Naked Science Forum

Life Sciences => The Environment => Topic started by: Petrochemicals on 10/10/2020 22:59:34

Title: How much energy would geothermal generation remove from the crust?
Post by: Petrochemicals on 10/10/2020 22:59:34
If we had geothermal at 2 miles deep, how much energy would be lost from the earth surface? Take Britain as a example, geothermal distributed evenly,  how greater percent is removed from natural conduction and what would the concequences be? Earthquakes like fracking? How much would the surface cool?
Title: Re: How much energy would geothermal generation remove from the crust?
Post by: evan_au on 11/10/2020 03:02:20
Geothermal energy naturally released through the Earth's surface is around 0.06 Watts per square meter (vs around 350 Watts per square meter for incoming solar radiation).
- This is about 30 TerraWatts of thermal energy

Current electricity generation capacity is around 8 TeraWatts of electricity, of which about 5 is from thermal sources.
https://www.statista.com/statistics/267358/world-installed-power-capacity/

If all Earth's thermal electricity came from geothermal sources, it would use about half of the natural total.
- Obviously, geothermal energy is only economically viable in very specific regions with much greater geothermal output than this low average!
- And techniques like drilling and fracking can increase the quantity and quality of geothermal heat above the natural levels in a region.
- However, solar power is distributed fairly evenly over the Earth's surface (over 24 hours), and is economically viable in pretty much all tropical and temperate regions, as long as there are other power sources (or batteries) to provide power overnight...
Title: Re: How much energy would geothermal generation remove from the crust?
Post by: Bored chemist on 11/10/2020 11:32:51
How much energy would geothermal generation remove from the crust?
Practically none.
Where else would we put it?
Where else could it go?
Title: Re: How much energy would geothermal generation remove from the crust?
Post by: Petrochemicals on 11/10/2020 17:13:03
Geothermal energy naturally released through the Earth's surface is around 0.06 Watts per square meter (vs around 350 Watts per square meter for incoming solar radiation).
- This is about 30 TerraWatts of thermal energy

Current electricity generation capacity is around 8 TeraWatts of electricity, of which about 5 is from thermal sources.
https://www.statista.com/statistics/267358/world-installed-power-capacity/

If all Earth's thermal electricity came from geothermal sources, it would use about half of the natural total.
- Obviously, geothermal energy is only economically viable in very specific regions with much greater geothermal output than this low average!
- And techniques like drilling and fracking can increase the quantity and quality of geothermal heat above the natural levels in a region.
- However, solar power is distributed fairly evenly over the Earth's surface (over 24 hours), and is economically viable in pretty much all tropical and temperate regions, as long as there are other power sources (or batteries) to provide power overnight...

Boiling water is lots simpler than solar infrastructure, not to mention far less vulnerable and is on tap as and when needed.
Title: Re: How much energy would geothermal generation remove from the crust?
Post by: Bored chemist on 11/10/2020 18:36:55
My garden + house cover about 130 square metres.
energy naturally released through the Earth's surface is around 0.06 Watts per square meter

So that's 7.8 Watts.
700KJ per day
About 167 Calories per day
If I wanted to heat my house, I would do better to get a cat.

Boiling water is lots simpler than solar infrastructure, not to mention far less vulnerable and is on tap as and when needed.
And, almost everywhere in the world, it just in't available.

To get a decent steam pressure you need rather over 100C- say 150C
And the temperature rises by about 30C per km of depth.
So you need something like a 5km deep hole (or two) to extract power worth about a penny a day.

I'm not offering to buy shares.