Controlled Use of Geothermal Energy From Volcanic Lawa

We already are using geothermal energy and probably should be doing more of it.

The problem with messing with active or potentially active volcanoes, is that we don't know when they're going to go off. Even if we did, building the infrastructure necessary to tap the energy would be foolish. It could, and eventually, would, be completely wiped out.

So yes, the energy could be tapped, but never controlled........................not in any meaningful, long term fashion.

Geothermal power is already being used at many places on this planet. The location that prominently comes to my mind is Iceland. Iceland is setting their energy independence goals very high and hope to become completely independent of fossil fuels. Presently only 0.1% of their electricity is produced by fossil fuel. Because of all of the renewable energy available on this cold, volcanic country it will be the pioneering test bed for getting renewable power into all aspects that humanity uses power.

Oh, molten rock is spelled "lava".

Don't forget New Zealand. There's plenty of geothermal going on there.

The U.S. is currently the worldwide leader in geothermal power production....California is by far the leader with a little over 2.5 Gigawatts...still <2% of energy generated...

"The United States currently leads the world's countries in installed geothermal energy capacity with approximately 3,102 MW online and continues to be one of the principal countries to increase the development of its geothermal resources. As of April 2011, geothermal electric power generation is occurring in nine US states: Alaska, California, Hawaii, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming. Other states, such as Colorado, Louisiana, Mississippi, and Texas are soon to be added to the list. "

http://geo-energy.org/plants.aspx

http://en.wikipedia.org/wiki/Electricity_generation

http://en.wikipedia.org/wiki/Geothermal_energy_in_the_United_States

What is the source of earth's thermal energy? Is it residual? If so then how much is there?

What role does it play in earths' magnetic field?

Are there any possible unintended consequences of large scale use?

This is presently open to debate AFAIK. One idea is that the energy is exactly as you said, the residual energy from the Earth's formation and the collision that created the Moon. A competing idea is that the heaviest metals found in the liquid core of the Earth create a fission reactor that is supplementing or maintaining the residual energy of formation. Another idea is the gravity driven pressure generates the thermal energy. At least that's what I remember from a casual conversation with some core dynamics geologists at work. I do remember some other ideas were previously proposed and discredited in our discussion. I hope I remembered the plausible scenarios.

"Earth's geothermal energy originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%).^[1] The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface. "

" Worldwide, about 10,715 megawatts (MW) of geothermal power is online in 24 countries. An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications.^[3]"

^"The Earth's internal thermal energy flows to the surface by conduction at a rate of 44.2 terawatts (TW),^[33] and is replenished by radioactive decay of minerals at a rate of 30 TW.^[34] These power rates are more than double humanity's current energy consumption from all primary sources, but most of this energy flow is not recoverable. In addition to the internal heat flows, the top layer of the surface to a depth of 10 meters (33 ft) is heated by solar energy during the summer, and releases that energy and cools during the winter."

"Geothermal power is considered to be sustainable because any projected heat extraction is small compared to the Earth's heat content. The Earth has an internal heat content of 10³¹ joules(3·10¹⁵ TW·hr).^[3] About 20% of this is residual heat from planetary accretion, and the remainder is attributed to higher radioactive decay rates that existed in the past.^[1] Natural heat flows are not in equilibrium, and the planet is slowly cooling down on geologic timescales. Human extraction taps a minute fraction of the natural outflow, often without accelerating it."

AFAIK no effect on Earth's magnetic field, and no negative consequences, even if at full possible utilization(est at 2TW)...

http://en.wikipedia.org/wiki/Geothermal_energy

As it is very dangerous to touch hot lava it is advisable to spray water on it by helicopter and collect the steam thus generated.

How practicable it is to sray water in such a large scale? How you collect the steam so generated? What you proposed to do with the low pressure steam, if collected?

Let's take a look at Old Faithful. If a structure was built over it such that it was air-tight to the ground, a valve could be devised that would direct the steam either to the atmosphere or to a turbine system. This valve would normally direct the steam to the atmosphere. When an eruption occurs, a control system would close the valve to an optimal position to allow the steam to turn the turbine to create electricity.

This is pretty much a best-case scenario, being that the eruptions are quite predictable. In reality, at other various locations, a lot of capital expenditure would be realized to see significant payoff. Long ROI, and fraught with maintenance issues IMHO.

Thanks Redfred for spell correction of 'lava'. GA's to SolarEagle, Redfred & Mikerho for their valuable comments. Still many issues raised in my original post is not yet commented. I reproduce a part of OP for further comments:

"At present we lack technology for its controlled use. The most fearsome thing is prediction of disasters. If we get technology to track variation in pressure and temperature of of liquefied lava deep inside the earth and its depth from solid top surface, we may get some courage to take further risk."

The point is, if we are able to measure (by advancement of technology) rate of increase of pressure of lava deep inside the earth, its spread and volume, average temperature and minimum depth from top surface then can't we risk for controlled use? It's like a gasket leak in pressure cooker which will not allow its safety valve to open (see OP).

This would be very dangerous and impractical, and no government would allow it, even if you could find somebody foolish enough to attempt it...which is doubtful....Volcanos are dangerous and unpredictable, they spew poisonous gas without warning, the ground around them is unstable and changes without warning at times....Even if the ground was stable enough and the volcano didn't erupt for a long enough period of time to build some geothermal facility, eventually the structure would fail, or catch fire, or be blown from the face of the Earth, endangering all those present, and no company would insure such a facility, ever...

http://en.wikipedia.org/wiki/Volcano

Cross-section through a stratovolcano (vertical scale is exaggerated):

1. Large magma chamber
2. Bedrock
3. Conduit (pipe)
4. Base
5. Sill
6. Dike
7. Layers of ash emitted by the volcano
8. Flank

9. Layers of lava emitted by the volcano
10. Throat
11. Parasitic cone
12. Lava flow
13. Vent
14. Crater
15. Ash cloud

GA for detailed photo.

Before a volcano erupts drill a deep hole and pumpwater into it and collect the steam generated. By this method you can capture the thermal energy(heat)in the volcano before it erupts thereby cooling and preventing it from erupting at the same time generate electric power by steam turbine.

All you will do is increase the thickness of the cap on the volcano. Causing it to have a increase of internal pressure before it blows. Which you can't control because they are unpredictable. You can't determine the amount of energy needed to be drawn out to control it. Or build facilities to do so as fast as it can change. So what you get when it does erupt is more devastation.

Close but you cannot qualify that it will be more devastation. The energy level and the location of a volcanic eruption can neither be predicted or anticipated with today's technology. So one cannot say that doing or not doing anything will lead to more or less devastation.

As for the idea that one will increase the cap on a volcano by drawing geothermal energy out of a location is just pure hubris. The average thickness of continental crust is about 30 kilometers. The crust is much thinner at an active volcano site but the idea that a few centimeters of added crust hardening and a few decades of building construction will make any significant difference to the structural integrity of the crust is absurd.

"As for the idea that one will increase the cap on a volcano by drawing geothermal energy out of a location is just pure hubris."

So by this statement you feel that we do not have the technology to draw enough thermal energy out to make any effect?

We certainly are capable of making some local effect changes that can be demonstrated and measured. However, the magnitude of geologic forces and energies dwarf our efforts. In this article from Science Daily they inadvertently drilled into a magma flow at 2.1 kilometers of depth. I believe that it is reasonable to assume that this bore hole was less than a meter in diameter. In the article there's a picture of the drilling facility next to the crater Viti. The crater is at least ten times wider than the height of what looks like a two story building in the picture. That pictured eruption crater rivals the diameter of the crater produced by the Castle Bravo detonation of a 15 megaton nuclear device (63*10^15 joules) but came from under ground to blow out the mass instead of pushing most of the mass away as Castle Bravo did. These forces and energies dwarf our efforts.

Oh, for those who wish to claim the "butterfly" effect that a hole drilling can make an erruption more likely... This drilling reached magma last year and no new volcano was formed. Also a major part of the "butterfly" effect theory is that one cannot discern which butterfly flapped, where or when this flap happened, when or where a hurricane will happen. One cannot discern at all the given hurricane producing butterfly from a butterfly that didn't produce a hurricane, nor can one discern a hurricane produced by a butterfly from one not produced by a butterfly. The given condition is a fallacy.

GA Redfred for the article. Your comment is not going aside from the subject. A quote from the article:

"The Iceland Deep Drilling Project has not abandoned the search for supercritical geothermal resources. The project plans to drill a second deep hole in southwest Iceland in 2013."

My original thread was just an emagination to attract a discussion among CR4 members. In fact, besides safety hazard, solid waste generation will be of alarming volume in that model. After reading the above article I started thinking on another model which will totally eliminate solid waste generation. In this we need to drill two holes of suitable diameter (depending on MW of power to be produced) to reach up to magma. In one hole boiler feed water is be pumped at very high pressure (say 300 bar) and from other hole high pressure steam shall come out after heat exchange with super hot magma. Technological advancement may be needed to prevent possibility of chocking the pipes my magma and complicated control mechanisms.

As extracting heat from magma may tend to reduce its temperature on a small scale, it may bring down the pressure also which may result in reduction in possibility of eruption.

As a younger man spent a few years on a drilling rig. Not sure how your reference to them drilling in to a lava flow correlates to what the poster proposes to do. It's a relatively shallow well. Drilled many that deep in 11 days. Most likely did no testing which the flow would have showed up on.

I understand what a futile attempt it would be to try to control a volcano. Also the forces that can be released. Mount St. Helens comes to mind reported at 20 megatons.

If the resources were put in place to try to do so. Which would be considerable. What effect do you think it would have?

as i've got it the eruption is due water-liquid-gas content of magma not the metal-mineral content of

checking my PDF-s DB for "whats in the area(depth) of interest" ...

• Mineralogical Magazine, April 2000, Vol. 64(2), pp. 157-184
  Pressure-induced transformations
  in deep mantle and core minerals
  R. J. HEMLEY*, H. K. MAO AND S. A. GRAMSCH
  Geophysical Laboratory and Center for High-Pressure Research, Carnegie Institution of Washington,
  5251 Broad Branch Road N.W., Washington D.C. 20015, USA
  // ^_ it's the "water in depths"
• 10.1098/rsta.2002.1081
  Zoned mantle convection
  By Francis Albar μe de1 a nd Rob D. van de r Hilst2
  1Ecole Normale Sup¶erieure de Lyon, 69007 Lyon, France
  2Massachusetts Institute of Technology, Cambridge, MA 02139, USA
  Published online 27 September 2002
  // might bear "where to build" relevance
  // the gulf of california E to N quarter inland behind should be your area of interest ((muhahaa))
• Earth and Planetary Science Letters 254 (2007) 90-105
  Tomographic evidence for the mantle upwelling beneath
  southwestern Japan and its implications for arc magmatism
  Junichi Nakajima ⁎, Akira Hasegawa
  Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science,
  Tohoku University, Sendai 980-8578, Japan
  Received 12 June 2006; received in revised form 16 November 2006; accepted 16 November 2006
  Available online 4 January 2007
  R.D. van der Hilst
• doi: 10.2306/scienceasia1513-1874.2005.31.283
  // -- just in asence of GPR alternates !!! GPR-s are not too ?? common !!! = we don't have variety of "do it all" GPR-s
• 
  

...fraught with maintenance issues...

From my experience, this statement is DEAD on. As just one example at one geothermal plant my former employer owned... The ground is active enough that the incoming road is destroyed about twice a year thus forcing the employer to helicopter in employees at each shift (for about 7-14 days at a time while the repairs are made).