Electrical Device Plugs Directly into Trees for Power

You’ve heard of solar power. How about tree power?

Researchers following upon an MIT study last year that discovered a measurable current inside trees have created a gadget that harnesses that power for electricity.

The University of Washington team sought to further academic research in the field of tree power by building circuits to run off that energy. They successfully ran a custom circuit solely off tree power.

“As far as we know this is the first peer-reviewed paper of someone powering something entirely by sticking electrodes into a tree,” said co-author Babak Parviz, a UW associate professor of electrical engineering.

The Massachusetts Institute of Technology study last year found that plants generate a voltage of up to 200 millivolts when one electrode is placed in a plant and the other in the surrounding soil. Those researchers are working with a company, Voltree, that holds patents for circuits to exploit this new power source.

“It’s not exactly established where these voltages come from. But there seems to be some signaling in trees, similar to what happens in the human body but with slower speed,” Parviz said. “I’m interested in applying our results as a way of investigating what the tree is doing. When you go to the doctor, the first thing that they measure is your pulse. We don’t really have something similar for trees.”

The new UW research, funded in part by the National Science Foundation,  is to be published in an upcoming issue of the Institute of Electrical and Electronics Engineers’ Transactions on Nanotechnology.  Co-author Carlton Himes, a UW undergraduate student, spent last summer hooking nails to trees and connecting a voltmeter. He found that bigleaf maples, common on the UW campus, generate a steady voltage of up to a few hundred millivolts.

Next, a device was developed as a boost converter, to take a low incoming voltage and store it to produce a greater output. Working with input voltages as tiny as 20 millivolts — unlike any existing device — it produces an output of 1.1 volts, enough to run low-power sensors.

“Normal electronics are not going to run on the types of voltages and currents that we get out of a tree,” said co-author Brian Otis, a UW assistant professor of electrical engineering. But as new generations of technology come online, he believes it is valuable to explore the possibilities.

Tree power is unlikely to replace solar power for most applications, Parviz admits. But the system could provide a low-cost option for powering tree sensors that might be used to detect environmental conditions or forest fires. The electronic output could also be used to gauge a tree’s health.

Thanks to Steve G. for submitting the link!

(Source for more info: http://uwnews.org)