano di Tecnologia)|
Mazzolai is a long-time inventor and researcher in the area of bio-inspired technology, particularly at the intersection of robotics and the natural world. In 2012, she coordinated the European Union-funded project Plantoid, developed what researchers called the first plant robot.
In her and Meder’s team’s latest study, researchers focused again on plants, showing that leaves can create electricity when they are touched by a distinct material or by the wind.
Specifically, what they found was that certain leaf structures can convert mechanical forces applied at the leaf surface into electrical energy, Mazzolai said. This is because of the natural, specific composition of most plant leaves, which can gather electric charges on their surface due to a process called contact electrification. These charges are then immediately transmitted into the inner plant tissue that acts similar to a "cable" and transports the generated electricity to other parts of the plant, researchers said.
In their research, then, researchers simply demonstrated that by connecting a "plug" to the plant stem, the electricity generated can be harvested and used to power electronic devices. The IIT team specifically showed that the voltage generated by a single leaf can reach to more than 150 Volts, an amount that can power 100 LED light bulbs each time the leaf is touched.
Plants Convert Wind Into Electricity
To use plants to convert wind into electricity, the team modified a Nerum oleander tree with artificial leaves that touch the plant’s natural leaves. When wind blows into the tree and moves the leaves, the hybrid tree produces electricity, with the amount increasing the more the leaves are touched. Researchers imagine that this effect can be expanded to scale up if applied to the whole surface of a tree’s foliage or even a forest, they said.
The IIT team published a paper on their work in the journal Advanced Functional Materials. They plan to continue the research as a first step for a new EU project Mazzolai plans to coordinate in 2019 called Growbot. The aim of the project is to develop bio-inspired robots—in part powered by the new plant-based energy source--that implement plant-like growing motions.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.
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