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Ask HN: Practicality of harnessing geomagnetic fields for electrical generation?
Years ago I would have asked this on the 'Overflows. Alas, those innocent days are long gone. I could always ask AI, but how can you know?
The Earth produces a moving magnetic field (small teslas, but large extent yes?). Moving magnetic fields produce electrical current, right? Could you add "geomagnetic power" to other clean/renewable sources with the right technical solution, or is it fundamentally impossible?
- sloaken 11mo agoThis seems like a very obvious solution. But of course I am ignorant on electricity generation and or the physics involved. I am hopeful someone will enlighten us.
- gcheong 11mo agoIt's apparently been done, but the amount generated was very small and it's not clear it could be scaled up to any useful amounts. https://spectrum.ieee.org/earths-magnetic-field https://spectrum.ieee.org/earths-magnetic-field
- keepamovin 11mo agoExcellent! I like it when experimentalists and technologists prove some significant set of theoreticians wrong!
- sloaken 11mo agoInteresting read, thank you for finding it.
- keepamovin 11mo agoReally hoping for some better, first-principles or technically comprehensive answers here from the HN hive-mega-mind....sigh. And I wasn't the only one... I reckon nobody gives out expertise for free these days, myself included, so I understand y’all’s reluctance. Double heavy sigh.
- mikewarot 11mo agoThe trivial amount of power you can generate is great for nerd sniping[1] , but won't even light a flashlight. I wouldn't expect a lot of discussion about it. [1] https://xkcd.com/356/ https://xkcd.com/356/
- keepamovin 11mo agoHmm, I'm not sure that's true. The 30cm Zn-something tube generates mcirovolts (1e-6), but you can imagine longer, and more, such tubes. With volume (width x depth x height) you can quickly scale up to 1000s of volts or more. THat's just 1 experiment!
- mikewarot 11mo agoOn the other hand, there is thermal heat radiating up from the ground, and during daytime, up to a full kilowatt per square meter of solar illumination. Both of which dwarf this effect. We've been nerd sniped ;-)
- keepamovin 11mo agoI guarantee my goal was not to nerd snipe HN. It's just such a huge amount of power, a giant spinning iron core, a planet sized magnetic field. Hmmm, I still feel there's a way to get more power than we expect out of that geomagnetic technically instead of the micro power from that Zn tube, imagine something like an AA battery's worth, but the size of a red-bull can. Anyway, my next idea is what about tapping the Earth-Sun coupling. This is not "solar PV" territory, but rather the energy that the sun dumps into the Earth that is channeled through the field and produces effects like auroras, particle cascades. The crazy thing is, this is an enormous amount of energy: - 10–100 GW quiet, up to 1–10 TW (or more) in big storms. It's global, but concentrated by field lines into ring-shaped auroral ovals over the poles. Would be cool if there was a way to tap it. It doesn't need daylight, unlike solar. It's constant, and 10-100x more in solar storms. Crazy power. Would be very cool to tap.