Scientists have found that it’s possible to generate electric power from Earth’s rotation through its own magnetic field using a magnetic tube resting in a stationary position on the planet’s surface. But before you start dreaming of free, near-limitless energy, the researchers caution that the amount of electricity their experiments generated was far too small to be useful, and it’s not yet clear whether the effect can be scaled up to practical amounts. Still, the results upend decades of research suggesting the phenomenon is impossible.
The concept behind the new research dates back to at least the 19th century, when Faraday was experimenting with electricity. He found that when a conductor moves through a magnetic field, a voltage is induced within the conductor: The magnetic field applies a force on the free electrons inside the conductor, causing them to move.
A 1912 experiment found that if an electromagnet spins on its long axis, its magnetic field does not rotate along with it. And while the Earth spins, its rotational axis doesn’t quite line up with the axis of its magnetic field—which means that any stationary object on Earth spins through a component of the planet’s magnetic field at any given latitude. Put all of this together with Faraday’s earlier findings and you have a potential mechanism through which conductors on Earth’s surface could generate electricity.
However, decades of research suggested that in this scenario, electrons would redistribute themselves within the conductors in a hundredth of a billionth of a second, setting up a static electric field that opposes Earth’s magnetic field. The electric and magnetic forces would rapidly establish an equilibrium, leading to no further net motion of charge following the small initial rearrangement.
“If we can get energy from Earth’s rotation through its magnetic field out in a useful form, that’s obviously amazing, but it’s been thought to be impossible since Faraday’s time,” says Yoshi Miyazaki, a geodynamicist and assistant professor of earth and planetary sciences at Rutgers University–New Brunswick, N.J., who did not take part in the work.
Overcoming Scientific Consensus on Energy
Despite scientific consensus, in 2016, Chris Chyba at Princeton University and Kevin Hand at NASA’s Jet Propulsion Laboratory, in Pasadena, Calif., found that a simple device with a specific shape and set of electrical and magnetic properties might circumvent this limitation.
“We were thinking about ways that outer solar system satellites might be heated by electrical currents as those satellites move through their planet’s magnetic field,” Chyba says. “We started wondering whether there might be an artificial system that could generate electricity by the motion through a background field.”
In a new study, Chyba and Hand, as well as Thomas Chyba, the chief scientist at Spectral Sensor Solutions, in Albuquerque (and Chyba’s brother), built on the 2016 work and created a hollow cylinder about 30 centimeters long and 2 cm wide made of manganese-zinc ferrite. This soft magnetic material is about as electrically conductive as seawater.
The magnetic properties of manganese-zinc ferrite can shield the interior of the cylinder from Earth’s magnetic field. The scientists calculated that as this tube was dragged through the planet’s magnetic field, the resulting electric and magnetic forces would not cancel each other out. An electric current could then flow around certain paths within the cylinder. The scientists detailed their findings on 19 March in the journal Physical Review Research, and presented them at the Global Physics Summit in Anaheim, Calif., on the same day.
The experiments found that when the cylinder’s long axis was oriented north-south, perpendicular to Earth’s direction of spin, it continuously produced about 17 microvolts and 25 nanoamperes of electric current. When it was oriented west-east, parallel to Earth’s direction of spin, no electric current was detected.
The first experiments were accomplished in a dark, windowless underground laboratory with a well-controlled environment. The researchers replicated these effects in a different setting with a largely unregulated environment, a residential building 5.5 kilometers east of their primary lab. They also found that a solid bar of manganese-zinc ferrite did not display these effects, nor did a metal tube with different magnetic and electrical properties display these findings.
“I find it very convincing and remarkable,” says Paul Thomas, an emeritus professor of physics and astronomy at the University of Wisconsin, Eau Claire, who did not take part in this research. “I am very impressed with the very careful experimental methods Chyba and his colleagues have taken to measure and characterize this effect.”
Not everyone in the scientific community is convinced, Miyazaki says. Following the initial 2016 study, a number of papers suggested this effect was impossible, and while the new study addresses these objections, some researchers question whether other factors might explain its findings.
Right now, “the amount of power being generated is extremely low—far too low to be useful,” Chyba says. “Assuming this work is correct, it remains unclear that it is scalable to higher voltages or power. That remains to be demonstrated, and it might not be possible or practical.”
“Hopefully other groups can validate these findings, or not,” Miyazaki says. “If they do get validated, the next question is, ‘Can we scale it?’”
One simple way this device could be scaled up is to reduce the cylinder’s diameter, the researchers note. In doing so, more tubes could be placed together to amplify the generated voltage.
“It is far too early to think about this as a future energy-generation source,” Thomas says. Still, “it’s hard not to be intrigued and excited by the possibilities here.”
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