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Iceland Eyes Liquid Magma As Energy Source
An anonymous reader writes "Scientists in Iceland have been studying and utilizing the power of geothermal wells for years. In 2009 one such study hit a standstill when a group ran into magma halfway into their dig. The roadblock has become a blessing in disguise, as recent research has shown that the magma can act as a potent new source of geothermal energy powerful enough to heat 25,000 to 30,000 homes."
There are a few supervolcanoes around the world. Yellowstone has been going off about every 3/4 million years for around 20 milllion years, and it's due. Toba nearly wiped out humanity 75000 years ago. Can we do anything about it? Defuse them by sucking all the power out of them with geothermal energy extraction?
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Damn right! If man were meant to fly, he'd have wings!
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As opposed to what? Solid magma is more commonly called "rock".
Iceland already produces energy by pumping water into the ground and on to very hot but still solid magma to produce steam energy. So the distinction matter since the reaction is very volatile if the 'rock' is still liquid.
I imagine that you would have two somewhat vexing problems: One, as you note, temperatures high enough to melt rocks are pretty hard on most machinery. Two, while extremely hot, magma has a distinctly finite amount of energy available. Once you get serious about extracting heat, it will cool and solidify. Once solidified, it will be a mediocre conductor of heat. Thus, unless you want to get only toy amounts of energy out of the system, you will need a fairly large surface area exposed to the magma.
Please, stop cooling magma. No more viscous magna means no more earth magnetic field, hence no more magnetic shield, ie no more life.
Please, don't dig for geothermic energy. Leave alone our earth kernel.
Now let's do some math.
Mass of the earth: 5.9*10^24 kg. Apart from a very thin shell on top, most of that is at a couple of thousand degrees kelvin.
Magma has a much higher specific heat, but let's be conservative and assume all of earth has the same specific heat as iron, or about 460 J/kg
Cooling the earth by a single degree will release about 2.75*10^27 joules
The total world energy consumption from all sources in 2008 was estimated at 4.75*10^20 joules.
At that rate, cooling the interior of the earth by a single degree would power the entire world for 5,789,473 years.
And that's assuming the earth doesn't continue to generate heat from radioactive decay, tidal forces, friction etc.
The human harvesting of geothermal energy is totally insignificant compared to natural cooling over the entire surface of the earth.
Unless they're drilling a hole >3000km deep to tap into the iron-nickel liquid core of the Earth where the Earth's magnetic field is generated, the effect will be irrelevant. And that's leaving aside the fact that it's technically impossible to drill to such depths (the deepest wells barely exceed 10km). Besides, at most you're slightly accelerating the natural process of water circulating in the crust and the normal process of the Earth cooling -- at one teeny-tiny spot compared to, say, the entire mid-oceanic ridge system, which is naturally pumping water through the crust in the vicinity of magma chambers all the time and has been for eons.
Your logic is flawed because you have not considered scale. Total heat flux is estimated at 42TW, and there are ~40GW of geothermal heating and electricity generation. Even if we scaled up geothermal heating by a hundred times or more it wouldn't matter much. All we're doing is drawing the heat out a little faster in small areas, which wouldn't effect the Earth on a broad scale for many millions of years, if there was any effect at all. The Earth is big, and heat flow is remarkably slow within it (rocks are good thermal insulators). It's difficult to perturb heat flow except very locally by artificial means. And generally speaking the areas tapped for geothermal power already have elevated heat flows anyway.
You should worry more about wind turbines affecting weather patterns. At least that might have a plausible basis.
Yes! Instead of lots of inneficient conversion methods, and n orer to overcome the last mile problem, this would finally allow the deployment of Lava To The Home technology, through some simple piping.
Besides heating, hot lava could be used in special taps to allow for inexpensive 3D printing, allowing everyone to produce their own custo made Rock Consumer Appliances.
-><- no
This was an Ancient geothermal plant. The Ancients never met a technology they couldn't make explode, usually taking out at least a sizable chunk of planet.
How profound, we can heat water with magma.
How appropriate, you fight like a... volcano cow?
You are not a brain: http://books.google.com/books?id=2oV61CeDx-YC
You know what they awoke in the darknesss of Eyjafjallajokull.
Björk?
You are not a brain: http://books.google.com/books?id=2oV61CeDx-YC