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You can have geothermal power everywhere if you drill deep enough

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Re: You can have geothermal power everywhere if you drill deep enough

#291

Post by ZeroGravitas »

p1mrx wrote: post #236
ZeroGravitas wrote: post #54

This sounds like cool tech, and the re-use of the existing generation assets is clever, but just running costs of the steam part of an existing plant struggles to compete on a financial basis with wind turbines and solar PV so it'll probably only ever be a niche thing. Shared ground loops connected to heat pumps are a more boring tech with more potential to have a global scale impact.

Assuming that people commit to buying 24/7 carbon-free energy at any price, on-demand generation like geothermal will be quite valuable during the times when wind and solar are underperforming. So geothermal will mainly compete with nuclear and storage, not wind and solar.

Yep, and like nuclear, it has a high up front cost that needs to be amortized over near constant use to be viable which means it prices itself out of that role pretty quickly compared with say green ammonia fired peaker plants that mostly incur costs when actually used and also use the green energy being produced in large quantities.

Re: You can have geothermal power everywhere if you drill deep enough

#292

Post by oliveshell »

hectormalot wrote: post #273
oliveshell wrote: post #140

Earlier quoted context omitted.

That’s what they mean. My neighbor had one drilled and the contractors showed up with a huge well-drilling truck. It’s just a huge vertical drill with segments you add on as it goes deeper, like an oil well drill.

Correct, it's big but I wouldn't say huge (maybe 4.5x2.5m). This is the machine they used: https://conrad-stanen.nl/nl/producten/boxer-200

Most drills I’ve used fit in your hand. Compared to that, it’s huge :)

(although on rereading I didn’t mean to say ‘huge’ twice in my previous post)

Re: You can have geothermal power everywhere if you drill deep enough

#293

Post by smolder »

genewitch wrote: post #289
goda90 wrote: post #270

Earlier quoted context omitted.

And crop nutrient depletion

plants are 99.9999% carbon from carbon dioxide, though... what? edit: i mean of the things in a plant that contain carbon and don't, 99... whatever percent of a plant is atmospheric carbon. all the soil amendments added are to replace stuff like fungus that normally forms a relationship with nearby plants and gives nutrients that plants use to modulate energy production and transpiration (or whatever), similar to how…

Studies show higher atmospheric carbon means the crops grow faster and have lower micronutrient density than crops grown in lower co2 environments. Our crops grow faster but aren't as healthy for us.

Re: You can have geothermal power everywhere if you drill deep enough

#294

Post by smolder »

ComradePhil wrote: post #290
ravi-delia wrote: post #211

Earlier quoted context omitted.

Except, you know, 100% of the energy obtained by fossil fuels also eventually becomes waste heat. All of our electricity consumption and production is a rounding error to the earth. Global warming only works because the Sun can do most of the work.

>Except, you know, 100% of the energy obtained by fossil fuels also eventually becomes waste heat. And? Where did I say it doesn't? >All of our electricity consumption and production is a rounding error to the earth. Agree. But I'm talking to those who believe solar is the solution to global warming... when what solar does is capture more energy from the sun and turn it to heat.

That's still such an inconsequential effect compared to the additional heat trapping caused by atmospheric ghg increases from fossil fuel burning that it doesn't really tip the scales. Solar does solve the biggest problem: ghg emissions. In order of importance: #1: stopping emission of greenhouse gasses on a huge, planet destroying scale, ~#15 reducing current ghg concentrations back to baseline, ~#900 worrying about reflectivity or absorption levels of solar energy installations.

Re: You can have geothermal power everywhere if you drill deep enough

#295

Post by smolder »

jstimpfle wrote: post #133
ComradePhil wrote: post #27

Earlier quoted context omitted.

Solar is also trapping more energy than what would never be there. If the sun's rays just hit the ground, a portion of it would be reflected back. We're using dark material to aborb most of what would be reflected back and we end up trapping more energy than we should... Solar panels are around 15% efficient, which means 85% of this trapped energy is immediately converted to heat, heating the local environment... and…

Is that a problem though? What percentage of earth surface would be covered by solar panels if the world went 100% solar?

No, it's not, the parent poster overestimates the effect. Something like 0.1% of the surface would need panels. Energy trapped by those solar panels pales compared to what's trapped by all the greenhouse gasses we've emitted burning coal and oil.

Re: You can have geothermal power everywhere if you drill deep enough

#296

Post by thescriptkiddie »

charles_f wrote: post #216

Somewhat related, I used to think that residential geothermal heating was basically harvesting the steaming heat from the soil to your house. I figured that would require seating on a volcano. In fact it's using a heat pump, and liquid circulating in pipes burried a few feet underground to act as a thermal sink, to either heat or cool down a house. This works well because the temperature in the ground doesn't fluctua…

A ground-source heat pump is technically not geothermal, because the bulk of the heat comes not from the earth but from the sun. You are basically using the soil as an enormous thermal battery which charges up in the summer and stays warm (relative to the air) through the winter. Real geothermal power plants are actually indirectly harvesting heat from the molten inner layers of the earth, which is mostly leftover from the the formation of the planet.

Re: You can have geothermal power everywhere if you drill deep enough

#297

Post by kragen »

iancmceachern wrote: post #250
aaronblohowiak wrote: post #219

Earlier quoted context omitted.

In a fire, A wooden ladder remains viable king after an aluminum one! Soft happens WAY before melt

Thermal mass and thermal conductivity also play a role in this example. Two more reasons a wooden ladder is better in this scenario. For ladders at the same temperature, the aluminum one would conduct more thermal energy, quicker, into a user's hand then a Wooden one. Making a wooden one more usable for longer in this scenario even though the aluminum one would technically last longer. This is why wooden sauna seats…

Wood has about the same specific heat as aluminum, but a wooden ladder weighs much more, so a wooden ladder at the same temperature contains much more sensible heat to eventually conduct into the user's hand.

Re: You can have geothermal power everywhere if you drill deep enough

#298

Post by kragen »

kragen wrote: post #98
anonporridge wrote: post #9

Something I've always wondered. Wouldn't massive scale geothermal end up pumping more heat into the atmosphere that otherwise wouldn't be there? In contrast, the energy collected by solar and wind generators is from the energy added to Earth by the sun and would be energy in our atmosphere regardless of whether or not we collect it. But it seems like the heat inside the Earth's core should be fairly well insulated by…

It could. The available fossil sensible heat energy is something like hundreds of millions of years of sunlight. Right now geothermal is uneconomic except in special situations, and human world marketed energy consumption is four orders of magnitude smaller than insolation, so it’s not yet a practical concern.

It turns out to be millions of years of sunlight, not hundreds of millions.

    You have: earthmass 2000 K 1J/g/K
    You want: J
        * 1.1944337e+31
        / 8.3721685e-32
    You have: earthmass 2000 K 1J/g/K/(circlearea (earthradius) 1000 W/m2)
    You want: years
        * 2968252.9
        / 3.3689851e-07

Re: You can have geothermal power everywhere if you drill deep enough

#299

Post by abrazensunset »

theptip wrote: post #225

The idea of drilling deep geothermal to repurpose existing fossil plants is an elegant one. I imagine others have thought of this before, but it was new to me. Being able to take over the existing equipment (turbines, power transmission connections) seems appealing. Of course, it all depends on how expensive the drilling process is vs. the existing capital asset in the turbines, but maybe you could hit a price point…

It's worth noting that hydraulic fracturing itself is rarely the problem. Issues come from moving fluid volumes somewhere else during production: subsidence due to extraction from the place where the hydrocarbons are, or (most often) from injecting produced water into disposal wells, eventually triggering faults. Some of that produced water was introduced by the operations, but most of it was just in the ground with the oil & gas being produced.

It's possible to directly trigger small faults with while fracturing the rock, or to do something stupid like fracture into a freshwater zone other people are using, but that's not what's driving quakes in e.g. Oklahoma.

Re: You can have geothermal power everywhere if you drill deep enough

#300

Post by eru »

napier wrote: post #267
eru wrote: post #139

Earlier quoted context omitted.

If you can concentrate energy, eg into a neutron beam, then it's not waste heat. It's a form of energy you still can get useful energy out of. The only thing you can do with true waste heat on the scale of earth is to radiate it into space. You might want to look into eg https://en.wikipedia.org/wiki/Second_law_of_thermodynamics

My comment was written with precisely the second law of thermodynamics in mind. If you’re generating energy at a rate greater than you have a use for, to the point that you have a problem, yet also able to harvest it, then you want to radiate it back into space, yes. Neutron beams would be a cool, perhaps fanciful yet potentially practical way of doing that in a concentrated manner.

Either I completely misunderstand you, or you don't understand thermodynamics at all.

Do you know how the Carnot cycle works, and more importantly, why no process to generate electricity from heat can be more efficient?

> If you’re generating energy at a rate greater than you have a use for,

Huh? Why would anyone do this? Just turn off the excess capacity.

(Do keep in mind that when we produce electricity, we necessarily have waste heat. That waste heat has energy, but it's not energy we can use.)

Any kind of heat engine essentially works like a water wheel: you take heat from a high temperature source (water from a source at big height), you send it through your apparatus, and out comes heat at a lower temperature (water at a lower height) on one side, and some electricity on the other.

> ... then you want to radiate it back into space, yes. Neutron beams would be a cool, perhaps fanciful yet potentially practical way of doing that in a concentrated manner.

Huh? If you can concentrate the waste energy, it's not waste heat. You'd want to use it instead of just bleeding it into space. Do you understand that?

You'd use that concentrated form to run another engine.

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