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It definitely wouldn't be practical compared to other sources of energy, but given currently plausible technology, would it be theoretically possible to use the movement of tectonic plates (as in continental drift, not earthquakes) to generate electricity? If it is, how would it be done? If it isn't, why not?

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    $\begingroup$ A 3 beer question or 4? $\endgroup$
    – Solar Mike
    Aug 5, 2022 at 18:25
  • $\begingroup$ Consider what you would need for the force interface between plates and your energy collecting device. How do you ensure the force does not get to the point where you start to induce cracks in your plates, allowing most of these masses to carry on their merry way without contributing to your collector? I suspect an appropriate comparison would be collecting water from a river with needles... $\endgroup$
    – Abel
    Aug 13, 2022 at 2:09

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If not lending ourselves to overly unrealistic scenarios, then no. In theory however, then yes.


According to National Geographic, "The North American and Eurasian tectonic plates, for example, are separated by the Mid-Atlantic Ridge. The two continents are moving away from each other at the rate of about 2.5 centimeters (1 inch) per year." For comparison, an oak tree grows about 1-3 feet per year (reference).

Using simplified hand calculations (link gives elaboration on why and how the rough estimate was given), one may approximate the kinetic energy of the Eurasian plate as 1500 Joules, which is a similar value to someone riding a bike.

Scientific American states about harvesting of energy from earthquakes that "Just how to harness tectonic energy is the big question. One way would involve stringing quartz crystals, which can transfer electricity via piezoelectricity, underground along known fault lines.

When tectonic plates shift, the crystals could transfer the energy they pick up to a grid-connected storage medium for later use. But this is hardly practical, for one because earthquakes rarely happen in a predictable manner let alone in the exact spots where energy harvesters would have set up their gear. Also, fault lines tend to run deep below the Earth’s surface, so laying down a network of quartz crystals would involve mining out shafts and connecting them underground on a scale way beyond what humans have done to the present."

(I am aware you specified movement not from earthquakes, but since we're talking theoretically, then one could image the same technique but in a way larger scale).


The point is, although the continental plates might seem useful since they're large and moving, they are in fact too large and moving too slowly to be useful when compared to other energy sources.

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Technically yes, but it would be practically impossible. In xkcd What-if? #47 Randall Munroe states that the "drag force on the North American plate is on the order of $10^{19}\ newtons$." Thus the forces driving continental drift must be of the same order of magnitude. A very rough calculation can calculate that at $1\ cm/year$ and $10^{19}\ newtons$ the power we are dealing with is: $$0.01\ \frac{m}{year}*\frac{1\ year}{365\ days}*\frac{1\ day}{24\ hours}*\frac{1\ hour}{60\ minutes}*\frac{1\ minute}{60\ seconds}\approx3.17*10^{-10}\ m/s\\3.17*10^{-10}\ m/s*10^{19}\ N=3.17\ GW$$ That's a lot of power but for reference the Hoover Dam can generate $2.08\ GW$, so nothing revolutionary.

Then there's the practicality, to harness that energy we would essentially need to attach a rope to a continent (strong enough to resist a force of $10^{19}\ newtons$ or about a trillion Saturn V rockets) and run that rope to a spool connected to a generator (that is fixed to some other continent or somthing). Also the rope is moving a less than $1\ nm/s$ so we'll probably need a transmission with a gear ratio of about 1,000,000,000:1. So, as you said, the practicality is not there.

All in all, if as a civilization you can make this setup and have it work, then you probably have other ways of collecting energy, like massive space based solar arrays or large scale fusion reactors, maybe even a Dyson swarm.

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The rate of continental drift is very small.

The currently accepted rate for the separation of the Americas from Europe and Africa is about 2.5 cm/year

At such low rates of movement, no useful energy could be generated economically.

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    $\begingroup$ Surprised the airlines don’t use the change in distance to increase prices even more :) $\endgroup$
    – Solar Mike
    Aug 5, 2022 at 18:52
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    $\begingroup$ @SolarMike: It's a zero sum game situation. They'd have to give deductions for routes that fly over subduction zones. :) $\endgroup$
    – Fred
    Aug 5, 2022 at 18:57

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