Researchers Use Magnetic Induction to Generate Energy — From the Earth's Own Magnetic Field
Rather than move a magnet over a wire, the team allowed the Earth's spin to do it for them — and generated measurable energy.
Researchers from Princeton University and the Jet Propulsion Laboratory (JPL) at the California Institute of Technology, working with Spectral Sensor Solutions, say they've figured out how to harvest energy from the Earth's rotation through its own magnetic field — and, despite the date, it's not an April Fools joke.
"It seems crazy," first author Christopher Chyba admits of his work with his brother Thomas Chyba and JPL's Kevin Hand, in an interview with Physics Magazine's Michael Schirber unveiling the project. "It has a whiff of a perpetual motion machine."
That project in detail: a device that generates energy just by sitting there, using a variant of the commonly-understood phenomenon by which passing a magnetic field over a wire induces a voltage in said wire. Except there are no moving parts in the team's machine: the magnetic field in question is the Earth's own, and the "wire" is a hollow manganese-zinc ferrite tube aligned perpendicular to the Earth's spin.
"Controlling for thermoelectric and other potentially confounding effects (including 60 Hz and RF background)," the team explain of their experiments, which were carried out in absolute darkness to ensure nothing was harvesting energy from stray photons, "we show that this small demonstration system generates a continuous DC voltage and current of the (low) predicted magnitude."
How low? 25 nanoamperes at 17 microvolts. In other words, not enough to be useful — but enough to cast doubt on the belief that such a process would be impossible, with the electric field always cancelling out the magnetic force to result in a net-zero gain. It also represents something of a nose-thumbing from Chyba and colleagues, who published a paper suggesting the possibility of such energy generation in 2016 only to see a number of papers arguing the counterpoint published in response, to their critics.
The team's work has been published under open-access terms in the journal Physical Review Research; Schirber's Physics Magazine interview is available on the APS website, while more information is available in IEEE Spectrum's coverage of the paper.