7 ms·

Dumb question and I'm not trying to be pendantic: if the whole world got their power from geothermal, which must (I assume) extract heat and thus cool the core,

by DougN7 9y ago

Dumb question and I'm not trying to be pendantic: if the whole world got their power from geothermal, which must (I assume) extract heat and thus cool the core, at what point is there some effect (on magnetic poles? rotation of earth? tides??)? I wonder similar things about solar - what effect is there on global weather patterns when enough solar energy to make a difference is extracted from the environment? Like, what would happen globally if the entire state of Arizona was in the shadow of solar arrays?

adekok 9y ago
Think of it this way... the Earth is a rock ~4K miles in radius. Essentially all of it is molten rock. When people try hard we can melt rocks to make metals. But we need special-built furnaces, machines, etc. And these furnaces are maybe 50 feet across. So the Earth has a heat stored which is (4K miles / 50 feet)^3 times larger than a blast furnace. i.e. about 7x10^16 times larger. If everyone on Earth had their own personal blast furnace, we'd be controlling 10 million times less energy than what's in the core of the Earth. Similar calculations apply to other calculations. A Physics 101 calculation I did (years ago) was how much a tidal plant would slow down the rotation of the Earth. The answer was by less than a second a day, after 100 years of running. > ke, what would happen globally if the entire state of Arizona was in the shadow of solar arrays? The plants wouldn't grow. :) But seriously, the energy has to go somewhere. If it's hitting solar panels instead of the ground, the net effect to the world is essentially zero. Maybe locally the ground would be cooler because it's in the shade. But that's about it.
- xtreme 9y ago
  Less than a second a day in 100 years is a huge change in earth scale. I'm curious, what kind of tidal plant would even come close? Is it assuming we extract 100% energy from the tidal waves and entirely stop the tides, somehow?
  - simonh 9y ago
    Doesn't it depend on how much less than a second it is?
  - vdnkh 9y ago
    I'm fairly certain stopping the tides would be devastating to the environment since several ecosystems (tidal plains, marshes, riparian zones, etc.) depend upon them.
- infinite8s 9y ago
  You are thinking in linear terms. Humanity's historical energy use definitely doesn't look linear, more like exponential - https://gailtheactuary.files.wordpress.com/2012/03/world-energy-consumption-by-source.png https://gailtheactuary.files.wordpress.com/2012/03/world-ene... I imagine that if we were able to tap into deep geothermal energy the continuing exponential growth would eventually pass some sort of geothermal limit point.
  - foota 9y ago
    This is true, but I know for a fact that US energy use at least has roughly dropped or remained stable for the last decade. Increase in energy use is typically driven by people's increasing incomes and their ability to buy energy for using appliances and such. We can expect energy use to increase significantly globally until everyone is at a base level of income, but after that it should be capped at population growth.
  - mirimir 9y ago
    Remember Asimov's city-planet Trantor. It relied in part on geothermal energy (core taps) with huge radiator arrays at the poles.
- avar 9y ago
  There's no way that a tidal plant running for 100 years is going to change the day by 1 second. You're many orders of magnitudes off. That means that if you built 100 of those plants that in 1 year you'd change the length of the day by 1 second. The 2011 Tōhoku earthquake and tsunami released 3.9×10^22 joules of energy[1] and changed the day by just over a microsecond[2]. A single Tsar Bomba releases 2.1×10^17 joules, so you'd need the energy of around 200 thousand of those to produce the same amount of energy as the earthquake, and then assuming you can direct that energy you need 1000 times more to shift the day by a second instead of a microsecond. That means that each one of your proposed tidal plants would need to generate the energy of 20,000,000 Tsar Bombas per year. That's one Tsar Bomba's worth of energy being released every 1.5 seconds at each one of those 100 plants. Buy stock in sunscreen companies now! Each one of your 100 plants would satisfy all of current yearly world energy production in just 30 minutes[3][4]. I'm too lazy to calculate what that would do to the surrounding area, but I'd wager that they're going to severely depress local property prices due much of the surrounding beach-side property area now being turned into permanent molten lava. The good news is you could probably build really good wind power plants now, due to constant hurricane winds not seen on Earth since the K–T impact, but I digress. I didn't check your molten rock calculation but given how off your tidal plant calculation is I wouldn't be surprised if it's way off as well. 1. https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami#Energy https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an... 2. https://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html https://www.nasa.gov/topics/earth/features/japanquake/earth2... 3. https://en.wikipedia.org/wiki/World_energy_consumption https://en.wikipedia.org/wiki/World_energy_consumption 4. ((5.67x10^20)/(2.1x10^17))/1.5/60 = 30
  - skrause 9y ago
    > and then assuming you can direct that energy you need 1000 times more to shift the day by a second instead of a microsecond. Still off by a factor of 1000, a microsecond is one millionth of a second.
    - avar 9y ago
      Yes you're right. I mixed up micro & milli there. So: * [...] 20,000,000,000 Tsar Bombas per year * One Tsar Bomba going off every 1.5ms * World energy production satisfied in 1.8 seconds We're also going to need more sunscreen.
xtreme 9y ago
The scale at which humans draw energy from the core is negligible compared to the amount. Think about it, earth has been cooling down through radiating from the surface for billions of years. Given the ratio of the geothermal station and the surface area of earth, I don't think there is anything to worry about. As for solar, the incoming energy would have been mostly converted to heat. When we use the electricity produced, we convert it back to heat again. If the entire state of AZ were covered with solar panels, and all the energy spent in NY, there would be some localized changes but not much in the global scale. For the foreseeable future, we are not even close to covering up just 1% of the land area of AZ.
- infinite8s 9y ago
  Earth's radiation scales as a cube of the radius. Our energy usage is growing exponentially. You can apply big-O analysis to this problem ;)
  - badosu 9y ago
    > Our energy usage is growing exponentially. Well, with efficiency gains in the latest years energy consumption (not only electricity) actually is constant or decreasing in developed countries. Add to that decreasing population fertility and if you expect that developing countries are going to follow the same trends after a certain threshold then that's not a good assumption long-term. Japan: https://en.wikipedia.org/wiki/Energy_in_Japan#/media/File:Japan_energy_and_GDP.svg https://en.wikipedia.org/wiki/Energy_in_Japan#/media/File:Ja... US: https://en.wikipedia.org/wiki/Energy_in_the_United_States#/media/File:US_historical_energy_consumption.png https://en.wikipedia.org/wiki/Energy_in_the_United_States#/m... Europe: http://ec.europa.eu/eurostat/statistics-explained/images/thumb/5/52/Gross_inland_energy_consumption%2C_EU-28%2C_1990-2014%2C_ktoe_new.png/800px-Gross_inland_energy_consumption%2C_EU-28%2C_1990-2014%2C_ktoe_new.png http://ec.europa.eu/eurostat/statistics-explained/images/thu...
deleted 9y ago
[deleted]
hutzlibu 9y ago
Like the others said, the earth core is HUGE. But I am a bit sceptical to the no impact scenario. We know a lot allready about the inside of the earth, but afaik we do not really understand it. There are many flows underneath etc. and small changes can have big impacts. Look for example at the amount of artifical CO2 from humans. It is tiny in comparison with the rest of the atmosphere. And yet it gives us a lot of troubles. And about geothermal: well, here in germany there have been allready some minor earthquakes, probably caused by geothermal plants ... (German) http://m.focus.de/wissen/klima/tid-14230/energie-mythen-mythos-geothermie-verursacht-erdbeben_aid_398162.html http://m.focus.de/wissen/klima/tid-14230/energie-mythen-myth...
- aeorgnoieang 9y ago
  I was wondering if anyone else had made the connection to claims (or maybe that's too weak of a word) that fracking causes earthquakes.
  - hutzlibu 9y ago
    Well according to a professor in canada, fracking definitely causes earthquakes ... https://mobile.nytimes.com/2016/11/18/science/fracking-earthquakes-alberta-canada.html https://mobile.nytimes.com/2016/11/18/science/fracking-earth...
  - titanix2 9y ago
    Forage indeed can make earthquakes. An experiment was run in Alsace (France) and as far as I know it was stopped due to this kind of problems. Even if you don't understand French, you can look at pictures of this article: http://www.lefigaro.fr/actualite-france/2013/11/19/01016-20131119ARTFIG00311-alsace-le-village-dont-le-sol-se-souleve.php http://www.lefigaro.fr/actualite-france/2013/11/19/01016-201... Another experiment was stopped in Switzerland for the same reason: https://www.theguardian.com/world/2009/dec/15/swiss-geothermal-power-earthquakes-basel https://www.theguardian.com/world/2009/dec/15/swiss-geotherm...
ChuckMcM 9y ago
Its a fun question on a Friday, with two possible avenues; "How much heat drain would it take to freeze the Earth's core?", and "What would freezing the earth's core do to life on the planet?" For me, the more interesting one, which was the 'bad guy' in the forgettable movie "The Core". The earth's magnetic field is created by the motion of the fluid iron (which is conductive) surrounding the solid core[1]. That it is moving and carries charge creates a dynamic dynamo which determines the strength of the magnetic field. Changes in the fluid are why the magnetic poles move around and sometimes change places. The number 1 feature of the magnetic field (for me at least) is that it deflects the solar wind (those charged particles racing out from the Sun) which would otherwise collide with the gases surrounding our planet and accelerate them outward. Eventually stripping the planet of most of its atmosphere. One of the less well known ways the solar system could wipe out humanity. [1] http://www.physics.org/article-questions.asp?id=64 http://www.physics.org/article-questions.asp?id=64

by DougN7 9y ago

adekok 9y ago

Think of it this way... the Earth is a rock ~4K miles in radius. Essentially all of it is molten rock. When people try hard we can melt rocks to make metals. But we need special-built furnaces, machines, etc. And these furnaces are maybe 50 feet across. So the Earth has a heat stored which is (4K miles / 50 feet)^3 times larger than a blast furnace. i.e. about 7x10^16 times larger. If everyone on Earth had their own personal blast furnace, we'd be controlling 10 million times less energy than what's in the core of the Earth. Similar calculations apply to other calculations. A Physics 101 calculation I did (years ago) was how much a tidal plant would slow down the rotation of the Earth. The answer was by less than a second a day, after 100 years of running. > ke, what would happen globally if the entire state of Arizona was in the shadow of solar arrays? The plants wouldn't grow. :) But seriously, the energy has to go somewhere. If it's hitting solar panels instead of the ground, the net effect to the world is essentially zero. Maybe locally the ground would be cooler because it's in the shade. But that's about it.

xtreme 9y ago
Less than a second a day in 100 years is a huge change in earth scale. I'm curious, what kind of tidal plant would even come close? Is it assuming we extract 100% energy from the tidal waves and entirely stop the tides, somehow?
- simonh 9y ago
  Doesn't it depend on how much less than a second it is?
- vdnkh 9y ago
  I'm fairly certain stopping the tides would be devastating to the environment since several ecosystems (tidal plains, marshes, riparian zones, etc.) depend upon them.
infinite8s 9y ago
You are thinking in linear terms. Humanity's historical energy use definitely doesn't look linear, more like exponential - https://gailtheactuary.files.wordpress.com/2012/03/world-energy-consumption-by-source.png https://gailtheactuary.files.wordpress.com/2012/03/world-ene... I imagine that if we were able to tap into deep geothermal energy the continuing exponential growth would eventually pass some sort of geothermal limit point.
- foota 9y ago
  This is true, but I know for a fact that US energy use at least has roughly dropped or remained stable for the last decade. Increase in energy use is typically driven by people's increasing incomes and their ability to buy energy for using appliances and such. We can expect energy use to increase significantly globally until everyone is at a base level of income, but after that it should be capped at population growth.
- mirimir 9y ago
  Remember Asimov's city-planet Trantor. It relied in part on geothermal energy (core taps) with huge radiator arrays at the poles.
avar 9y ago
There's no way that a tidal plant running for 100 years is going to change the day by 1 second. You're many orders of magnitudes off. That means that if you built 100 of those plants that in 1 year you'd change the length of the day by 1 second. The 2011 Tōhoku earthquake and tsunami released 3.9×10^22 joules of energy[1] and changed the day by just over a microsecond[2]. A single Tsar Bomba releases 2.1×10^17 joules, so you'd need the energy of around 200 thousand of those to produce the same amount of energy as the earthquake, and then assuming you can direct that energy you need 1000 times more to shift the day by a second instead of a microsecond. That means that each one of your proposed tidal plants would need to generate the energy of 20,000,000 Tsar Bombas per year. That's one Tsar Bomba's worth of energy being released every 1.5 seconds at each one of those 100 plants. Buy stock in sunscreen companies now! Each one of your 100 plants would satisfy all of current yearly world energy production in just 30 minutes[3][4]. I'm too lazy to calculate what that would do to the surrounding area, but I'd wager that they're going to severely depress local property prices due much of the surrounding beach-side property area now being turned into permanent molten lava. The good news is you could probably build really good wind power plants now, due to constant hurricane winds not seen on Earth since the K–T impact, but I digress. I didn't check your molten rock calculation but given how off your tidal plant calculation is I wouldn't be surprised if it's way off as well. 1. https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami#Energy https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_an... 2. https://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html https://www.nasa.gov/topics/earth/features/japanquake/earth2... 3. https://en.wikipedia.org/wiki/World_energy_consumption https://en.wikipedia.org/wiki/World_energy_consumption 4. ((5.67x10^20)/(2.1x10^17))/1.5/60 = 30
- skrause 9y ago
  > and then assuming you can direct that energy you need 1000 times more to shift the day by a second instead of a microsecond. Still off by a factor of 1000, a microsecond is one millionth of a second.
  - avar 9y ago
    Yes you're right. I mixed up micro & milli there. So: * [...] 20,000,000,000 Tsar Bombas per year * One Tsar Bomba going off every 1.5ms * World energy production satisfied in 1.8 seconds We're also going to need more sunscreen.

xtreme 9y ago

The scale at which humans draw energy from the core is negligible compared to the amount. Think about it, earth has been cooling down through radiating from the surface for billions of years. Given the ratio of the geothermal station and the surface area of earth, I don't think there is anything to worry about. As for solar, the incoming energy would have been mostly converted to heat. When we use the electricity produced, we convert it back to heat again. If the entire state of AZ were covered with solar panels, and all the energy spent in NY, there would be some localized changes but not much in the global scale. For the foreseeable future, we are not even close to covering up just 1% of the land area of AZ.

infinite8s 9y ago
Earth's radiation scales as a cube of the radius. Our energy usage is growing exponentially. You can apply big-O analysis to this problem ;)
- badosu 9y ago
  > Our energy usage is growing exponentially. Well, with efficiency gains in the latest years energy consumption (not only electricity) actually is constant or decreasing in developed countries. Add to that decreasing population fertility and if you expect that developing countries are going to follow the same trends after a certain threshold then that's not a good assumption long-term. Japan: https://en.wikipedia.org/wiki/Energy_in_Japan#/media/File:Japan_energy_and_GDP.svg https://en.wikipedia.org/wiki/Energy_in_Japan#/media/File:Ja... US: https://en.wikipedia.org/wiki/Energy_in_the_United_States#/media/File:US_historical_energy_consumption.png https://en.wikipedia.org/wiki/Energy_in_the_United_States#/m... Europe: http://ec.europa.eu/eurostat/statistics-explained/images/thumb/5/52/Gross_inland_energy_consumption%2C_EU-28%2C_1990-2014%2C_ktoe_new.png/800px-Gross_inland_energy_consumption%2C_EU-28%2C_1990-2014%2C_ktoe_new.png http://ec.europa.eu/eurostat/statistics-explained/images/thu...

deleted 9y ago

[deleted]

hutzlibu 9y ago

Like the others said, the earth core is HUGE. But I am a bit sceptical to the no impact scenario. We know a lot allready about the inside of the earth, but afaik we do not really understand it. There are many flows underneath etc. and small changes can have big impacts. Look for example at the amount of artifical CO2 from humans. It is tiny in comparison with the rest of the atmosphere. And yet it gives us a lot of troubles. And about geothermal: well, here in germany there have been allready some minor earthquakes, probably caused by geothermal plants ... (German) http://m.focus.de/wissen/klima/tid-14230/energie-mythen-mythos-geothermie-verursacht-erdbeben_aid_398162.html http://m.focus.de/wissen/klima/tid-14230/energie-mythen-myth...

aeorgnoieang 9y ago
I was wondering if anyone else had made the connection to claims (or maybe that's too weak of a word) that fracking causes earthquakes.
- hutzlibu 9y ago
  Well according to a professor in canada, fracking definitely causes earthquakes ... https://mobile.nytimes.com/2016/11/18/science/fracking-earthquakes-alberta-canada.html https://mobile.nytimes.com/2016/11/18/science/fracking-earth...
- titanix2 9y ago
  Forage indeed can make earthquakes. An experiment was run in Alsace (France) and as far as I know it was stopped due to this kind of problems. Even if you don't understand French, you can look at pictures of this article: http://www.lefigaro.fr/actualite-france/2013/11/19/01016-20131119ARTFIG00311-alsace-le-village-dont-le-sol-se-souleve.php http://www.lefigaro.fr/actualite-france/2013/11/19/01016-201... Another experiment was stopped in Switzerland for the same reason: https://www.theguardian.com/world/2009/dec/15/swiss-geothermal-power-earthquakes-basel https://www.theguardian.com/world/2009/dec/15/swiss-geotherm...

ChuckMcM 9y ago

Its a fun question on a Friday, with two possible avenues; "How much heat drain would it take to freeze the Earth's core?", and "What would freezing the earth's core do to life on the planet?" For me, the more interesting one, which was the 'bad guy' in the forgettable movie "The Core". The earth's magnetic field is created by the motion of the fluid iron (which is conductive) surrounding the solid core[1]. That it is moving and carries charge creates a dynamic dynamo which determines the strength of the magnetic field. Changes in the fluid are why the magnetic poles move around and sometimes change places. The number 1 feature of the magnetic field (for me at least) is that it deflects the solar wind (those charged particles racing out from the Sun) which would otherwise collide with the gases surrounding our planet and accelerate them outward. Eventually stripping the planet of most of its atmosphere. One of the less well known ways the solar system could wipe out humanity. [1] http://www.physics.org/article-questions.asp?id=64 http://www.physics.org/article-questions.asp?id=64