11/11/2009 05:12 am ET Updated Dec 06, 2017

Scientists Draw Electricity from Trees

Guest Post From Dan Shapley From The Daily Green

University of Washington scientists have discovered a new source of electricity: Trees.

In an experiment that will seem familiar to students of the potato, the scientists stuck one electrode into a bigleaf maple, and another in the ground, and saw that the tree generated a tiny stream of electricity -- a few hundred millivolts. That's not enough electricity to do much ... but run a circuit and get published in the scientific journal Institute of Electrical and Electronics Engineers' Transactions on Nanotechnology.

(As of that potato, this experiment is different, the authors said: "The tree-power phenomenon is different from the popular potato or lemon experiment, in which two different metals react with the food to create an electric potential difference that causes a current to flow." The tree experiment uses the same metal for both electrodes.)

Photo: University of Washington

A few hundred millivolts of electricity isn't enough to do much. Or is it? The scientists built a custom boost converter using nanotechnology that stores input voltages of as little as 20 millivolts (20 thousandths of a volt) and produces 1.1 volts -- enough to run low-power sensors that might monitor environmental conditions, help detect forest fires or gauge the health of trees.

And in the future, who knows? Maybe we will be plugging in our iPods on long hikes with a little tree power. "As new generations of technology come online," co-author Babak Parviz said, "I think it's warranted to look back at what's doable or what's not doable in terms of a power source."

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