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What does drilling a Hole for Water cost here in Europe?

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langwadt:

--- Quote from: Someone on March 23, 2022, 09:08:10 pm ---
--- Quote from: langwadt on March 23, 2022, 01:03:05 pm ---
--- Quote from: Someone on March 23, 2022, 10:22:56 am ---A more on topic wikipedia page has the salient quote that although there is power, its uneconomic/impractical to harvest:

--- Quote from: https://en.wikipedia.org/wiki/Geothermal_power ---most of this power is too diffuse (approximately 0.1 W/m2 on average) to be recoverable
--- End quote ---
Low-grade heat has its purposes, but its not a widely exploitable and magic source of useful energy.

--- End quote ---
here there is an office building that uses an old well with too much nitrate for human consumption for cooling in the summer and via a heatpump heating in winter

--- End quote ---
Which is (almost certainly) using the ground not as an energy source but as a thermal (energy) storage/"infinite" heatsink, that works great in isolated/sparse areas where the climate annually averages around the "comfortable" indoor temperature. When imbalanced it doesnt last forever and isnt as "infinite" as people think:
https://en.wikipedia.org/wiki/London_Underground_cooling
as a utility/storage method it doesnt scale up to mid-desnity suburbs:
https://www.withouthotair.com/cE/page_302.shtml
Are you going to be the one putting energy in for the other users? a massive free-rider problem on that.

--- End quote ---


the ground water is 8-10'C. When used for cooling you could call it a heatsink, when used for heating it is a heat source for the heat pump

Someone:

--- Quote from: nctnico on March 23, 2022, 10:28:03 pm ---
--- Quote from: Someone on March 23, 2022, 10:22:56 am ---
--- Quote from: nctnico on March 23, 2022, 08:54:39 am ---
--- Quote from: Someone on March 23, 2022, 06:14:18 am ---Compared to other sources geothermal is still a tiny tiny speck of US production around 1% of electricity or 0.3% total:
https://www.iea.org/sankey/#?c=United%20States&s=Balance
which is behind the world average of 1.5% of electricity and 0.5% total:
https://www.iea.org/sankey/#?c=World&s=Balance

So yeah, "we" produce a pitiful amount of geothermal energy, and its source/supply is extremely limited compared to alternatives:
https://www.withouthotair.com/c16/page_97.shtml
mW per square meter!

--- End quote ---
Unfortunately that article got the numbers all messed up. https://en.wikipedia.org/wiki/Geothermal_energy says that between 2MW and 10MW can be produced per well.

--- End quote ---
Geothermal energy is not evenly distributed, highly productive wells are the anomalies. Peak power generation is not addressing the energy/lifespan issues of geothermal. A more on topic wikipedia page has the salient quote that although there is power, its uneconomic/impractical to harvest:

--- Quote from: https://en.wikipedia.org/wiki/Geothermal_power ---most of this power is too diffuse (approximately 0.1 W/m2 on average) to be recoverable
--- End quote ---

--- End quote ---
Again, you are not reading carefull enough: 0.1W/m2 is what is being radiated to the earths surface into space. Which is why you need to drill a deep hole in order to get closer to the core to circumvent the insulation of the earth's crust.
--- End quote ---
Sure go deep, its hot down there, but you're depleting the stored energy. Which is why practical geothermal plants move the extraction wells around as they deplete.

Or are you going to try and argue the 100mW/m2 flux at the surface is hiding some other mechanism (the earths core is increasing in temperature over time?). Rather:

--- Quote from: https://en.wikipedia.org/wiki/Geothermal_gradient ---Mean heat flow is 65 mW/m2 over continental crust and 101 mW/m2 over oceanic crust. This is 0.087 watt/square metre on average (0.03 percent of solar power absorbed by Earth)
--- End quote ---

--- Quote from: https://en.wikipedia.org/wiki/Geothermal_gradient ---The heat of Earth is replenished by radioactive decay at a rate of 30 TW. The global geothermal flow rates are more than twice the rate of human energy consumption from all primary sources
--- End quote ---
So what replaces that energy you take out? Or is cooling the core of the earth going to have zero side effects? lolol.

Someone:

--- Quote from: langwadt on March 23, 2022, 11:02:17 pm ---
--- Quote from: Someone on March 23, 2022, 09:08:10 pm ---Are you going to be the one putting energy in for the other users? a massive free-rider problem on that.
--- End quote ---
the ground water is 8-10'C. When used for cooling you could call it a heatsink, when used for heating it is a heat source for the heat pump
--- End quote ---
So its likely with that imbalance of thermal demand that they are drawing down on the thermal store and it will cool down. Why are you all railing against this simple concept? Yes, its hot, but if you use that energy it is replaced very slowly.

NiHaoMike:

--- Quote from: Someone on March 24, 2022, 01:06:14 am ---So its likely with that imbalance of thermal demand that they are drawing down on the thermal store and it will cool down. Why are you all railing against this simple concept? Yes, its hot, but if you use that energy it is replaced very slowly.

--- End quote ---
How long is the time constant? If it's on the order of days or weeks or more, it could make sense to "recharge" it with solar thermal.

Someone:

--- Quote from: NiHaoMike on March 24, 2022, 02:31:24 am ---
--- Quote from: Someone on March 24, 2022, 01:06:14 am ---So its likely with that imbalance of thermal demand that they are drawing down on the thermal store and it will cool down. Why are you all railing against this simple concept? Yes, its hot, but if you use that energy it is replaced very slowly.
--- End quote ---
How long is the time constant? If it's on the order of days or weeks or more, it could make sense to "recharge" it with solar thermal.
--- End quote ---
Its not a simple as a time constant, think a sum of infinite time constants like the model for dielectric absorption (spreading further and further into the volume). Short answer is practical storage lifetimes are months/seasonal, and real sites observe this along with changes in ground temperature on the time scales of years:
"Evaluation of Ground Temperature Changes by the Operation of the Geothermal Heat Pump System and Climate Change in Korea"
https://www.mdpi.com/2073-4441/12/10/2931/htm
Put too many users with imbalanced energy demands in the ground and it will cook or freeze (depending on which direction you push the energy), hence it only being practical if balanced or sparse/selfish/tragedy of the commons/ignoring externalities/short term (the opposite of sustainable).

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