Tracing Energy To Its Roots

If a tree falls in the forest and there's no one around to hear it, who cares if it makes a noise? According to Electronic Design, the big question is whether you can still milk it for power? The answer would be no, but you'd be surprised just what a small New England company has found out about living trees and their potential as a power source.

It all started when Illinois-based inventor Gordon Wadle approached Voltree Power, the small New England company, with a proposal for designing a circuit. Voltree created a circuit without knowing the exact power source until the design was complete. To their amazement, and that of many in the electronics industry, the power source turned out to be a tree.

Big Tree Was Wadle thinking out-of-box or simply out-of-his mind? That was the question that Voltree Power wanted to find out amongst the skepticism of industry peers. Some, like the University of Massachusetts Amherst's Renewable Energy Resource Laboratory's Jim Manwell, went so far as to say he was ‘wildly skeptical’.

The folks at Voltree set out to find out if a tree could actually produce power. They started with some experiments, putting an aluminum rod into the skin of a tree and a copper rod into the soil surrounding the tree. Unlikely as it seemed, the two rods produced a current.

The next step was to find out why and how power was being made. Through some connections, Voltree Power was able to bring their finding to MIT, where a research grant was given to do a complete study of the hypothesis and to truly get to the root cause of how trees produce energy.

At MIT, a bright undergraduate by the name of Christopher Love was given a stipend and the opportunity to find out exactly what was causing trees to produce current. He started in the summer of 2006, eliminating various factors, in an effort to figure out where the consistent 50 to 200 millivolt current between tree and soil was coming from.

Was it a reaction like the galvanic one produced with a potato battery? Or perhaps ionically-charged sap? Then again, perhaps the circuit created by Voltree Power was simply picking up external electromagnetic fields? One by one, all these factors and theories were ruled out.

What was it? Well, as Love would find out, the current was being created by a simple difference in the pH of the soil as compared to that of the skin of tree. The current supplied, when tapped, didn't hurt the living tree at all, which could bode well for future application. Currently, Voltree is working with the National Forest Service and the Bureau of Land Management, providing tree-powered sensor technology to help in the detection of fire danger.
To see a more in-depth article from Xconomy, written by Wade Rouch, click here.