A Princeton-led team has built a tabletop device that generates voltage directly from Earth’s rotation through its magnetic field. While the power output is orders of magnitude too small for practical electronics, the breakthrough suggests Earth’s spin could someday provide constant, fuel-free energy if the effect scales up. The team is now calling for independent labs to reproduce the results.



I didn’t bother to read the paper, but the article says the system produced “10s of nanoamps at 10s of microvolts”. I’ll just assume each of those values are “100”, since that’s the highest value you could describe as “10s” of something.
That works out to 0.01 nanowatts. For comparison the tiny solar panel on a solar powered calculator might produce 0.0075 watts, or 750 million times that amount of power.
In reality, since wattage is a multiple of volts and amps, lowering both of those figures from my highball estimate would massively decrease the wattage. The solar calculator probably produces billions of times more power than this 1 foot long cylinder.
So, i think its neat that they were able to measure an effect, but the article really should not even be mentioning power generation.
This.
That thing is at best a sensor, certainly not a power generation device.
The antenna in my phone likely “harvests” orders of magnitude more electricity when receiving signal.