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Today I discovered that geothermal energy is a thing, cool! An immediate question that comes to mind is how much "energy potential" does the earth store and "ho

Today I discovered that geothermal energy is a thing, cool! An immediate question that comes to mind is how much "energy potential" does the earth store and "how is it generated"? I'd imagine something about gravity or magnetic waves that move the iron* core and stuff. Anyone know some resources I can read more about this?

giggyhack 1y ago
Assuming we can drill deep enough and harness it, the thermal energy in the earth's crust is essentially infinite.
- b112 1y ago
  People said "the Earth is too big, human activity can't change the climate". Now look at where we are. I wonder, if we draw enough heat out... would the core cool enough to shrink? And if so, would the crust collapse to the new size? Pure speculation of course, but did the first guy burning coal know the outcome? Anyhow, I love geothermal, think you're right, but just got tweaked on the word "infinite".
  - rkomorn 1y ago
    Isn't the atmosphere we're affecting on the order of 1 millionth of Earth's mass? It'd take multiple orders of magnitude more impact from humanity for us to actually affect the core, no?
  - thehappypm 1y ago
    Just some rough physics.. Q = m c ΔT m = mass of the crust (roughly 10^22 kg) C = specific heat of crust (roughly 1000 J/kg·K) ΔT = 1 K Q = 10^25 joules would be needed to lower the earths crust by 1 degree K About 10,000 years worth of today’s human energy consumption
    - conditionnumber 1y ago
      I wonder how much ΔT you need at the crust to meaningfully change Earth's magnetic field by altering convection patterns in the outer core. I don't know enough physics to attempt an answer.
      - aDyslecticCrow 1y ago
        Calculating or simulating how earths magnetic field behaves or is generated is quite a complex task. So im doubtful we can usefully estimate it to such precision. It would be interesting though.
        hollerith 1y ago
        We know that if the convection in the outer core stops, the Earth's magnetic field stops, and removing enough heat from the core will stop the convection.
        aDyslecticCrow 1y ago
        Yes but calculating the energy draw required for any measurable change in this effect is very different from knowing the rough process it operates on. We know how weather works quite well, but knowing if it will rain in a week is an entirely different beast.
        hollerith 1y ago
        I've seen a confident estimate in the form of a calculation. They know what kind of compounds (term?) are in the outer core and they know the minimum temperature those compounds need to be at to be free-flowing enough to sustain the field. And I'm pretty sure we know the current temperature of the outer core. My memory is that the calculation found that if humanity switched to geothermal for all its energy needs, then in only about 1000 years, the core cools enough for the magnetic field to stop, but I am not sure. (We should definitely deploy geothermal in the Yellowstone caldera though long enough to cool it down enough so that it will not erupt again.)
  - deleted 1y ago
    [deleted]
  - stevage 1y ago
    There is also the issue that using geothermal energy can cause earthquakes.
    - aDyslecticCrow 1y ago
      I think thats actually disputed. I'm not entirely sure though and i dont have the time to look it up right now.
    - 0xDEAFBEAD 1y ago
      Here are some links I found related to this Pro-geothermal position: https://www.caltech.edu/about/news/producing-clean-energy-can-diminish-earthquake-risk https://www.caltech.edu/about/news/producing-clean-energy-ca... Anti-geothermal position: https://news.stanford.edu/stories/2019/05/lessons-south-korea-solving-geothermals-earthquake-problem https://news.stanford.edu/stories/2019/05/lessons-south-kore... My conclusion: Geothermal makes research into plate tectonics and earthquake mitigation considerably more valuable, so we can figure out how to do it in a way that reduces earthquakes rather than creating them.
aDyslecticCrow 1y ago
Alot of the heat comes from radioactive decay. Heavy radioactive elements under alot of pressure and heat. There's also friction from our moon (earth seems to have a more active core than many other planets) and simply being very well isolated. (Rock is a terrible heat conductor) Also... Iceland. They're massive in aluminium production for a reason. They have basically infinate abundant energy boiling out from the ground. Here in sweden its used by alot of homes for heating; getting a well producing 60c water is pretty cheap. (A single home may have their own well) The issue is using it for power really only becomes viable when you reach superheated steam temperatures. And at those depths; drills melt, so its use outside of volcanic regions has been real slow.
- 0xDEAFBEAD 1y ago
  >earth seems to have a more active core than many other planets Fun fact: Plate tectonics has been proposed as an explanation for why complex life is here and not elsewhere.

giggyhack 1y ago

Assuming we can drill deep enough and harness it, the thermal energy in the earth's crust is essentially infinite.

b112 1y ago
People said "the Earth is too big, human activity can't change the climate". Now look at where we are. I wonder, if we draw enough heat out... would the core cool enough to shrink? And if so, would the crust collapse to the new size? Pure speculation of course, but did the first guy burning coal know the outcome? Anyhow, I love geothermal, think you're right, but just got tweaked on the word "infinite".
- rkomorn 1y ago
  Isn't the atmosphere we're affecting on the order of 1 millionth of Earth's mass? It'd take multiple orders of magnitude more impact from humanity for us to actually affect the core, no?
- thehappypm 1y ago
  Just some rough physics.. Q = m c ΔT m = mass of the crust (roughly 10^22 kg) C = specific heat of crust (roughly 1000 J/kg·K) ΔT = 1 K Q = 10^25 joules would be needed to lower the earths crust by 1 degree K About 10,000 years worth of today’s human energy consumption
  - conditionnumber 1y ago
    I wonder how much ΔT you need at the crust to meaningfully change Earth's magnetic field by altering convection patterns in the outer core. I don't know enough physics to attempt an answer.
    - aDyslecticCrow 1y ago
      Calculating or simulating how earths magnetic field behaves or is generated is quite a complex task. So im doubtful we can usefully estimate it to such precision. It would be interesting though.
      - hollerith 1y ago
        We know that if the convection in the outer core stops, the Earth's magnetic field stops, and removing enough heat from the core will stop the convection.
        aDyslecticCrow 1y ago
        Yes but calculating the energy draw required for any measurable change in this effect is very different from knowing the rough process it operates on. We know how weather works quite well, but knowing if it will rain in a week is an entirely different beast.
        hollerith 1y ago
        I've seen a confident estimate in the form of a calculation. They know what kind of compounds (term?) are in the outer core and they know the minimum temperature those compounds need to be at to be free-flowing enough to sustain the field. And I'm pretty sure we know the current temperature of the outer core. My memory is that the calculation found that if humanity switched to geothermal for all its energy needs, then in only about 1000 years, the core cools enough for the magnetic field to stop, but I am not sure. (We should definitely deploy geothermal in the Yellowstone caldera though long enough to cool it down enough so that it will not erupt again.)
- deleted 1y ago
  [deleted]
- stevage 1y ago
  There is also the issue that using geothermal energy can cause earthquakes.
  - aDyslecticCrow 1y ago
    I think thats actually disputed. I'm not entirely sure though and i dont have the time to look it up right now.
  - 0xDEAFBEAD 1y ago
    Here are some links I found related to this Pro-geothermal position: https://www.caltech.edu/about/news/producing-clean-energy-can-diminish-earthquake-risk https://www.caltech.edu/about/news/producing-clean-energy-ca... Anti-geothermal position: https://news.stanford.edu/stories/2019/05/lessons-south-korea-solving-geothermals-earthquake-problem https://news.stanford.edu/stories/2019/05/lessons-south-kore... My conclusion: Geothermal makes research into plate tectonics and earthquake mitigation considerably more valuable, so we can figure out how to do it in a way that reduces earthquakes rather than creating them.

aDyslecticCrow 1y ago

Alot of the heat comes from radioactive decay. Heavy radioactive elements under alot of pressure and heat. There's also friction from our moon (earth seems to have a more active core than many other planets) and simply being very well isolated. (Rock is a terrible heat conductor) Also... Iceland. They're massive in aluminium production for a reason. They have basically infinate abundant energy boiling out from the ground. Here in sweden its used by alot of homes for heating; getting a well producing 60c water is pretty cheap. (A single home may have their own well) The issue is using it for power really only becomes viable when you reach superheated steam temperatures. And at those depths; drills melt, so its use outside of volcanic regions has been real slow.

0xDEAFBEAD 1y ago
>earth seems to have a more active core than many other planets Fun fact: Plate tectonics has been proposed as an explanation for why complex life is here and not elsewhere.