3 ms·

Tidal flows are a pretty massive energy reservoir - basically you’ve got all the potential and kinetic energy of the moon’s orbit to draw from. That’s (accordin

Tidal flows are a pretty massive energy reservoir - basically you’ve got all the potential and kinetic energy of the moon’s orbit to draw from. That’s (according to my crude Wolfram Alpha based research) about 3e28J of kinetic energy plus 7e28J of potential energy, for a total of 10^29 Joules. Technically a non renewable resource, but you would be hard pressed to make a dent in that energy budget with any kind of human scale extraction project.

narag 4y ago
Technically a non renewable resource... How's that? Can we consume it? What would be the reaction? Moon altering its orbit?
- andkenneth 4y ago
  Yes this technically degrades the moons orbit. Do it long enough and hard enough and the moon will hit the earth. Shouldn't be of any concern though, because the kinetic energy the moons movement is carrying is insanely high.
  - lazugod 4y ago
    Huh. Would Ice 9 also make the moon crash?
  - stjohnswarts 4y ago
    This doesn't degrade the moon's orbit lol. The energy is there regardless of whether we are using it or not, it will go somewhere, this is just making "useful" work out of it (if anything humans do to the environment, other than going extinct, is really value added for the environment)
hinoki 4y ago
I think it’s the rotational inertia of the earth, not the kinetic energy of the moon. Since the earth is spinning faster than the moon orbits, the tides actually are pulled ahead of the bulge the moon creates, transferring energy from the earth to the moon. Eventually the earth will be tidally locked to the moon (just like the moon is to the earth), and the moon will be in a higher orbit. I guess the turbines will speed this up? As they’ll keep the bulge farther ahead of the moon. EDIT: Wikipedia link https://en.m.wikipedia.org/wiki/Tidal_acceleration https://en.m.wikipedia.org/wiki/Tidal_acceleration
- jameshart 4y ago
  That's true - for some reason I was thinking of tides as following the moon's orbit, when of course they're caused by the earth spinning underneath the moon (tides occcur daily, not monthly. Always check your working against reality, kids). Weirdly, the resulting pool of energy is pretty much the same size - wikipedia quotes the rotational kinetic energy of the Earth as being 2.138E29J. So we're still talking about an insane amount of energy. If you use 17.7TW as the total power consumption of all of humanity, if we were to somehow derive ALL of our energy needs from tidal generation, it would take 358 million years to deplete the rotational energy of the earth.
  - usrusr 4y ago
    Would the turbines make the rotation decay faster, or would they just put some of the energy of rotation decay that happens anyways on a slightly different path towards heat?
deleted 4y ago
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narag 4y ago

Technically a non renewable resource... How's that? Can we consume it? What would be the reaction? Moon altering its orbit?

andkenneth 4y ago
Yes this technically degrades the moons orbit. Do it long enough and hard enough and the moon will hit the earth. Shouldn't be of any concern though, because the kinetic energy the moons movement is carrying is insanely high.
- lazugod 4y ago
  Huh. Would Ice 9 also make the moon crash?
- stjohnswarts 4y ago
  This doesn't degrade the moon's orbit lol. The energy is there regardless of whether we are using it or not, it will go somewhere, this is just making "useful" work out of it (if anything humans do to the environment, other than going extinct, is really value added for the environment)

hinoki 4y ago

I think it’s the rotational inertia of the earth, not the kinetic energy of the moon. Since the earth is spinning faster than the moon orbits, the tides actually are pulled ahead of the bulge the moon creates, transferring energy from the earth to the moon. Eventually the earth will be tidally locked to the moon (just like the moon is to the earth), and the moon will be in a higher orbit. I guess the turbines will speed this up? As they’ll keep the bulge farther ahead of the moon. EDIT: Wikipedia link https://en.m.wikipedia.org/wiki/Tidal_acceleration https://en.m.wikipedia.org/wiki/Tidal_acceleration

jameshart 4y ago
That's true - for some reason I was thinking of tides as following the moon's orbit, when of course they're caused by the earth spinning underneath the moon (tides occcur daily, not monthly. Always check your working against reality, kids). Weirdly, the resulting pool of energy is pretty much the same size - wikipedia quotes the rotational kinetic energy of the Earth as being 2.138E29J. So we're still talking about an insane amount of energy. If you use 17.7TW as the total power consumption of all of humanity, if we were to somehow derive ALL of our energy needs from tidal generation, it would take 358 million years to deplete the rotational energy of the earth.
- usrusr 4y ago
  Would the turbines make the rotation decay faster, or would they just put some of the energy of rotation decay that happens anyways on a slightly different path towards heat?

deleted 4y ago

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