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[meto30]

Geothermal power is amazing and nearly limitless. All you do is dig a deep pit, pour water into that pit, and then when the water turns into steam use the steam to run turbines.

Limitless energy anywhere on the planet. It runs day and night, generates no pollution at all, and only requires a source of water to run. You can recycle most of the water as well. Once it runs through the turbine let the steam condense and cool back into water, then pump the water underground again.

I'm still unsure why geothermal is not used more often.

Earthquakes.

When you pump extra water down into the rock like that, you get a lot of quakes. Do that near a major fault, and the worry is that it will trigger a MAJOR eruption, as the water is reducing the friction between the plates, which is what is preventing another quake.

Federal goverment won't even allow companies in the US to do this near major faults or cities or "Other important areas or structures" now.

What is allowed is to drill a few hundred feet down, and run a tube down and back. Cold water pumped through that tube will return very warm in most places of the US. Better than solar heated water.

This is probabilty the reason the Russians dug that deepest hole in the world in Kamchatka, far from human inhabitation... but wait. Kamchatka is on a fault....

[Fanklok]

The obvious solution is to build a pumpstack down to the molten goodness and pump it up to the water to prevent those quakes we can even use the geothermal power provided by doing this to power it.

[Vehudur]

Geothermal power is amazing and nearly limitless. All you do is dig a deep pit, pour water into that pit, and then when the water turns into steam use the steam to run turbines.

Limitless energy anywhere on the planet. It runs day and night, generates no pollution at all, and only requires a source of water to run. You can recycle most of the water as well. Once it runs through the turbine let the steam condense and cool back into water, then pump the water underground again.

I'm still unsure why geothermal is not used more often.

Earthquakes.

When you pump extra water down into the rock like that, you get a lot of quakes. Do that near a major fault, and the worry is that it will trigger a MAJOR eruption, as the water is reducing the friction between the plates, which is what is preventing another quake.

Federal goverment won't even allow companies in the US to do this near major faults or cities or "Other important areas or structures" now.

What is allowed is to drill a few hundred feet down, and run a tube down and back. Cold water pumped through that tube will return very warm in most places of the US. Better than solar heated water.

This is probabilty the reason the Russians dug that deepest hole in the world in Kamchatka, far from human inhabitation... but wait. Kamchatka is on a fault....

This whole "No, you can't, you might cause an earthquake" idea is stupid.  The probability of a large quake is very small, and even if you did, the earthquake would be weaker than if it overcame the stress on its own.

[Bohandas]

The problem with that is that big mineing equiptment actuilly BENDS away from the earth after about 3 or miles down, and the crust is on average 7 miles deep, due to the magnetic feild or something, I'm not 100% on what causes it but I do know that it happens.

I haven't heard of that one.

On a related note, however, I did hear that there were unexpeced temperature anomolies encountered by the Russian Kola Superdeep Borehole project shortly after the project passed the 12.25 kilometer mark in depth.

[Shade-o]

'Mohorovičić discontinuity' is the coolest thing. I learned about it from Total Annihilation, which leads me to believe that anything to do with tapping the mantle is awesome.

[Vehudur]

'Mohorovičić discontinuity' is the coolest thing. I learned about it from Total Annihilation, which leads me to believe that anything to do with tapping the mantle is awesome.

Yes, moho is badass.

Also, things start to get really hot at that point.  To be honest, you'd need something like Adamantine to drill into the mantle, because, well, the pressure and temperature is so high anything we currently have would be destroyed in a few minutes at best.

[BigJake]

'Mohorovičić discontinuity' is the coolest thing. I learned about it from Total Annihilation, which leads me to believe that anything to do with tapping the mantle is awesome.

Yes, moho is badass.

Also, things start to get really hot at that point.  To be honest, you'd need something like Adamantine to drill into the mantle, because, well, the pressure and temperature is so high anything we currently have would be destroyed in a few minutes at best.

It's not the temperature; the mantle is between 500-900 °C.  Steel melts at about 1370 °C depending on the alloy.  It's the pressure that kills you down there.

Speaking of, it sounds like a lot of you seem to be under the impression that the mantle is all molten magma.  Not so.  While the temperature is high enough to melt most of the mantle-rock at sea level, the pressure raises the melting point of the rocks pretty far above that.  The mantle is almost entirely solid.

[Vehudur]

'Mohorovičić discontinuity' is the coolest thing. I learned about it from Total Annihilation, which leads me to believe that anything to do with tapping the mantle is awesome.

Yes, moho is badass.

Also, things start to get really hot at that point.  To be honest, you'd need something like Adamantine to drill into the mantle, because, well, the pressure and temperature is so high anything we currently have would be destroyed in a few minutes at best.

It's not the temperature; the mantle is between 500-900 °C.  Steel melts at about 1370 °C depending on the alloy.  It's the pressure that kills you down there.

Speaking of, it sounds like a lot of you seem to be under the impression that the mantle is all molten magma.  Not so.  While the temperature is high enough to melt most of the mantle-rock at sea level, the pressure raises the melting point of the rocks pretty far above that.  The mantle is almost entirely solid.

It's not a true solid - it's more like a thick paste of sorts.  It won't deform on its own, much, but under pressure it can.  It's not a true liquid until you reach the outer core - and then the inner core is solid (from what we know) because of the sheer pressure.

Sure, steel melts at 1370, but it starts to get soft, deform and weaken long before that, in fact, most drill bits can't drill hotter than 300 or 350.  The ones that can can't handle the pressure.

[BigJake]

Teach me to open my mouth.  I always forget about those damn thin casings they have to use. 

I seem to remember reading about a team a number of years ago that were close to the moho.  They would have made it had their bit not veered 1000ft off course.  I wonder now if they ever made another go.

edit: found em, http://www.iodp.org/

[Vehudur]

Teach me to open my mouth.  I always forget about those damn thin casings they have to use. 

I seem to remember reading about a team a number of years ago that were close to the moho.  They would have made it had their bit not veered 1000ft off course.  I wonder now if they ever made another go.

edit: found em, http://www.iodp.org/

...

When they get it, I'm totally paying whatever I need to pay to have a chunk of (solidified!) moho to use as a paperweight.

[MarcAFK]

This whole "No, you can't, you might cause an earthquake" idea is stupid.  The probability of a large quake is very small, and even if you did, the earthquake would be weaker than if it overcame the stress on its own.

According to wikipedia (i'm too lazy to find the article i origonally read about the plant in switzerland) "The project in Basel, Switzerland was suspended because more than 10,000 seismic events measuring up to 3.4 on the Richter Scale occurred over the first 6 days of water injection."

earthquakes are a very real danger, besides the amount of energy contained in the crust is a small fraction of the amount available in cheaply available sunlight, .... to be honest geothermal is damn cool though.

[BigJake]

To be fair, that energy under our feet has managed to keep the core molten and the mantle plastic for four and a half billion years.  It's not exactly peanuts.

[deoxys413]

'Mohorovičić discontinuity' is the coolest thing. I learned about it from Total Annihilation, which leads me to believe that anything to do with tapping the mantle is awesome.

If this isn't dorfy, I don't know what is. Especially considering the myth concerning clown cars 

[Hyndis]

Lots of tiny earthquakes are much, much safer than the occasional gigantic earthquake. Earthquakes smaller than about 5.0 don't do any damage in first world nations. I would much rather have 10,000 tiny, 2.0-3.0 earthquakes than a single 7.0 quake.

The tiny earthquakes would release the pressure, and prevent the gigantic earthquake.

[BigJake]

But if the geothermal plant is causing the quakes, why the hell would you leave it on?  Doesn't matter how weak you think they are, 3.6s all the damn time, directly caused by the plant, are going to piss A LOT of people off.