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Posted

So ive been thinking this for a while and never really thought of asking anyone that may be in the know such as you guys...

 

Why have we not dug huge holes in the ground and created some perceptual cycle that uses a huge amount of sea water/lava with some turbine in some confined environment? Therein creating a clean, renewable and i'd think extremely efficient (lava being like super mega hot and all) energy source..

 

I guess set up costs may be the biggest consideration but with some sort of unified program and lets just a little IMF funding (they could create a cover for the project more than easily enough though i dont really want to get into the politics of it because it just shows how stupid humanity is), however in relation to science is there any particular reason its not a liable theory?

 

:D

Posted

Why have we not dug huge holes in the ground and created some perceptual cycle that uses a huge amount of sea water/lava with some turbine in some confined environment?

I'm sure you mean "perpetual" cycle, but are you talking about using seawater on lava to create steam to power a turbine for electricity? What are the big holes in the ground for (or are they to get at the lava)?

Posted

I'm sure you mean "perpetual" cycle, but are you talking about using seawater on lava to create steam to power a turbine for electricity? What are the big holes in the ground for (or are they to get at the lava)?

 

just yeh...

 

and the "confined environment" is to trap the water, as for it not to escape back into the atmosphere...

pretty simplistic so im guessing there has to be some serious constraints scientifically, maybe hitting lava is harder than i presume?

 

 

Posted

just yeh...

 

and the "confined environment" is to trap the water, as for it not to escape back into the atmosphere...

 

pretty simplistic so im guessing there has to be some serious constraints scientifically, maybe hitting lava is harder than i presume?

 

 

Does / Would it have any detrimental effects on the environmental effects on the atmosphere?

As Janus mentioned, we have geothermal power already. Your addition of seawater to use as steam to drive a turbine is a problem though. Steam by itself is pretty corrosive to metal machinery, and superheated saltwater is much worse. It's not so much a problem for the atmosphere as it is for equipment.

  • 1 year later...
Posted

Can we chemically modify the water to be less detrimental to equipment? or that what already happens?

 

I only ask because with nuclear power on the rise (a new one being announced here recently) and nuclear waste a clear cut future problem as well as fracking, why are we not investing more resources into technology such as this?

Posted

Can we chemically modify the water to be less detrimental to equipment? or that what already happens?

 

I only ask because with nuclear power on the rise (a new one being announced here recently) and nuclear waste a clear cut future problem as well as fracking, why are we not investing more resources into technology such as this?

 

 

Essentially correct. Typically the water used to produce steam is freshwater. Minimizes corrosion potential and salt buildup. Seawater is used for cooling the steam back down.

 

4873a8ade8f5c016a18cc09174f9498a.png

 

You want to maximize Temperature Hot and minimize Temperature Cold to get as close to maximum efficiency as possible.

 

Can't recall how steam power stacks up in terms of efficiency. I recall looking at it at one point and not being particularly impressed.

 

It is also nominally thermally polluting the ocean when you dump heat there. Lot of ocean available but one could make a case out of it.

Posted (edited)

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

 

Temperature increases ~25 C for each 1 km of depth average on Earth. Which gives 4 km average to reach 100 C. We need 100 C to heat water to become vapor.

 

But it's not constant! Different locations will have different depths at which we will find enough temperature.

 

Drilling 2-3 km well cost ~2 million dollars (at least for gas and oil), hydraulic fracturing is 0.5-1 mln usd.

 

If you are thinking about it seriously you should start from making cheap drilling..

Edited by Sensei
Posted

Can we chemically modify the water to be less detrimental to equipment? or that what already happens?

 

I only ask because with nuclear power on the rise (a new one being announced here recently) and nuclear waste a clear cut future problem as well as fracking, why are we not investing more resources into technology such as this?

 

The locations where lava/magma is easily accessible are limited.

Posted

Can we chemically modify the water to be less detrimental to equipment?

 

We can distill water to get pure H2O without minerals and other unwanted substances.

 

But after pumping to the ground even pure H2O there is chance (close to 100%) that it'll be contaminated inside of Earth.

During travel back to sea level molecules that was flushed by water/vapor will start gathering on installation.

Posted

It's also not perpetual:

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

 

"Even though geothermal power is globally sustainable, extraction must still be monitored to avoid local depletion.[40] Over the course of decades, individual wells draw down local temperatures and water levels until a new equilibrium is reached with natural flows. The three oldest sites, at Larderello, Wairakei, and the Geysers have experienced reduced output because of local depletion. Heat and water, in uncertain proportions, were extracted faster than they were replenished. If production is reduced and water is reinjected, these wells could theoretically recover their full potential."

 

...

 

In Iceland I think, there is some relatively easy natural access to uh... lava I guess that naturally heats water and is used for geothermal energy production. It would surely be possible to have man-made projects that do the same thing, but the effort involved would be monumental. Just to dig all the way through the Earth's crust is a major project... I think it's been planned but not yet succeeded? So to do so and have a major energy plant on top of that is probably not yet economically or perhaps technologically feasible. However, natural sources of geothermal energy are often tapped, I think.

  • 2 months later...
Posted

https://theconversation.com/drilling-surprise-opens-door-to-volcano-powered-electricity-22515

This recent story about accidentally drilling into magma in 2009 and trying to harness the energy demonstrates that your exact idea is feasible at select unusual locations, but also hints at why it's not attempted everywhere. Maybe in the future there will be more experiments at more challenging locations, and some permanent production.

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