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Err...care to explain? I was under the impression that the only engineering issue with deep geothermal was precisely to drill deep enough. Once you've done tha

Err...care to explain? I was under the impression that the only engineering issue with deep geothermal was precisely to drill deep enough. Once you've done that, the rest is pretty straightforward: boil water to run a turbine. Actually I'm 100% sure people are talking about converting coal plants in place with deep geothermal. Also,you put back the water you pump up, so it's literally a closed loop. What environmental issues are you talking about? The mud?

firecall 4y ago
Whatever they are, they are not as bad as what we are currently doing to our atmosphere!
- SoftTalker 4y ago
  Unknown unknowns are what usually get you in the end.
  - pencilguin 4y ago
    More commonly, unknown knowns: "It ain't what you don't know that gets you, it's the things you think you know that just ain't so." Usually credited to Josh Billings. It is, e.g., what turned the Iraq invasion into a national disaster. What was wasted on invading Iraq, to no purpose, could have paid, instead, for the entire transition to wind and solar, decades sooner. Numerous billionaires minted off the fiasco would not now be actively undermining democratic institutions.
- splistud 4y ago
anakaine 4y ago
Former exploration geologist here. Drilling that deep is not easy. Directional drilling equipment is very expensive, and heat + pressure take a toll very quickly on such equipment. Directionality is important as boreholes are rarely straight an it is entirely possible to drill a borehole in a U shape accidentally. Drilling requires high pressure pumps to clear the face of the drill bit, and the cut material must be returned out of hole. That's one hell of a compressor or mud pump. Below a certain depth rock behaviour changes from brittle deformation toward more plastic (and explosive) deformation, to eventually plastic deformation entirely. Groundwater pressures can collapse holes. Deformation can collapse holes. The rock grinds back at drilling gear. Equipment can become stuck and difficult to dislodge. Holes eventually collapse and partially close on their own, requiring casing of the hole. To case, drill a section, retrieve gear from down hole, slide casing in, replace Drilling gear, repeat for each length of casing. It can be quite different per hole, and per rig setup. Some rig setups permit casing in place (this is more a drillers specialist area than my own). Then, there's the issue of keeping the hole open long term. Hydrothermal activity tends to dissolve minerals in water. Minerals tend to crystallise out inside boreholes and pipes over time, like hard water in water pipes in rural areas, constricting flow. What is being proposed is difficult and requires an extreme amount of maintenance through its life cycle.
- getcrunk 4y ago
  To a lay person why do you mean by brittle deformation and plastic sand explosive deformation
  - zdragnar 4y ago
    When something hard is under pressure, it can bend or deform, or it can break or shatter. Imagine a hammer striking a sheet of metal and the metal denting. For a brief moment, the pressure and heat of the hammer strike causes the metal to deform. Conversely, if the hammer hit something like a sheet of glass, it would shatter. Plastic in this sense is not like Tupperware plastic at room temperature, but plastic heated when it is first being molded into shape. Explosive deformation is again like the hammer hitting a sheet of glass- if the glass were already under pressure, breaking it would relieve the pressure causing shards to fly everywhere. Rock at the surface is relatively cold and under little pressure- it is hard, but brittle, and simply breaks. As you get deeper, it is under more pressure and as it breaks, that pressure can get relieved unpredictably (fault lines cause formerly stable walls of already drilled hole to collapse). With even more depth comes more pressure but also more heat, which relaxes the crystalline structure of the rock. It can start deforming rather than breaking. Drill bits become less effective as the rock flows around it rather than getting broken up and pumped away. Edit: if you haven't watched videos of hydrologic presses destroying things on YouTube, you see something like this in reverse; sometimes things can deform a bit, but eventually explode under pressure. The most surprising to be to watch was a deck of playing cards literally shatter.
    - euroderf 4y ago
      Dave Letterman did a whole series of crushing things with a hydraulic press. Quite entertaining.
- jasonwatkinspdx 4y ago
  While all that is true the original article concerns using high intensity microwaves to drill, with an unbalanced purge gas. One of the advantages of this is the potential to create a glass casement as you drill. I'm not in the industry but it's a neat paper and your comment reads like you're simply unfamiliar with what they're proposing, ambitious as it is.
Cupertino95014 4y ago
Maybe a little homework is in order? It's not as though no one's thought of this before, or that no one is putting serious money into it.
twobitshifter 4y ago
It’s usually quakes https://www.theguardian.com/world/2009/dec/15/swiss-geothermal-power-earthquakes-basel https://www.theguardian.com/world/2009/dec/15/swiss-geotherm... https://www.dw.com/en/france-firm-shelves-geothermal-project-after-mini-earthquakes/a-55829869 https://www.dw.com/en/france-firm-shelves-geothermal-project...
cc101 4y ago
I was mostly thinking about the corrosive power of water when it is extremely hot and contains dissolved minerals as this water will. I doubt very much that you could actually reuse the water. Protecting the equipment, disposing the heat, obtaining make up water, and doing something with the brine are major problems. I'm not saying that it can not be done. It probably can, but I feel that the article was a little naive. I suppose that I should say something about injecting high pressure water into the earth. At this depth you are interacting with tectonic forces. High pressure water can unlock existing forces resulting in earthquakes in a manner similar to the quakes triggered by fracking. In summary, there is a cost for everything. There are few, if any, silver bullets capable of solving major problems.
- mwint 4y ago
  > There are few, if any, silver bullets capable of solving major problems I'd argue that there are silver bullets for major problems, but once we find them the problems stop being major. - Sewers were a silver bullet for sanitation - Many medicines have been silver bullets for many diseases - Printing press for information distribution - Telegraph (and later Internet) for fast information distribution - Rail for moving stuff
- jcampbell1 4y ago
  > quakes triggered by fracking Where do you get your misinformation from? This seems to be a widely held false belief.
  - cc101 4y ago
    Where do you get your false information?
    - surfaceofthesun 4y ago
      They’re likely referencing something like this [1]. The “fracking earthquakes” have stemmed lazy disposal of well wastewater. Wells can take millions of gallons of water; ideally we’d be treating reusing that water. —- [1] https://www.usgs.gov/faqs/how-hydraulic-fracturing-related-earthquakes-and-tremors#:~:text=Reports%20of%20hydraulic%20fracturing%20causing,injected%20into%20deep%20wastewater%20wells https://www.usgs.gov/faqs/how-hydraulic-fracturing-related-e....
drtgh 4y ago
https://www.americangeosciences.org/critical-issues/faq/why-geothermal-energy-renewable-resource-can-it-be-depleted https://www.americangeosciences.org/critical-issues/faq/why-... "At any one geothermal field, however, the temperature of the geothermal reservoir or the fluid levels/fluid pressure in the reservoir may decrease over time as fluids are produced and energy is extracted. Produced fluids can be re-injected to maintain pressures, although this may further cool down the reservoir if care is not taken. Over time, it is commonly necessary to drill additional wells in order to maintain energy production as temperatures and/or reservoir fluid pressures decline." { Cooling of the area. New area. New hole } Loop.

firecall 4y ago

Whatever they are, they are not as bad as what we are currently doing to our atmosphere!

SoftTalker 4y ago
Unknown unknowns are what usually get you in the end.
- pencilguin 4y ago
  More commonly, unknown knowns: "It ain't what you don't know that gets you, it's the things you think you know that just ain't so." Usually credited to Josh Billings. It is, e.g., what turned the Iraq invasion into a national disaster. What was wasted on invading Iraq, to no purpose, could have paid, instead, for the entire transition to wind and solar, decades sooner. Numerous billionaires minted off the fiasco would not now be actively undermining democratic institutions.
splistud 4y ago

anakaine 4y ago

Former exploration geologist here. Drilling that deep is not easy. Directional drilling equipment is very expensive, and heat + pressure take a toll very quickly on such equipment. Directionality is important as boreholes are rarely straight an it is entirely possible to drill a borehole in a U shape accidentally. Drilling requires high pressure pumps to clear the face of the drill bit, and the cut material must be returned out of hole. That's one hell of a compressor or mud pump. Below a certain depth rock behaviour changes from brittle deformation toward more plastic (and explosive) deformation, to eventually plastic deformation entirely. Groundwater pressures can collapse holes. Deformation can collapse holes. The rock grinds back at drilling gear. Equipment can become stuck and difficult to dislodge. Holes eventually collapse and partially close on their own, requiring casing of the hole. To case, drill a section, retrieve gear from down hole, slide casing in, replace Drilling gear, repeat for each length of casing. It can be quite different per hole, and per rig setup. Some rig setups permit casing in place (this is more a drillers specialist area than my own). Then, there's the issue of keeping the hole open long term. Hydrothermal activity tends to dissolve minerals in water. Minerals tend to crystallise out inside boreholes and pipes over time, like hard water in water pipes in rural areas, constricting flow. What is being proposed is difficult and requires an extreme amount of maintenance through its life cycle.

getcrunk 4y ago
To a lay person why do you mean by brittle deformation and plastic sand explosive deformation
- zdragnar 4y ago
  When something hard is under pressure, it can bend or deform, or it can break or shatter. Imagine a hammer striking a sheet of metal and the metal denting. For a brief moment, the pressure and heat of the hammer strike causes the metal to deform. Conversely, if the hammer hit something like a sheet of glass, it would shatter. Plastic in this sense is not like Tupperware plastic at room temperature, but plastic heated when it is first being molded into shape. Explosive deformation is again like the hammer hitting a sheet of glass- if the glass were already under pressure, breaking it would relieve the pressure causing shards to fly everywhere. Rock at the surface is relatively cold and under little pressure- it is hard, but brittle, and simply breaks. As you get deeper, it is under more pressure and as it breaks, that pressure can get relieved unpredictably (fault lines cause formerly stable walls of already drilled hole to collapse). With even more depth comes more pressure but also more heat, which relaxes the crystalline structure of the rock. It can start deforming rather than breaking. Drill bits become less effective as the rock flows around it rather than getting broken up and pumped away. Edit: if you haven't watched videos of hydrologic presses destroying things on YouTube, you see something like this in reverse; sometimes things can deform a bit, but eventually explode under pressure. The most surprising to be to watch was a deck of playing cards literally shatter.
  - euroderf 4y ago
    Dave Letterman did a whole series of crushing things with a hydraulic press. Quite entertaining.
jasonwatkinspdx 4y ago
While all that is true the original article concerns using high intensity microwaves to drill, with an unbalanced purge gas. One of the advantages of this is the potential to create a glass casement as you drill. I'm not in the industry but it's a neat paper and your comment reads like you're simply unfamiliar with what they're proposing, ambitious as it is.

Cupertino95014 4y ago

Maybe a little homework is in order? It's not as though no one's thought of this before, or that no one is putting serious money into it.

twobitshifter 4y ago

It’s usually quakes https://www.theguardian.com/world/2009/dec/15/swiss-geothermal-power-earthquakes-basel https://www.theguardian.com/world/2009/dec/15/swiss-geotherm... https://www.dw.com/en/france-firm-shelves-geothermal-project-after-mini-earthquakes/a-55829869 https://www.dw.com/en/france-firm-shelves-geothermal-project...

cc101 4y ago

I was mostly thinking about the corrosive power of water when it is extremely hot and contains dissolved minerals as this water will. I doubt very much that you could actually reuse the water. Protecting the equipment, disposing the heat, obtaining make up water, and doing something with the brine are major problems. I'm not saying that it can not be done. It probably can, but I feel that the article was a little naive. I suppose that I should say something about injecting high pressure water into the earth. At this depth you are interacting with tectonic forces. High pressure water can unlock existing forces resulting in earthquakes in a manner similar to the quakes triggered by fracking. In summary, there is a cost for everything. There are few, if any, silver bullets capable of solving major problems.

mwint 4y ago
> There are few, if any, silver bullets capable of solving major problems I'd argue that there are silver bullets for major problems, but once we find them the problems stop being major. - Sewers were a silver bullet for sanitation - Many medicines have been silver bullets for many diseases - Printing press for information distribution - Telegraph (and later Internet) for fast information distribution - Rail for moving stuff
jcampbell1 4y ago
> quakes triggered by fracking Where do you get your misinformation from? This seems to be a widely held false belief.
- cc101 4y ago
  Where do you get your false information?
  - surfaceofthesun 4y ago
    They’re likely referencing something like this [1]. The “fracking earthquakes” have stemmed lazy disposal of well wastewater. Wells can take millions of gallons of water; ideally we’d be treating reusing that water. —- [1] https://www.usgs.gov/faqs/how-hydraulic-fracturing-related-earthquakes-and-tremors#:~:text=Reports%20of%20hydraulic%20fracturing%20causing,injected%20into%20deep%20wastewater%20wells https://www.usgs.gov/faqs/how-hydraulic-fracturing-related-e....

drtgh 4y ago

https://www.americangeosciences.org/critical-issues/faq/why-geothermal-energy-renewable-resource-can-it-be-depleted https://www.americangeosciences.org/critical-issues/faq/why-... "At any one geothermal field, however, the temperature of the geothermal reservoir or the fluid levels/fluid pressure in the reservoir may decrease over time as fluids are produced and energy is extracted. Produced fluids can be re-injected to maintain pressures, although this may further cool down the reservoir if care is not taken. Over time, it is commonly necessary to drill additional wells in order to maintain energy production as temperatures and/or reservoir fluid pressures decline." { Cooling of the area. New area. New hole } Loop.