Author Topic: What does drilling a Hole for Water cost here in Europe?  (Read 7283 times)

0 Members and 1 Guest are viewing this topic.

Online nctnico

  • Super Contributor
  • ***
  • Posts: 28429
  • Country: nl
    • NCT Developments
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #50 on: March 31, 2022, 01:56:32 am »
This discussion is starting to run in circles  :popcorn:
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Someone

  • Super Contributor
  • ***
  • Posts: 5155
  • Country: au
    • send complaints here
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #51 on: March 31, 2022, 02:59:00 am »
With deep boreholes you trade off area for depth though. It will pull in thermal power from a wide volume and create an expanding plume of lower temperature towards the surface. A single deep borehole is equivalent to a large horizontal pipeline field near the surface.
Which is why its easiest to normalise everything to surface area, mW/m2

Yes, you can use a deep well to pull more power over a larger area and/or volume, but the incoming energy source is well known to be limited per uint of area as its almost entirely coming from below.

This discussion is starting to run in circles  :popcorn:
I just see someone coming back time and time again with outrageous/misleading/bonkers claims who won't even look at the established figures or simple models. If most of the geothermal energy sources were distributed through the crust then it wouldn't have a linear temperature vs depth profile, but almost everywhere does have a close to linear gradient.

Using an electrical equivalent model its a classic transmission line, distributed resistance (thermal conductivity) and capacitance (thermal mass). When you run the numbers on such a model you see a tiny little current source at one end (the thermal energy coming up from deeper within the earth) and a huge amount of capacitance along the way to the surface.

Like a railgun, massive short term power available, but recharging takes a long time.
 

Offline Marco

  • Super Contributor
  • ***
  • Posts: 7043
  • Country: nl
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #52 on: March 31, 2022, 03:38:55 am »
Which is why its easiest to normalise everything to surface area, mW/m2
Which requires quite complex FEM modelling or 160 IQ intuition to actually do. You don't currently have any real model either, just lots of talk and some intuition.
Quote
I just see someone coming back time and time again with outrageous/misleading/bonkers claims who won't even look at the established figures or simple models. If most of the geothermal energy sources were distributed through the crust then it wouldn't have a linear temperature vs depth profile, but almost everywhere does have a close to linear gradient.
It looks linear to the depth we can drill ... which isn't all that deep. With enough assumptions matching measurements with the accepted levels of radiogenic heating isn't a big problem.

It's accepted science that radiogenic heating makes up a large part of the heat flux in the crust, the paper I linked has plenty of references if you want them. This isn't fringe science, it's just a corner of science which escaped your attention before.
Quote
Using an electrical equivalent model its a classic transmission line, distributed resistance (thermal conductivity) and capacitance (thermal mass). When you run the numbers on such a model you see a tiny little current source at one end (the thermal energy coming up from deeper within the earth) and a huge amount of capacitance along the way to the surface.
Talk and intuition.

An excerpts from the above paper :
Quote
Therefore, in stable prov-
inces, the crustal heat production can be calculated by subtracting the
Moho heat flux from the surface heat flux averaged over a sufficiently
wide area (relative to crustal thickness). Results from heat flow studies
yield an average heat production of 0.77 ±0.08 μW m−3 for the Pre-
cambrian crust and 1.08 ± 0.13 μW m−3 for the Phanerozoic with a
range of 0.79–0.95 μW m−3 for the entire continental crust (Jaupart
and Mareschal, 2012).
« Last Edit: March 31, 2022, 03:43:05 am by Marco »
 

Offline Someone

  • Super Contributor
  • ***
  • Posts: 5155
  • Country: au
    • send complaints here
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #53 on: March 31, 2022, 05:01:59 am »
Which is why its easiest to normalise everything to surface area, mW/m2
Which requires quite complex FEM modelling or 160 IQ intuition to actually do. You don't currently have any real model either, just lots of talk and some intuition.
Quote
I just see someone coming back time and time again with outrageous/misleading/bonkers claims who won't even look at the established figures or simple models. If most of the geothermal energy sources were distributed through the crust then it wouldn't have a linear temperature vs depth profile, but almost everywhere does have a close to linear gradient.
It looks linear to the depth we can drill ... which isn't all that deep.
But we're talking about geothermal energy extraction with wells we can drill, which as I said reach depths where approximations to the models are valid. I provided the links to the FEM modelling paper which does all the fancy stuff and still predicts close to a trivial model (one single storage with one input and output).

With enough assumptions matching measurements with the accepted levels of radiogenic heating isn't a big problem.

It's accepted science that radiogenic heating makes up a large part of the heat flux in the crust, the paper I linked has plenty of references if you want them. This isn't fringe science, it's just a corner of science which escaped your attention before.
Even if half the energy comes from the crust (as example: "Controls of Radiogenic Heat and Moho Geometry on the Thermal Setting of the Marche Region (Central Italy): An Analytical 3D Geothermal Model" https://www.mdpi.com/1996-1073/14/20/6511) it doesn't change the fundamental limit of the surface flux. If you pull more than the surface flux out of the area, you are reducing the temperature of the thermal storage. Unless you want to argue that we have an imbalance of thermal flux and the earths core is currently increasing in temperature, then all (100%) of the thermal energy produced (from any depth) is released as the surface flux.

Yes you can have a deep well and suck up heaps of power, but thats flux that doesn't come up where it used to. Hence sticking to mW/m2 as the measure of available sustainable resource. Which the paper you link to here leads with as Fig 1. Its not surprising they can point to locations with high crustal activity and low flux across the Moho discontinuity, such as the South Australian Heat Flow Anomaly. But the sustainable power production is still 100mW/m2 (even in that unusual and "highly active" [for the geological age] region)
« Last Edit: March 31, 2022, 05:03:41 am by Someone »
 

Offline Marco

  • Super Contributor
  • ***
  • Posts: 7043
  • Country: nl
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #54 on: March 31, 2022, 05:33:29 am »
If you pull more than the surface flux out of the area, you are reducing the temperature of the thermal storage.
Pulling less than the available surface area worth of flux in a region is good enough for lesser populated countries.

In my country not so much, but all the large geothermal systems in my country have to operate at yearly net 0 extraction.
Quote
Yes you can have a deep well and suck up heaps of power, but thats flux that doesn't come up where it used to.
So the frost line goes a little deeper.

For the theoretical 20 km deep boreholes, would it really matter if say 2000 km2 of desert soil gets its flux cut in half to run a 100 MW power plant
 

Offline Someone

  • Super Contributor
  • ***
  • Posts: 5155
  • Country: au
    • send complaints here
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #55 on: March 31, 2022, 06:16:37 am »
Yes you can have a deep well and suck up heaps of power, but thats flux that doesn't come up where it used to.
So the frost line goes a little deeper.

For the theoretical 20 km deep boreholes, would it really matter if say 2000 km2 of desert soil gets its flux cut in half to run a 100 MW power plant
Probably wouldn't matter with the slow energy removal and ground cooling being barely noticeable on a human time scale. Even with the 2-3km as modelled above you can pull out 10-20x the surface flux and be out in the thousands of years timeframe for lifetime/side effects.
 

Online nctnico

  • Super Contributor
  • ***
  • Posts: 28429
  • Country: nl
    • NCT Developments
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #56 on: March 31, 2022, 12:56:46 pm »
With deep boreholes you trade off area for depth though. It will pull in thermal power from a wide volume and create an expanding plume of lower temperature towards the surface. A single deep borehole is equivalent to a large horizontal pipeline field near the surface.
Which is why its easiest to normalise everything to surface area, mW/m2

Yes, you can use a deep well to pull more power over a larger area and/or volume, but the incoming energy source is well known to be limited per uint of area as its almost entirely coming from below.

This discussion is starting to run in circles  :popcorn:
I just see someone coming back time and time again with outrageous/misleading/bonkers claims who won't even look at the established figures or simple models. If most of the geothermal energy sources were distributed through the crust then it wouldn't have a linear temperature vs depth profile, but almost everywhere does have a close to linear gradient.

Using an electrical equivalent model its a classic transmission line, distributed resistance (thermal conductivity) and capacitance (thermal mass). When you run the numbers on such a model you see a tiny little current source at one end (the thermal energy coming up from deeper within the earth) and a huge amount of capacitance along the way to the surface.
That doesn't really matter. You have to look at the practical side too. A well won't have an eternal lifetime due to material deterioration. As usual it is a cost versus benefit trade-off. That is what the reports are all about: providing information to assess energy production versus time so people can determine ROI. Having a well that produces for 30 to 50 years is more than long enough. By then technology will have advanced so much that the economics and technologies used are totally different.
« Last Edit: March 31, 2022, 01:01:07 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Someone

  • Super Contributor
  • ***
  • Posts: 5155
  • Country: au
    • send complaints here
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #57 on: March 31, 2022, 09:50:34 pm »
With deep boreholes you trade off area for depth though. It will pull in thermal power from a wide volume and create an expanding plume of lower temperature towards the surface. A single deep borehole is equivalent to a large horizontal pipeline field near the surface.
Which is why its easiest to normalise everything to surface area, mW/m2

Yes, you can use a deep well to pull more power over a larger area and/or volume, but the incoming energy source is well known to be limited per uint of area as its almost entirely coming from below.

This discussion is starting to run in circles  :popcorn:
I just see someone coming back time and time again with outrageous/misleading/bonkers claims who won't even look at the established figures or simple models. If most of the geothermal energy sources were distributed through the crust then it wouldn't have a linear temperature vs depth profile, but almost everywhere does have a close to linear gradient.

Using an electrical equivalent model its a classic transmission line, distributed resistance (thermal conductivity) and capacitance (thermal mass). When you run the numbers on such a model you see a tiny little current source at one end (the thermal energy coming up from deeper within the earth) and a huge amount of capacitance along the way to the surface.
That doesn't really matter. You have to look at the practical side too. A well won't have an eternal lifetime due to material deterioration. As usual it is a cost versus benefit trade-off. That is what the reports are all about: providing information to assess energy production versus time so people can determine ROI. Having a well that produces for 30 to 50 years is more than long enough. By then technology will have advanced so much that the economics and technologies used are totally different.
Redrilling a well into a still productive resource is in no way equivalent to leaving an area denuded of thermal energy and going somewhere else. Current "shallow" geothermal plants are sometimes run in that regime, but being shallow they are leaving those areas to recover over human scale periods (hundreds of years) and:
long term extraction is still limited by the surface flux (where this keeps coming around and around to, fundamental energy in vs energy out).

When talking about deep/large volume extraction its leaving larger and longer lasting legacies. Major cities have histories of hundreds to thousands of years, but thermal energy distribution is more expensive and lossy than electricity (district heating) so it needs to be close to the consumer. Like rubbish dumps, thermal extraction leaves geological problems that need to be worked around. Feel free to pick a lifetime you think is reasonable, but I say anything less than 1000 years is short sighted given how cities tend to stay around longer than that. Intentionally going in with the plan to use all the stored resource in the material lifespan of the well/plant is roughly as sustainable as fossil fuels (completely not sustainable). You can promote selfish solutions all you like, and I'll keep pointing it out for what it is. The IPCC recognise this:
" Energy Systems. In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change"
Note that, in practice, the RE sources as defined here are sometimes extracted at a rate that exceeds the natural rate of replenishment (e. g., some forms of biomass and geothermal energy).

Geothermal energy can be sustainable, but much of it isnt, yet people get all warm and fuzzy about it being zero carbon and "green". There is a geological time scale store of energy that could be exploited for short term gain, just like fossil fuels, the rate of replenishment is very slow (replenishment rate of fossil fuels seems to be hard to find!).
 

Offline CatalinaWOW

  • Super Contributor
  • ***
  • Posts: 5569
  • Country: us
Re: What does drilling a Hole for Water cost here in Europe?
« Reply #58 on: March 31, 2022, 10:17:21 pm »
While I agree philosophically about the concept of overusing a geothermal resource, rough numbers don't seem to make it a likely problem.  The time constants required to make extraction workable seem to make recovery relatively short term.   I haven't been able to come up with solid numbers, but they are definitely knowable.  Deep diamond mines have been extracting heat for decades, not for use at the surface but to make the mines marginally habitable for the miners.  The cost of such extraction should be well known and if there is significant depletion should show a distinct decline over time.  There are other similar sources of hard data.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf