Submitted by tonymmorley t3_yjqjzw in Futurology
vfstevens t1_iupcjjt wrote
Isnt there an argument not to cool down the magma in the core too much? You wouldnt want it to become less fluid
Mantzy81 t1_iupdkat wrote
This would not be a problem. The Earth is plenty hot enough - also, there's really no need to go down that deep. The temperature gradient of the Earth is, on average, about 30°C per Km depth. it doesn't take long to get water hot enough to produce steam to turn a turbine. Some geological bedrock is cooler (i.e. cratons, e.g. Canadian Shield, Russian, South African and Australian cratonic complexes). There are enough radioactive elements in the to keep things toasty for a good while - or at least till the Sun expands and destroys Earth so we should be okay till then.
VRGIMP27 t1_iurd35i wrote
If they have a means of drilling down deep enough it makes me think we should make a lead lined enclosure that deep and just put our nuclear waste in there from our reactors.
Man-made geothermal deep enough down that it's contained and doesn't need active Cooling or storage facilities above ground.
Mantzy81 t1_iuri0hd wrote
Storing nuclear waste below ground already is a thing. But drilling down would be a problem. It's inherently unstable to generate heat. We need to store it somewhere a) stable b) low heat (as we don't want a meltdown) c) where any storage vessel won't melt from environmental heat (so not too deep due to temp gradient or deep but in cold rock d) where it won't interact, if there are issues, that would affect groundwater.
We often use salt mines for this as salt is very good at reducing heat in the source, low permeability and also self heals. It's pretty ideal for storage of nuclear waste. A borehole wouldn't suit for all the reasons that a salt mine does.
Mantzy81 t1_iuufutp wrote
I forgot to mention before, that if you had geothermal everywhere, you wouldn't need nuclear anyway. it's a very clean electricity production method.
boatmcboatface88 t1_iuqiuz9 wrote
From https://phys.org/news/2006-03-probing-earth-core.htmlt: the vast majority of the heat in Earth's interior—up to 90 percent—is fueled by the decaying of radioactive isotopes like Potassium 40, Uranium 238, 235, and Thorium 232 contained within the mantle. These isotopes radiate heat as they shed excess energy and move toward stability. "The amount of heat caused by this radiation is almost the same as the total heat measured emanating from the Earth."
Id say based off this, tapping into the heat to draw power is not going to cause any cooling effect of the earths interior.
Its also cooling albeit very slowly on its own regardless.
AgnosticStopSign t1_iuqfduz wrote
Theyll say its negligible until everyone is tapped in.
The energy will be transferred from the core to electricity, and it will eventually have a noticeable effect on the core. Whether its 100 years or 10000 years, imo, is inconsequential considering the consequences of a no longer spinning, magnetic earth.
But these same people will say “X has 200 years of oil in a reservoir” and never think further, such as: then what? Specifically, what happens to the area the oil had filled, and what will you do when its gone?
taz-nz t1_iuqjetg wrote
The Earth's core radiates somewhere around 47TW into space, which is largely replenished by radioactive decay. You could power the whole planet with nothing but geothermal from now until the Sun shallows the Earth, and you would only cool the core by 1-2%
AgnosticStopSign t1_iuqjong wrote
Ok what are the implications of a 1-2% decrease?
taz-nz t1_iuqmo10 wrote
Basically nothing, the core is 4000-6000 Deg C, iron melts at 1538 Deg C, we are talking lowing it by 40-60 Deg C over 8 Billion years.
UnifiedQuantumField t1_iuqvqtb wrote
> the core is 4000-6000 Deg C
This might be a bit of a side track but here goes anyways...
The currently accepted explanation for this temperature is "decay of radioactive elements within the mantle".
But I suspect that something else is going on. How so?
>The Earth's core radiates somewhere around 47TW into space
Is there really that much radioactive decay going on? Has anyone ever done any calculations to see how much decay of whatever elements would be needed to produce that much energy? Can the process of radioactive decay produce that high a temperature (roughly equal to the surface temp of the Sun)?
taz-nz t1_iur3z4i wrote
Did a little bit more digging, the radioactive decay account for about half the heat being given off 20+TW. The rest is the heat from earth formation and the huge pressures created at the core by earth mass and gravity.
What you have to remember is the earth is really big, and when the earth first formed and was a hot molten ball, most of the heavy elements like iron, uranium and thorium sank deep into the core.
Iron makes up 80% of the inner and outer core, but isn't anywhere near that common on the surface, same goes for Uranium and thorium, while they aren't that common on the surface they are much more so in the core, thus the core has a lot more radioactive decay.
The thermal output of the core was calculated by drilling hundreds of deep boreholes and calculating the heat transfer through the earth crust.
While 47TW may seem like a lot, it's nothing compared to the 173,000TW of energy the sun baths the earth in. (thus the reason why greenhouse gases trapping even a tiny percentage more of the suns energy is very bad)
EnigmaticINTP t1_iupsnpe wrote
Lol, good point.
Rare-Birthday4527 t1_iuptwmi wrote
Gravitational force is free energy. How deep we go is as hot as we get.
Lets say my free energy solutions are born from a inexhaustive set of electromagnetic facts.
Then, we utilize solution number two. The core. The next patent loading.
Nobels succession enroute.
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