I was wondering if a "mermaid city" (where people lived in the ocean and somehow breathed underwater) could have any means to create or use electricity. Thanks!

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    $\begingroup$ Sure. Waves and currents can be harnessed to generate electricity. $\endgroup$
    – S. McGrew
    Commented Jan 27, 2021 at 22:37
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    $\begingroup$ Would Worldbuilding be a better home for this question? $\endgroup$
    – Qmechanic
    Commented Jan 27, 2021 at 22:42
  • $\begingroup$ Nuclear submarines generate electricity. $\endgroup$ Commented Jan 27, 2021 at 23:16
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    $\begingroup$ Using electricity under water? Not a problem. Discovering electricity? That's a whole different ball of wax. People only discovered electricity by observing the effects of electric charges that were trapped on insulating surfaces by the triboelectric effect. But charges won't be trapped on any surface that is in contact with salt water. $\endgroup$ Commented Jan 28, 2021 at 2:54
  • $\begingroup$ there are submarines using nuclear reactors, no? $\endgroup$
    – anna v
    Commented Jan 28, 2021 at 6:13

1 Answer 1


It is feasible - but would be a lot harder than it was for us.

Conductors - It wouldn't be an easy task for mer-people to smelt copper or other suitable conductors underwater. High temperatures under water are difficult to achieve. A possible solution would be to use metals that can be found in the environment - so maybe gold wiring?

Insulation - A major issue is that the oceans conduct electricity pretty effectively. So all circuit elements would need to be well insulated. Bare wires; open sockets; a 'bread-board' of components sitting on a table; a battery stored on an underwater bench - none of the above would be practical. Possible solutions might be insulating everything, or working in 'vacuum vessels'. In principle it might be possible to replace the sea water in a room with pure distilled water (which has much lower conductivity).

Generation - Something like a lead-acid battery would be feasible (assuming the mer-people can also solve the problems with doing wet chemistry underwater). Hydro-power is obviously impractical, as would be generators powered by fuel-burning motors. Geothermal generation from deep undersea vents might be practical; similarly nuclear power. But any generator would be complicated by the much higher frictional losses when operated in water - so generators and other rotating machinery would be best operated under vacuum.

Reticulation - Probably no specific issue here so long as the insulation problem had been solved. But plug/socket arrangements would need to be clever in order to allow connection/disconnection without producing short circuits in the surrounding water.

Safety - Hideously unsafe unless limited to low voltages.

  • $\begingroup$ Re: fuel-based motors, there are a number substances that burn underwater because they contain their own oxidizers (including some explosives). The most famous example here is thermite, though this may not be suitable for power generation... Re: reticulation, it seems likely that an underwater civilzation would quickly realize the potential of induction for these purposes. You can "plug" an insulated wire with a coil at the end into an insulated socket with another coil inside, and use this for power transfer. $\endgroup$
    – R. Barrett
    Commented Jan 28, 2021 at 23:17
  • $\begingroup$ Inductive energy transfer may be the best option although if there is a significant volume of salt water in the transfer region it could reduce efficiency. $\endgroup$
    – Penguino
    Commented Jan 31, 2021 at 20:17

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