Hydrothermal Energy is Now a Reality

I been following your idea in other threads, and it's good that you have opened your own. I like your idea, but even as you have admitted, there are daunting obstacles to overcome. All, however, I believe can be worked out.

A question that I posted in another thread, that I believe is more appropriate here:

Hey, bc, I have a question for you, about your project. I'm not a geologist, and I really don't know. I understand, from my limited knowledge and research, that the hydrothermal vent water is very hot, and under tremendous pressure. I've also learned that it is highly mineralized. As this water is brought up to ambient temps. and pressures, will these minerals fall out of solution? Could this pose a problem for the machinery?

And, do any of these minerals have an economic value? So, as not only producing a source of energy, you could be mining at the same time?

Just a thought.

Thanks for bringing your question here. I think it is far more appropriate here.

Oh lordy, do they have value! If you do a net search on hydrothermal veins, you'll find that they're essentially hydrothermal vents of the geologic past. They are the places where the best surface mines are located.

I'll copy and paste some text from my site.

Although the temperatures are extremely hot (400° C or 750° F), the high (225 bar or 3,200 psi) ambient pressure keeps the fluid from boiling, and the liquid fluid's contact with 2° C or colder surrounding seawater causes a fantastic, uninterrupted and uninterruptible cocktail of metals and minerals to precipitate out of the fluid and rain down upon the seabed below. The precipitate includes iron, gold, silver, copper, zinc, cadmium, manganese, and sulfur, along with significant amounts of methane gas mixed into the fluid. Halides, sulphates, chromates, molybdates and tungstates are also abundant. These are among the richest ores found anywhere on Earth.

That's why this is the first practical deep-ocean mining system as well. You're simply gathering up what nature is freely offering, and I like that concept.

The expected transit time from vent to surface is only 12 minutes, so with decent insulation the temperature loss, and therefore the likelihood of the minerals falling out of solution is almost negligible in my view, but it is one of the things that must be determined through computer modeling and the like.

I have never imagined the hydrothermal fluid being used directly on a steam turbine because of the solid content. The blades are far too delicate for that, and it will have to go through a heat exchanger first. However, the alternate embodiment of the system is a closed loop design in which the hydrothermal fluid is not brought to the surface at all. Instead, the energy is used to heat a clean working fluid within an insulated closed loop for direct use against the turbine. I can also use turbine-less generating technology such as solid state thermovoltaics that avoid the Carnot cycle completely.

There's one more advantage to this technology. If the fluid is brought to the surface and allowed to flash to steam, that steam will distill back into fresh water. While there might be additional processing steps involved, the vast majority of the desalination energy is provided by nature itself, and the sites can produce millions of liters of fresh water a day.

Right. I haven't looked thru all the previous posts (so the question may already have been answered). The concept looks interesting (if not slightly familiar to those that have been working with geothermal, magma thermal or any other use-heat-to-convert-water-to-steam generation principle (yes nuclear is one of them too)).

My questions were regarding the amount of energy actually needed to assist in bringing the hot water to the hydrothermal powerplant at the top (have you calculated it, taking into account the pressure differences between the bottom of the ocean and the surface?). You do mention on your site that the pump motor(s) would be powered by excess generated power from the hydrothermal plant, and although this is not an over-unity design I am wondering if you have a good grasp of how much power is going to be needed compared to how much power will actually be generated. Can you provide more details on your calculated (or estimated) system input power VS output power for further discussion please?

Also, the heat transfer arrangement of the closed loop system solves some problems, but heat transfer is going to take a long time and even with a labyrinth style arrangement near the vent (exposing more pipe surface area to the superheated water for faster heating) the vent area is rather small. Can you provide more details on your calculated (or estimated) heat transfer and fluid flow rate for the closed loop system for further discussion please?

These are two of the main potential stumbling blocks that I can immediately see that would cause issues when transferring from a theoretical to practical power generation design (and you certainly wouldn't be the first to fall into this trap). I am sure there will be more, but it is an interesting design none-the-less that deserves some time spent on further discussion and a more detailed concept verification (or further development).

Another great question.

While the concept is similar to geothermal in that the Earth itself provides the heat source, geothermal designs require drilling and water injection, while hydrothermal does not. Also, the temperatures attainable from hydrothermal vents are 3x higher or more.

There is no external energy required to assist bringing the hydrothermal fluid to the surface. While that may seem counter-intuitive, computer modeling has borne this out.

The main mechanisms involved are vent flow velocity (1-5 m/sec), and the intense heat of the fluid. Through both convection and conduction, as well as steam pressure derived as the fluid rises and the ambient pressure is reduced, the superheated fluid makes its way to the surface without outside assistance. It's important to remember that there are 73.5 MCalories/second of heat energy being pumped into that pipe, and the density of the fluid is far lower than sea water.

One of the largest oil companies in the world has run the computer modeling, and these are their findings.

Assumptions:

Seawater Specific Gravity 1.03
2,500 m depth
3740 psi (258 bar) ambient pressure
350C vent temp
Surface vent temp 340^o C
Perfect insulation
12.13" (31 cm) ID pipe diameter
50% efficiency of steam turbine
Ocean temp at bottom 2^oC
Surface ambient 15^oC
Platform 30m above water line


Findings:

83 MW energy producible
>100m/sec (218 mph or 360 kph) steam velocity at surface
Useful surface temp 340^o C
Useful surface pressure 70 bar (1015 psi)
25-35 kg solid/ton
25,000 tons/day delivered to surface
30 KT/day steam (25,000m³)
25,000 tons x 25-35kg= 625,000 kg- 875,000 kg solids per day

If you divide the area of the 31 cm pipe (855 cm²) into the 83 MW producible energy, you get approximately 1 MW producible/10 cm² pipe area.

And of course there is nothing over-unity claimed, anticipated, or even needed. There is an abundance of energy available to do whatever might be needed, but pumping is not anticipated.

Regarding the heat exchanger question, there are two different points to ponder. First, those vents that are located near Seattle are absolutely huge, as big as 30m in diameter! I can't even imagine a hole in the ocean floor of that size pumping out superheated water, but that is what reliable sources have published. http://www.agu.org/revgeophys/humphr01/node4.html

Obviously, it would be no problem in a vent that size to just submerge the pipe within the vent.

Those vents are the exception, however, and you're right. Most are fairly small, but they are generally located in a vent field where many vents are in close proximity to each other. Using a similar design to that shown in my animation and capturing the output of several vents and feeding it into a manifold, a large volume of hydrothermal fluid can be collected and utilized to surround a heat exchanger.

If you have other questions I'll be glad to answer them.

It sounds great in theory.

What materials do you plan to use for your structure in this highly corrosive environment?

What happens to the structure when the Tectonic plates shift/move?

I saw some contradictory statements...

the energy is constant. In fact, it is the only green energy source that works 24/7/365 with equal intensity.

and

As one vent system closes, a new one will open at a previously frigid and barren point on the sea bed.

So Would you have to chase these ever-changing vents around the ocean floor?

The energy potential is large enough to warrant a closer look, but I'm not sure about the real feasibility of maintaining a structure at the bottom of the ocean in the most inhospitable locations on earth. Keep it up, maybe one day we can design a system such as what you propose which is feasible, and easily maintained to aid in the reduction of non-sustainable energy sources.

I'm enjoying this forum. More thought provoking questions.

Materials will be decided by the system developer, but I would almost bet that the same materials used in geothermal will prove most practical.

The tectonic plates move at about the rate that a human fingernail grows, so plate movements can certainly be accomodated with corresponding shifts in the platform position.

There's nothing contradictory about what I'm offering.

The mechanism that drives the vents is nothing more than the weight of the water above, constantly being forced down into cracks in the crust. That water eventually finds its way to the magma where it is superheated and returned to the ocean as a hydrothermal vent. For that reason, the energy output is also constant. There is no fluctuating input, so the output is constant as well.

There's a difference between constancy and being perpetual, and they are definitely not perpetual.

While the vent is where it is, the energy output remains constant, but at some point it will close, as have all others before it, and a new vent will open. I envision the system simply being dismantled and moved to the new location, which could reasonably be expected within a few hundred yards of the original site.

The great thing about this system is its simplicity. I mean, what's the MTBF on a pipe?

There are no moving parts or sophisticated components below the surface save a valve to redirect the flow away from the pipe.

I'm quite convinced that almost nothing totally new has to be developed. We're using existing pipe technology (if not actual existing pipe), existing construction techniques, existing oil platforms, existing generators, and existing undersea cable. That's one of the things that makes it so attractive. This can be built quite rapidly with the funding and the will.

1) What percentage of heat is transformed into "billable" energy by the company operating?

2) What is impact of balance of heat upon release to local environment?

3) A wee bit of mercury in coal ash gets people all whooped up, Can hardly wait to see their excitement at your heavy metal cocktail insitu.

4) I'll save my further comments until I can give your website a serious consideration.

5 Congratulations on the patent.

6) Good luck on the business plan and permitting.

Milo

Well, the answer to your question about billable energy is that it's fundamentally irrelevant because the energy is free. Look at the computer model figures I posted, and you'll see that the output after generator losses is estimated to be 83 MW. That's the billable figure, and the rest matters not. I'm sure there's academic interest in the answer, but the only important number is what's usable.

The heat release balance will have to be calculated if it's needed, but I envision leftover heated water being returned back to the bottom of the ocean and not dumped on the surface.

My heavy metal cocktail has always been at the bottom of the ocean. There's a return pipe which allows unneeded materials to be returned to the depths. I advocate very strict controls on what can be disposed of this way. It's not a trash dump. But there's no reason I can see not to allow materials which originated and would have been expelled into the ocean to return there.

Thanks for the good wishes.

Hi bc:

The question was raised about the energy cost to raise the heat to the surface, and I see pumps in your sketches. Surely with a design of an inner insulated pipe, and a outer pipe subjected to the cooling of effect of the ocean, the heat conveyed by an appropriate medium could be accomplish by convection? This of cause also applies to two pipes, one insulated and the other subject to cooling?

Regards JD.

There are two pumps envisioned. One is the thermal enhancement pump, and the other is the waste return pump.

Heat energy content is dependent on temperature differential. If the ambient temperature is 15^oC and the vent temperature is 350^oC, then the working differential is 335^oC.

The thermal enhancement pipe is like a huge insulated drinking straw inserted in the ocean, to a level below the thermocline. That's a layer found in any deep body of water, above which the water is relatively warm, and below which it's extremely cold. That water is so dense and cold that it simply has no energy to rise.

The thermal enhancement pipe extends down into this water which is just a degree or two above freezing, and water is pumped from the surface of the water within the pipe to the platform (30 m in the case of the computer model). As water is withdrawn from within the drinking straw, it is refilled by atmospheric pressure at the only point open to the sea, with the frigid water from the depths. That water is then utilized for the cold side of any heat extraction process, increasing the amount of available energy.

So in exchange for the energy expended to pump those 30m, I have increased the temperature differential from 335^_o C to 348^_o C. That differential, when plugged into the numbers from the computer model, translates to 6 MW on just that 12 inch pipe! The output jumps 6% on this very small and very conservative model, to 89 MW, and all we're doing to get that increase is pumping water from the sea surface to the platform.

The Waste Return Pump is simply used to push any unneeded, leftover materials that originated at the bottom of the ocean back to where they came from.

Neither pump is there to raise the hydrothermal fluid to the surface. As stated earlier, that has been demonstrated to be unnecessary. The convection occurs naturally, but the huge temperature differential between the inside and outside of the pipe can be utilized with thermovoltaics, which may eliminate the need for a steam turbine altogether.

I like this subject, I gave it 5 stars.

I like it when CR4 has a topic and a plan that could actually work. As stated above, there are daunting problems that need to be solved, or at least addressed.

No doubt, there is a huge amount of energy down there. But there is much accessible geothermal energy available from the land too. It might be less costly to run a pipe to the bottom of the ocean, than drilling for miles. However, working at sea creates many problems too.

Anyway, looking from the very front end, is it not true that we know so little of the sea floor? It would seem that much research should go into the best place for such an endeavor. What data do you call upon for the location of such devices?

This is far from my field. And, I suppose I can't offer much but an interest, and a bunch of academic questions. But I like thinking about stuff like this, _{(when I'm not thinking about women and glasses of beer).}

Oh ya, and, when French and British submarines aren't busy bumping into each other, how you gonna keep them from bumping into you equipment? _{(Sorry, ignore that last remark, I just couldn't resist. Stop by and I'll pour you a single malt too).}

Hydrothermal vents were first discovered in 1977, so we actually have over 30 years' data on them and they are fairly well known. Research submarines and remote vehicles have made many trips to different vents, so even though there are thousands of miles that are still unexplored, those that have been documented have usually been visited several times.

Geothermal energy is very good, and if you read my posts in the other discussion, you know that I'm strongly in favor of using them over wind. There's simply no comparison between the two when looking at the grid.

Hydrothermal vents are literally orders of magnitude more powerful than geothermal systems. The Geysers, the geothermal plant in Northern California operated by Calpine, has 19 plants that generate a total of about 1 GW of clean, reliable, base-load compatible energy.

Based on the figures I gave earlier, with 1 MW/10 cm² of pipe area, I'd need 10,000 cm² of pipe area to produce that same 1 GW. That's a pipe diameter of a little over one meter.

When looking at the vents off of Seattle, it's easy to see a 3m pipe being utilized, and now we're up into the stratosphere. We're talking 8 GW using the exact same temperature figures shown, which are conservative, and that's without the thermal enhancement pipe. If you use that, the number jumps by 375 MW! And that's just by increasing the temperature differential by 13^o C.

The research I'm relying on has already been done by groups such as Woods Hole, NOAA, and other reputable scientific organizations. I have not done any primary research on the vents themselves.

Thanks for putting a new thread up on this Bc. Like I mentioned in the other I'm trying to learn as much as I can on this and for now I'm just going to read what you all have talked about and may have questions later. Thanks again.

Thanks for the comments.

And since we're such good friends, you can just call me B.

Just kidding. My name's Bruce.

You've probably thought of this... but I wonder if you this wouldn't be a good application for an MHD (magnetohydrodynamic or caterpillar) pump, due to the temperature and metallic content of the fluid you are pumping. I think if it could be made to work then it would save replacing pump seals and rotors every 5 minutes.

I'm still very impressed by the website. Congratulations on the patent. I believe this will become a reality, not just because of the energy in the earth, but more because of the energy you have and are putting into it. Exemplary.

Chris.

MHD is explicitly mentioned in the patent as one possible form of utilization of the energy.

I'm already convinced that the first implementation will employ conventional generation techniques, but I'm equally convinced that will change as confidence improves.

My patent only covers the basic vehicle that ducts the hydrothermal flow to the surface. I intentionally left out anything more than a brief description of possibilities for power generation once it arrives.

Thanks for the encouraging words.

Hi Bruce,

The last company (Lee Specialties) I worked for manufactured wireline tools for oilwell measurement. While your temperatures are higher, the methods of measuring pressure, temperature and flow are probably applicable, and so some fo the tools and technologies might be as well. these tools are good for 300F/175C but you may be able to interest Jim Lee in designing manufacturing tools to work in your temperature applications. That would give you the ability to assess specifically any particular vent. They and others, do make tools for "Open Hole" applicatons (as opposed to Cased Hole, which is Lee's main focus) They manufacture hydraulic grease injection systems that allows them to measure systems with a wellbore pressure up to 15K psi.

Chris

Thanks for your thoughts, but it won't be something I'll pursue.

The reason is that I'm not developing or engineering the system. I have simply patented the vehicle and am now in the process of licensing it to as many companies as I can. It is those companies that will be doing the actual system development, ordering or making tools, and the like, not me.

This is far too big for any one individual. It will require large organizations with lots of money and engineering talent to take it from concept to reality.

Great site and good work!

I remember, when I first heard of hydrothermal vents, that I wondered whether or not it would be feasible to tap into the energy. After hearing that the "soup" spewing from the vents was a toxic and corrosive mix of chemicals, I guess I quit thinking about it any more.

Has anyone approached you about a license to use the technology?

I wish you much success, and good job for working out a method to produce usable energy from the earth's throw-away energy!

Bill

It was such an obvious solution I was actually surprised that no one else had thought of it, but my patent search turned up no other references to hydrothermal energy.

I'm not too worried about the vent content. That's an engineering problem, and I'm sure with the right minds working on it it will be resolvable quickly.

I've had approaches from many different groups, but nothing is signed yet. I'm still working on it!

Thanks for the good ishes.

I must have missed it. What is your patent number?

The patent is pending. 11/890735. It was published last month.

to be found if

20090013690

is searched for in the http://patft.uspto.gov/

and searched in AppFT, application numebr search.

RHABE

Congratulations ¡

The real issue is to find the money needed to put into practice you excellent idea.

In principle, I think it is much more reasonable to invest money in the development of your idea than to do it to capture the CO2 produced by the combustion of crude, coal, wood etc.

I hope you will succeed because the theoretical basis of your idea is correct.

From now on, I am a fan of your project. I would like to be involved in it.

Best regards,

Arturo Pérez Rodríguez

Dr. Industrial Engineer.

Pues, gracias, Arturo. Hay fuentes en el Mediterraneo que puden ser utilizados por España para energía y agua dulce.

I'm glad you're enthusiastic about this system. Spain is one of the countries that could benefit immensely from vent utilization because of the severe drought you're experiencing. I approached the Spanish government about this twice, but got no response. The email address to which I wrote was gabinete@presidencia.gob.es. Perhaps if a Spanish citizen were to write to the same address it might make a difference.

I spent a lot of time traveling in Spain and I love it there. I speak the language fluently and believe that there is great potential for vent utilization.

For those who believe in the potential of hydrothermal energy, I'd appreciate any efforts on my behalf in getting it known to media or to government or private concerns. Some of the best funded interests in the world would prefer that I not do what I'm doing, and all help would be appreciated.

Just out of curiosity is there a rough estimate how economical (cheap or expensive) power would be generated this way?

I assume this virtual floating power station probably wouldn't cost much more than an oil-rig to construct but still, over time due to maintenance and other on going costs, how economical could it be to compete against other types of power stations?

I always thought seizing geothermal energy should have been done right from the moment it was discovered let alone something like this.

Good luck!

This statement: "flash to steam" is to be extended to an optimum heat exchanger that is better with fluid or wet steam.

Then cool but still high pressure water will remain transporting or sedimenting considerable amounts of minerals to be separated from the high pressure water.

Then maybe extract more energy with a Pelton turbine from the high pressure water (4000m is a good energy to gain).

RHABE

The basic concept is to keep the pipe pressurized until the steam escapes at the top. I published the findings of the computer model earlier here, and there is great steam pressure and velocity available.

I've made no attempt to engineer out every problem that might come up. I have patented the concept...the basic vehicle that allows hydrothermal energy to be captured and utilized. I'm fully aware that there is a lot of designing and engineering to be done before the first system can be installed, but that will be done by those who license the system.

It's quite obvious that the physics behind my concept are sound, and that it is do-able. Now it's a matter of getting the money interests involved to transform the concept into a reality.

I'm all for developing useful technologies based on what is available...The discovery of deep ocean vents in 1977 reminds me of the discovery of the Americas by our European "founders"..The already there inhabitants who had at the time a large population base must still feel slighted at this terminology...I suspect the deep sea vents throughout our globes oceans have some modifying role to play in the planets heat balance..I do know that the biology of those areas has and is studied extensively yielding a new kingdom of life ,the Archea, becoming known to we humans...Since then archea have been found in every growing numbers everywhere...Not to be gaianeit..well yea to be Gaia-nist (vs unadultered capitalist seeing just the money potential)tread carfeully..These are big powers and while they are apparently everywhere their functional role is yet poorly understood.

Again,knowledge does not come from nothing..It is built up with many inputs...Iknow little of plumbing but steam pipes in large systems require constructs to prevent/absorb kicking and knocking to avoid structural catastrophe...2500 meters is a long verticality to overcome with pressure changes/currents/storm surges etc..Good luck..

Marty Wolf

Thanks again to all of you for your encouragement and kind words.

I'm concerned about the ecological impact as well, but I do consider it to be minimal. I say that because of the scale of the Mid-Ocean Ridge systems worldwide, covering about 65,000 km. Only a very small fraction of those vents will ever be considered for human utilization, and a smaller fraction still will eventually be harnessed. For that reason, I think any heat balance concerns are counterbalanced by the damage any competing system producing a similar amount of energy might create.

Nothing humans have ever done has been without some environmental impact, and this is no exception. It's not perfect, but it is reasonable when considering the exponentially growing demand for energy that must be filled from somewhere.

And I agree that 2500 m is a long ways to go, but it's certainly within the realm of what can be considered possible with today's technology.

I'm missing something. Please clarify.

You show that there are three vertical pipes:

One is open at the bottom and collects hot water from the vent. The density of the hot water is less than the sea in general, so, if the hydrostatic pressure at the bottom is equal to the hydrostatic pressure of the sea, then the pressure in the pipe at the surface will be less than atmospheric, and the hot water will boil and spew, naturally, from the open top. What am I missing here? Do you expect the hot water to flash into steam at some depth and arrive at the surface as somewhat cooled, by expansion, steam at low pressure, using only the heat (via heat exchanger) and not the pressure of the natural steam? If you want liquid hot water at the top of the pipe, it will have to be under pressure. That pressure, added to the hydrostatic pressure of the pipe full of water, would reverse the flow, would it not?

A second pipe brings cold water from the bottom to the surface to maximize the temperature difference between the hot water/steam and the condneser temperature. The cold water is more dense than the sea around the pipe. How do you lift the extra weight? You explain it, I'm sure, but I don't see it on your site. You show a pump on the oil platform, but how do you "suck" water up?

The third pipe has to handle the cooled hot water, "waste" minerals, the warmed cooling water, and the condensed steam. Since the density of this warmish waste water will be less than the sea, it will require energy to pump it downward, right? You show a pump in the diagram, but won't it consume a great deal of energy?

Clearly you have put a lot of thought into this, and I'm missing something. Could you, perhaps, tag your diagram with pressures, etc., so we can see how the plumbing works?

You asked, "One is open at the bottom and collects hot water from the vent. The density of the hot water is less than the sea in general, so, if the hydrostatic pressure at the bottom is equal to the hydrostatic pressure of the sea, then the pressure in the pipe at the surface will be less than atmospheric, and the hot water will boil and spew, naturally, from the open top. What am I missing here?"

You're missing the throttle valve at the top across which the water flashes to steam in a controlled fashion. That maintains pressure within the pipe, probably higher than the surrounding water pressure.

"A second pipe brings cold water from the bottom to the surface to maximize the temperature difference between the hot water/steam and the condneser temperature. The cold water is more dense than the sea around the pipe. How do you lift the extra weight? You explain it, I'm sure, but I don't see it on your site. You show a pump on the oil platform, but how do you "suck" water up?"

Very astute. The drawing is wrong, (but the verbal description is correct) but I went with it anyway because it seemed easier to understand.

Imagine this large insulated drinking straw extending below the thermocline, open at both the top and the bottom. The top edge would extend several feet above the ocean surface to prevent the pipe's contents from mixing with the surrounding water.

I envision the pump to be floating on that open surface within the "straw", drawing the water only from the surface to the input of the pump. The output of the pump will be carried to the platform 30 m or so above the surface. I'm not actually "sucking up" the water to the platform, but pushing it up.

As water is withdrawn from the surface, obviously the water level inside the "straw" will remain equal with the sea, and that is accomplished because it is refilled at the only point open to the water, with frigid water from below the thermocline. In a very short time the pipe will be filled with only nearly freezing water, and the only pump energy expended will be to pump the volume from the surface to the platform. As long as you recognize that the top of the "straw" is open to the atmosphere, you can see that I'm not actually drawing from the bottom but instead from the surface. That small amount of energy translates to huge gains because of the increased temperature differential.

"The third pipe has to handle the cooled hot water, "waste" minerals, the warmed cooling water, and the condensed steam. Since the density of this warmish waste water will be less than the sea, it will require energy to pump it downward, right? You show a pump in the diagram, but won't it consume a great deal of energy?"

It will require some energy to be consumed in returning that material to the depths, but we are dealing with an abundance of energy at the surface. The warmer waste water can be mixed with surface water to cool it even more, but it will require some work to get it down to the lower levels. I'm not convinced that the waste material has to be returned below the thermocline, and if it does not, then considerably less energy will be required to do the job.

Hi,

you wrote

"You're missing the throttle valve at the top across which the water flashes to steam in a controlled fashion. That maintains pressure within the pipe, probably higher than the surrounding water pressure."

As the temperature in the pipe is high and as density of hot water is much less than density of cold water I expect the major part of pressure difference from temperature, the throttle valve preventing steaming in the pipe.

But some steaming may be useful as the bubbles will lower the density and give upwards push.

Rough and quick estimate of pressure that is at sea-level exit:

http://www.lsbu.ac.uk/water/phase.html used for data:

If the water is at 20MPa pressure (2 km deep) and 300°C temperature then the density is near 0.75.

If this temperature is the mean between bottom and top then there would be a pressure of the hot pipe at sea-level of 50 bar. (1/4 of the water column as densities are 1 and 0.75 would be 500m of water) .

This is a pretty good pressure/temperature relation.

Then a statement:

"A second pipe brings cold water from the bottom to the surface to maximize the temperature difference between the hot water/steam and the condenser temperature"

this will need much less pressure to bring up as temperature difference is somewhere near 20 °C. The change in density by temperature is near 10Kg/m³/20°C. (1%)

As the oceans are warm only near the surface only a fraction of the length is working in generating a pressure difference - may be only 50 to 100m. This is likely to be negligible.

More important: pressure difference by velocity. (Both in the hot and in the cold pipe.)

Next:

"The third pipe has to handle the cooled hot water,"

This may bring more difficulties if brought down without prior cooling.

As the minerals have to be collected there will be a large open pond where this cools down to ambient, minerals precipitated and as cool water in pipe without insulation cooling rapidly at depth: no problem again.

So may be that pipe diameter/pressure loss by velocity is an issue.

Who will comment on this?

RHABE

I already offered the computer model figures, and it was run by a huge organization known worldwide.

Your calculations are off a little bit. The expectations are 30 KT steam daily at a useful surface pressure 70 bar (1015 psi)

You've apparently misunderstood the concept of the Thermal Enhancement Pipe. I'm not bringing the water up the way you envision it. I'll try a different way to explain it.

Imagine firefighters dealing with a forest fire near a lake. They toss input hoses into the surface of the lake which feed gasoline-powered pumps on the shore, and the water is then used to extinguish the fire.

In this scenario, I'm sure you'd agree that it wouldn't matter if the lake were 3 or 300m deep. You're drawing water only off the top from the level of the surface to the input of the pump.

Now let's return to the TEP. We have this large, open-ended insulated drinking straw inserted into the ocean, with the top end extending a meter or two out of the water to prevent the water inside from mixing with the surrounding water, and the bottom end extending down below the thermocline.

Let's not do anything but look at the pipe right now. Of course, you'll see the level of water inside the open top end equal to the level of the ocean itself.

Now let's scoop a bucket of water out of the area inside the pipe. Of course the level inside the pipe won't be one bucket-load lower than the sea. If it were sealed at the bottom, then the level inside would be lower, but it will remain equal because the atmospheric pressure has replaced that bucket of water with cold water at the only place it can enter the "straw", at the bottom.

You're envisioning that TEP as a long input to the pump, and that is incorrect. The pump's input is sitting on the surface drawing water off the top of an area that's open at the top but separated from the surrounding water. Any water withdrawn will only require the same amount of energy to pump it as another similar pump would use sitting a short distance away outside the pipe drawing from the surface of the ocean would need. The difference is that as the pipe refills it is refilled with extremely cold water, but the energy required to bring it up from the depths is provided by nature. As soon as the total volume of water contained within the "straw" has been pumped, the only thing left within it is frigid water from below, yet the level will still remain equal to the surrounding sea.

I hope that's clearer.

I expect that some energy will be expended to push the warmed water and sediment back below the surface, but it's got to be assumed as part of the overall balance that is recoverable from the system as a whole, since it's a necessary part of what we're doing. I'm fairly certain there would be a lot of environmental issues raised if the water and sediment were simply dumped on the surface.

I do envision mixing that warmed water with surface water before returning it to the bottom. While that will require pumping a greater volume (water from the vent+cooling water from the surface), the density would be much greater because of the lower temperature. Calculations would have to be done to decide what is the most efficient mix that requires the lowest amount of energy expended to get the job done.

Water from within the Thermal Enhancement Pipe could also be used for this purpose, dramatically cooling the vent water, perhaps even making it colder than the surface sea temp where it would then fall naturally.

There's no limit to the volume of water that can be withdrawn from the TEP. You're just drawing it from the surface, and it's refilled at the bottom as fast as it's drawn from the top, no matter what that rate might be.

"Let's not do anything but look at the pipe right now. Of course, you'll see the level of water inside the open top end equal to the level of the ocean itself.

"Now let's scoop a bucket of water out of the area inside the pipe. Of course the level inside the pipe won't be one bucket-load lower than the sea. If it were sealed at the bottom, then the level inside would be lower, but it will remain equal because the atmospheric pressure has replaced that bucket of water with cold water at the only place it can enter the "straw", at the bottom."

IMHO, if this were so, it would be easy for me to drop a "straw" offshore and pump cold water to air-condition my beachfront hotel. I don't think it's that easy. I don't see the level of water inside the open top equal to the level of the ocean itself. Let us suppose the bottom end of the pipe is 1000 meters deep and open to the ocean water. (I'm trying to use round numbers for ease of calculation. Substitute better ones if you wish) The hydrostatic pressure of 1000 meters of ocean water will equal the hydrostatic pressure of water in the pipe. But, if the cold water in the pipe is 10 per cent more dense than the average sea water, there will be only about 900 meters of cold water in the pipe. You will have lift the cold water 100 meters to the surface, which requires a lot of pumping.

I just don't buy the assertion that the cold water will naturally fill the pipe up to the surface. An elementary school analogy would be a glass U-tube with mercury in the bottom. (I know we can't have mercury in classrooms any more, but in my day, every class had a mercury barometer.) Pour water in one arm of the U-tube. The denser mercury does not rise to the level of the water.

If I understand your assertion correctly, you're stating that the level of the water within the open top of the "straw" would be lower than that of the surrounding sea because of the higher density of the cold water.

I'm not sure that is correct, but let's assume that it is. It sounds like the worst-case scenario you're anticipating is the requirement to pump the water perhaps a couple of meters higher than would be needed to pump it from sea level. With the amount of energy available, that's surely a reasonable thing to do for the energy gain the temperature differential affords.

Whether you're right or wrong won't change the fact that there is a huge energy gain because of that temperature differential.

Using the same scenario modeled by computer, if the vent output temperature were 380^oC instead of 340, the output would jump from 83 to 93 MW without thermal enhancement. Now the additional 13^o of differential would offer 4 MW increase in output. It's a big difference for a few degrees, a difference that becomes even more impressive as the temperature rises.

I know I'm way out of my league here but it seems to me that it should be fairly simple to push the return water, which should be pretty dense (unless I am) due to whatever heavy metals and other sediments are in it.

A simple pipe (uninsulated this time) with an extra reservoire just above sea level should do it, using the same atmospheric presure differential and the cooling effect of the seawater on the pipe.

Hi,

"Any water withdrawn will only require the same amount of energy to pump it as another similar pump would use sitting a short distance away outside the pipe drawing from the surface of the ocean would need. The difference is that as the pipe refills it is refilled with extremely cold water, but the energy required to bring it up from the depths is provided by nature. As soon as the total volume of water contained within the "straw" has been pumped, the only thing left within it is frigid water from below, yet the level will still remain equal to the surrounding sea."

This is not correct. Cold water has a higher density than warm water.

So if you make a giant U-tube, one side cold, the other side warm, there will be the warmer level higher than the cold level.

Same with one cold pipe inside warmer water: level of cold water in pipe is lower if at equilibrium.

To bring up to sea-level you need pressure, to have throughput you need energy. Not really much, if significant, see my estimate.

"I do envision mixing that warmed water with surface water before returning it to the bottom. While that will require pumping a greater volume (water from the vent+cooling water from the surface), the density would be much greater because of the lower temperature. Calculations would have to be done to decide what is the most efficient mix that requires the lowest amount of energy expended to get the job done."

Not necessary. Warm water with partially dissolved minerals will be at the outlet of some heat exchanger. So let it cool further and let it oxidise at contact with air in a large pond. This will precipitate all (most) heavy minerals. Then let the water down with some natural pressure (from the height difference between pond and sea-level), cooling down further will be accomplished by rapid cooling inside a non-isolated pipe.

"Water from within the Thermal Enhancement Pipe could also be used for this purpose, dramatically cooling the vent water, perhaps even making it colder than the surface sea temp where it would then fall naturally."

That's ok. But very likely will need more cost and energy. Cost for tube size and energy for frictional loss.

Better to take what is nearby. But not really important.

Good to know: cost of insulated tubing.

RHABE

There is one thing that sets this system apart from almost any other system, and that's the abundance of energy available to do all sorts of tasks. There's likely more available than can be fed into the grid at any one point, and of course, there's no charge to create the energy used. That does make any additional energy consumed a lot more acceptable.

None of these issues changes the fact that the basic system is sound. I've never intended to solve every problem. The licensees will have to make the determinations as to which problems need attention and which do not. That's the difference between proposing a concept and making it work.

I understand that the engineers here want to think out every scenario and propose solutions, but I'm confident that any outstanding issue can be dealt with effectively. None seems to be beyond normal engineering boundaries in my view.

I really like the idea of letting the head pressure from platform height to sea surface be the pumping mechanism. That is the kind of beauty in simplicity that I find irresistable.

" ...cooling down further will be accomplished by rapid cooling inside a non-isolated pipe."

Don't count on it. With a pipe meters in diameter, I'll bet most of the water will never get near the frictional boundary layer, never mind losing heat by conduction. The deltaT across the pipe wall will be relatively small, too.

All of this discussion of warm and cold water being pumped up or down is really only necessary if one is not happy with a single pipe to conduct the hot water (violently) to the surface. Cooling with surface water and dumping the waste water at or near the surface will reduce thermal efficiency a bit, but thermal efficiency isn't all that important when the fuel (from the vent) is free, and the cost savings (one pipe instead of three) are great. Of course, the ecologists might be upset to have warm water and minerals dumped near the surface, where the phytoplanton live. They would very possibly cause "excessive" growth of organisms upon which valuable fish feed. Golly, free power and more cod too! Will Gaia ever forgive us?

I agree with your final paragraph, and with the physics of the first, but that would only hold with a heat exchanger concept. If the water were physically mixed together to drop the temperature what you're suggesting would not apply.

Glad to hear I made you laugh. I used to practice to be come a stand up comedian but failed miserably nd had to give up. CR4 is my only chance now.

My question - how much minerals would you expect to retrieve from this thermal water if you'd bring it to the top?

I just think this superheated water, if handled properly, could be better used during the cooling process for desalination than trying to get those minerals out, what do you think?

Keep up the good work. Maybe CR4 will provide the boost to your comedy career yet!

The concentrations of minerals and metals in the ores from the fluid is among the highest found anywhere on earth. Different vents have different concentrations of different elements, but generally speaking it's a very rich source indeed.

The computer model showed over 600,000 kg of solid material daily from a 31 cm pipe. That's a whole lot of ore!

I don't have to try to get the minerals out. They're left behind when the water flashes to steam. That's why my patent covers an energy system, a deep-ocean mining system, and a water desalination system. The other two are natural by-products of any one of those systems.

Thanx BC, have you read the Qs in my first reponse, all of them?

I think I did, but if I missed something you can ask again.

Just for curiosity is there a rough estimate how economical (cheap or expensive) power would be generated this way?

I assume this virtual floating power station probably wouldn't cost much more than an oil-rig to construct but still, over time due to maintenance and other on going costs, how economical can it be to compete against other types of power?

To be absolutely honest, I have no way to estimate the cost of energy produced from hydrothermal vents since the cost of the system is unknown. It's never been built yet.

There are a few things that I do know, however. I know that there is currently a nuclear plant under construction in Alberta, Canada, and the estimated cost is $6.2 billion. When you think of all the things involved in a nuclear plant, from containment structure to control assemblies to multiple redundant cooling systems, and add to that the uncertainties of long-term storage of waste and the cost and complexity of fuel production, it seems absolutely impossible to me that this system could come anywhere near that cost.

Please note that I'm simply referring to my own intuitive guess. That statement is not based on any hard numbers, but it does seem reasonable to conclude that the cost of the plant, and therefore the cost of the energy produced would be less. If a nuclear plant can be profitable, then a hydrothermal plant should be even more profitable.

This is all guesswork, but I think the premises upon which the guesses are based are reasonable and sound.

I fully agree with you, Bruce, I am an intuitive engineer, what makes me feel that your basic idea is worth of being studied, and eventually tested an developed.

I have the technological and scientific knowledge that allows me to understand the thermal estimations you did, and the questions and doubts many people have put on the table.

After considering all that, I think that what is needed is to design a rig, with the best available engineering and scientific calculations, and to test it, as it is always made with all the new industrial developments.

The problem is that in this case Bruce can not build the rig in his garage, as many of us do with our innovations.

Ánimo, adelante, Bruce ¡

Arturo

The beauty of this system is its intuitiveness. It simply makes sense, and I have no doubt that it will be built. Whether I'll ever make money on it is far less certain than the ultimate scientific acceptance of the Marshall Hydrothermal Recovery System.

As you've stated, one of the major drawbacks I face is that it's not possible to build a prototype. The prototype will be the first operational system because of the scale and the depths involved. It can't be done any other way.

So the first system operators will be big-time gamblers. They're going to have to put a lot of money on the table for the chance to roll the dice, but once it's proven there will be a stampede from everywhere to get hydrothermal energy to the people.

I do believe that it is inevitable. The only real question in my mind is when that will happen.

Estoy adelantando, paso por paso.

Hi,

main pipe:

31cm pipe, which velocity?

I made a rough calculation Re and pressure to transport (with your input of diameter 3m and velocity 3m/s),

result is that a much smaller pipe: 1.2m and a much higher velocity 15...20m/s is much more likely and much better.

Why: the pressure-difference from hot water inside and cold water outside will give enough push upwards, to pump this amount without any pump.

Caution: mineral content is not included.

Minimum pipe diameter may be essential for success, as near sea-level there is a considerable pressure difference from inside to outside.

This will require internal isolation (against thermal loss and against corrosion and against heating up the external pipe-wall and against infiltration of the thermal isolation with minerals).

So think about 1 to 2 cm wall thickness of outer pipe, then some cm of porous mineralic isolation filled with non-moving water and then the inner tube likely some inconel or similar corrosion resistant material.

Total weight will be minimum 500kg/m if not 1000.

At 10$/kg (very likely not enough, factor of 5 missing?), this is minimum 10 if not 100 million $$ per kilometer. This is not an obstacle for such a rich power source.

So very likely some air-filled (foam, cork) containers distributed along the pipe to compensate for most of this weight.

mineral content:

hydrothermal water underground can dissolve and transport minerals up to 10% of its weight, so any value between 1 and 10% will be a reasonable value.

So with your figures (3m diameter pipe with 3m/s velocity resulting in 20m³/s throughput) this will be 0.2 to 2m³ of minerals, at a mean density of 5 (may be more) this will be 1 to 10 tons per second!

Or 100,000 to 1 million tons per day. This would be a major ore supply! Difficult to separate, but easy to leach.

Seems to be too much? Anybody who has better estimates?

So every obstacle seems to be solvable:

only one question remaining (in my thinking): is there this much output from any (most) smokers? Or which area of spreading seafloor (without any smoker) has to be mined for hot water to have enough?

RHABE

Devil's Advocate here. You guys are not doing BCMarshal any favors by being yes men. How about some hard critique..................

Big problem #1

750,000 kg solids per day or ~ 520kg/minute Through a 31cm diameter pipe. Delivering 350 C water at 1015 psi.

What state is water at that pressure and temperature? Vapor........

Dry steam or wet steam? Dry, very dry.

How much of that 520KG per minute of solids through a 31cm diameter pipe will the steam carry?

Or better yet, how much of the solids will not be carried up with the steam?

Or really to the point.................. how short is the period of time between initial flow and subsequent cease due to pipe clogging?

The thing is at the ocean floor 350 c water is liquid, but soon after you begin the traverse up, losing one atmosphere of pressure every 33 feet, it flashes. By the time you are even 1/4 of the distance up you have superheated steam.

Don't think that keeping a lid on it with the throttle valve is going to keep it from flashing.

If you think you have that figured out, let me know and we will move on to chloride stress corrosion cracking, steam impingement corrosion, galvanic corrosion, and pitting corrosion.

By the way if you think Inconel, Incoloy, Monel, Hastelloy, alloy 20 or any other current high nickel alloy is going to save the day at these temperatures and pressures (in the pressence of chlorides, h2s, h2so4, AND metal ion at high velocity)............................ well they might save the day. just one day though. certainly not more than a week.

At these temperatures and pressures, even with just the chlorides in normal tap water, at any PH under 10, at those velocities, will eat holes through any schedule pipe of any of those materials in a matter of days..

Yes, clearly there are significant engineering challenges, but as the man said, it was not his intention to resolve those at this time. How do you think it should be done?

That's right!

These are the challenges for the constructing firm who's going to undertake the construction of this project as it will be an engineering feat, what ever way you looking at it, by the time it is finished.

One of the questions that requires some engineering is the fate of those solid particles. Will they fall back and clog the pipe, or will they be carried to the surface?

I believe that they'll be carried up, and that they can be assisted if necessary by the injection of compressed air at the bottom of the pipe, but let's take a worst-case scenario. Let's suppose that engineering studies show that the material will fill the pipe completely in a matter of hours or days.

That doesn't preclude the use of the system. It just means we have to resort to Plan B, the closed loop system, which carries no hydrothermal fluid to the surface at all. While that would not allow for water desalination or mining, it would still provide the energy.

You have to understand that I have patented the basic vehicle that has transformed hydrothermal vents from a curiosity into an energy source, but there are a thousand scenarios that must be engineered around, and the ones you've brought up are extremely valid and certainly will be investigated. However, I never attempted to solve every problem. The system operators will have to do those calculations and make those determinations.

I believe the basic physics of the system are sound. Sure, questions remain, but for the purposes of my patent I had to assume that all issues are resolvable. Had I not done so, and instead tried to solve every problem myself before moving forward with the patent, the idea would still be on a piece of paper with a hodge-podge of numbers scribbled around the margin.

Your questions are tough ones, and I don't mind saying that I don't have absolute answers to them. However, I'm doubtful that even with your tough questions you would suggest that I simply fold up my tent and go home. They need to be met head on, and dealt with one by one, the same way that science deals with any other complex issue.

I brought an unperfected system based on sound science to the world. I have neither the time nor the resources to provide exact answers as to alloys to be considered or pressure levels at every step of the way. Those things will have to be considered and answered, but no one would even be looking at solutions without the basic concept I introduced.

I'm not trying to dodge answering your questions, but if I have to choose between spending all my time resolving highly technical issues in fields that are not within my area of expertise (I'm not a chemical engineer or a metallurgist), or instead spending that time trying to get the system known to the world so that it can have a seat at the table of any energy discussion, it's clear that I have to do what I'm doing. So I must acknowledge that your questions are fair and reasonable, and I also agree that they must be asked and answered before the first system can be built.

However, I must also say that I've left these things to be argued out and eventually solved by the engineering teams that will surely be brought together for that purpose.

I'm not trying to get you to pack up your tent at all. Forgive me if that seemed like my intent. You ahve an great idea, and i want to discuss what iu see at the most pressing issues, not because i want it to fail, but because I want it to succeed.

So many people in this thread were discussing the open version of your system, but in practive your closed version is what will be made commercially viable. Unlike dealing with chlorides at these temperatures, and copious amounts of sediment, in steam.. you are dealing with fresh water steam plant technology that has been in use going on for almost a century. In a harsh environment, the proven reliable technology will garner the investment dollars.

Despite the obvious benefits of mining and water desalination, I've always imagined that the closed loop system will be the first one built. The most pressing need we have in a modern society is to provide enough energy to sustain it. Turn out the lights and we're back in the stone ages instantly.

The closed loop design allows the energy to be extracted with a minimum of engineering, and it has another side benefit. Because the hydrothermal fluid continues to be ejected into the ocean the vent life communities they sustain will not be damaged or destroyed.

I appreciate your comments immensely, and I understand that you want this to succeed. I hope we can remember back on this discussion at some point in the near future when news is released about the opening of the world's first hydrothermal electric generating system.

Hi,

you mixed up the data: not a 31cm pipe but a 120cm pipe.

Water is supercritical at exit of smoker, upper end of pipe to be restricted to let the pipe pressurised, else you will loose a lot of energy.

Not at all dry steam: supercritical water, can be converted to dry ? steam.

No pipe clogging as velocity will be more likely near 15m/s and particles are very fine or dissolved.

The precipitation of dissolved oxides and sulphides and silicates is taking place at mixture with much cooler seawater. This avoided will either take up the minerals in solution or some will precipitate and being swept up by velocity.

Not really a throttle valve will keep the water supercritical but a restrictor nozzle (Laval).

Chloride stress corrosion cracking: not existing in some good materials, mostly Ni-based alloys.

Steam impingement corrosion: may be up on the surface. There to be handled. But this will be a part of the heat exchanger problem.

Cool down the supercritical fluid water to ambient or a little above and heat up water that is suitable for turbines. Let the minerals precipitate inside the heat-exchanger and brought out to collect with the seawater out to atmosphere.

I am convinced that some of the existing alloys will survive these conditions for a long time. There are ample results from supercritical water experiments intended to burn organic toxic waste. There too is a considerable velocity a necessity.

If you are right with your prediction: then change the inner liner to ceramic. (That may pose some problems too.)

The pressure does not matter as the inner (warm) tube has to have the same pressure inside as outside. Only the outer tube (cool, high strength) will be highly stressed. And protected at the outside, either by coating or by galvanic protection or both.

If your scepticism (appreciated) proves to be true then there is the necessity to bring the heat exchanger down and bring up only clean pressurised water.

RHABE

why would you think this is a superheated liquid, there is no reason to believe that it stays in liquid form, it certainly is NOT free of impurities nor shocks. Look again at the pressure/temperature once you are 1km off the ocean floor. It is bone dry steam at that pressure and temperature, particulates are not in solution, but being forced up as if in a sand storm.......... and it will erode like a sandblaster.

Marshall knew what he was doing when he proposed the closed loop system, that wasn't just a whymsical, also-ran. It is the preeminent design.

chloride stress corrosion cracking most certainly IS present in all high nickel based alloys at these temperatures, it is of primary concern.

http://books.google.com/books?id=1_z-T12UMr4C&pg=PA137&lpg=PA137&dq=chloride+stress+corrosion+cracking+nickel&source=bl&ots=UNdsZd_uhG&sig=-fdLZca2s_NL5y8Gevb1qE-q0w4&hl=en&ei=XNujSYivJ5matweBqJHbBA&sa=X&oi=book_result&resnum=2&ct=result#PPA139,M1

I realize I had just initiated a; 'yes it it, no it isn't, yes it is, no it isn't' debate format, so here is a link concerning chloride stress corrosion cracking. Note that above about 280 C that even alloys with the highest nickel concentrations are subject to chloride stress corrosion cracking.

Thanks for taking the time to run the numbers.

The numbers are based on 3m/sec velocity. Since published figures show vent velocities at 1-5 m/sec, I simply chose the number in the middle. Obviously if actual velocities are higher or lower than that, then the figures would have to be adjusted.

While the higher velocity might be better, it's something I have no control over. I'm not anticipating pumping at the bottom, so the velocity is what it is. It isn't a controllable variable.

I've always anticipated more pressure inside the pipe than outside, especially near the surface. I've always visualized a double-walled pipe with insulation separating the walls, but that design is open to change should a more practical or less expensive method become available.

There's an amazing insulation called Aerogel which is extremely effective and very inexpensive. I believe this is an excellent choice for insulation material. http://en.wikipedia.org/wiki/Aerogel

The numbers that I have from the computer model suggest 25-35 kg of solid material from that 31 cm pipe is a reasonable expectation per ton of fluid expelled. Even on such a small pipe the total daily volume of ores and other solid materials would be 625-875 tons per day.

If I take the middle figure, 750 tons/day and divide it into the pipe area of 755 cm², it's clear that we're talking about 1 ton/day/cm² of pipe area. I see no reason why that figure can not be scaled up to provide a rough estimate of the solid volume from a larger black smoker carried inside a larger pipe.

A 1m pipe has an area of 7853 cm², so we can anticipate 7853 tons of solid material per day.

If we return to the model again using the middle figure, 30 kg/ton is a density of .03, well below any expectation for the solids to fall out of solution based on your figures.

Don't take the existing numbers of the black smokers as given.

These are resulting from seawater penetrating the seafloor and some of the superheated water coming up again and being restricted on its way by a lot of distributed resistances.

This will be realised with considerable different solutions as these resistances (flow- restrictors) will not be optimum for a technical system.

I think that a heater down will be very likely. This has to be optimised in context with any other component. The hood you are thinking about may be a solution to start with but not suited for an optimum solution.

If you want to use lower velocities then there will be excessive pipe diameter, cost, maintenance.

If you want to use higher velocities (centered around my figure of 15m/s) then for the 1.2m diameter tube this may be possible up to 30m/s.

But this is limited by the natural pumping that is generated by the density difference.

Nobody would want to operate a pump down there if this is possible without.

Another possibility I did not think about until now: let the supercritical water boil partially to further lower the mean density. This will boost the pumping capacity.

Double walled pipe will be a necessity.

Aerogel is not a choice, much too fragile.

Needed is a porous ceramic or glassy material that can be brought into shape and is stable in this shape. Inside this porosity will be water. Thermal conductivity is 0.7W/°K.m

This is ok for sufficient insulation. Smaller pipe diameter will help to reduce heat loss.

So next we would have to be ingenious about a bottom heat exchanger or a buried (inside seafloor rock) water collector. Maybe also about a water injector.

RHABE

RHABE..............

Just curious here, why would you want your porous ceramic material insulating between your double walled pipe to have the pours filled with water?

"porous ceramic material insulating between your double walled pipe to have the pours filled with water"

Hi benbenben,

I want to separate the inner tube from the stress that is generated by inside pressure.

So if the pressure drop by flow is negligible (below the 50bar I estimated for upward push generated by density difference) then the pipe will be subject to near constant pressure.

This assumes that also the temperature drop is negligible: achieved by high flow velocity and thermal insulation.

So near 15m/s at near 1m diameter will be an optimum. (If this amount of hot water is available.)

To achieve a low to negligible temperature loss the thermal insulation would need to match the following conditions:

A steel (ferritic or martensitic) pipe of 1.2m diameter has a circumference of 3.8m,

an assumed wall thickness of 2cm and a thermal conductivity of 70W/mK.

A surface area of 3.8m² and 2cm thickness will conduct (70W/mK)*3.8m²/0.02m or 13,300W/K, with 350K temperature difference this will be 13,300*350= 4.6MW heat-loss per meter of pipe length if only 2cm wall thickness of steel and outside staying cold.

(At 3km pipe length this would be near 1.5 GW.)

This is a factor of 1000 too much, so a factor of 3 to 4 shall be gained from a smaller tube diameter (for a first trial system). Or a factor of 3 to 4 better or thicker insulation.

A factor of 100 can be gained by using water (0.7 W/mK) and some porous ceramic (MgO or ZrO2 or SiO2).

The water shall give insulation and pressure on inner tube, so that the inner tube has inside and outside the same pressure (near the seafloor pressure).

This will relieve the stress corrosion requirements considerably as only 300 bar compressive stress radially acting on inner tube. Means for allowing for thermal expansion to be added.

So the outer tube will support the stress of pressure, the inner tube the temperature and salinity and acidity and the thermal insulation of ceramic foam beads the insulation.

So an additional factor of 3 needed: from using foamed ceramic beads (or hollow beads) and not too much water. 85% porous silica beads with 15% residual density will do this - no problem except some maybe dissolution at the hot side so there additional work to be done.

Ceramic insulation without water will not really transmit the pressure I want to have on the inner tube.

Inner to outer tube sealed everywhere except at the bottom.

Insulation to be fed with pressurised water at regular intervals (from below).

So may be 10 cm insulation is not at all enough, but enlarging the outer diameter will be a big cost factor as the outer pipe is subject to the full pressure.

So this is not an easy issue: 1.3m diameter (outside) and 3 cm estimated thickness will need 1000kg/m high quality steel for the outside tube. So 3000 tons total.

Steel cost estimate (outer tube only, no flanges, welding or else included):

maximum will be if made from maraging 300: near 50$/Kg (low volume) so maximum150 M$ - not at all too much for this type of powerplant.

Survival time of inner tube will decide on success or not: if your statement of "no such material existing" proves true then there will be a search for a passivating coating: pyrolytic carbon? What else may be possible?

RHABE

I don't like the idea of water that may flash to steam inside a porous material. Also, any chance to keep one side of the pipe dry, is far cheaper than wetting it on purpose.

The problem is the temperature and pressure in the presence of chlorides.

I believe a traditional closed lloop system has some advantages in gathering investment because it is proven technology.

The thing I keep having to remind myself is that maximizing efficiency of the heat provided is not what drives the cost down.

The heat provided is not like the heat provided by a fuel plant or even a solar or wind farm. Each of those carry a much higher degree of cost in the accessing the power, either in fuel costs, or photocell costs, or blade and tower costs.

The energy density is so high and there is no fuel charge, so the dominant costs are plant construction and maintanence. In this respect, a design that sacrifices carnot efficiency for cheaper construction and lower maintentance, will be more efficient in KW/$.

So other than a closed loop system....

A design using the leidenfrost effect might be employed to keep the temperature of the pipe below 250C (where inconel or incolloy or other high nickel alloy would better resist cl- stress corrosion cracking). leidenfrost effect describes the inefficient heat transfer process of film boiling (when you check a pan to see if it is ready to make pancakes, if the drops of water evaporate quickly it is not hot enough, but if they dance and stay around for a minute, then it si hot enough, that is the leidenfrost effect).

One way to employ this effect, a portion of the steam taken post-work and sufficiently cooled and relatively free to much of the impurities, yeilding relatively clean water, is pressurized, and injected tangentially into the pipe,, so that it spins on the polished inner wall as it mov3es up with the steam. Some very abrasion resistant hard material could also form flow control rings at intervals (imagine a taurus shape, just a bit smaller than the ID of the pipe with a teardrop cross section) to slow the speed of the boundary layer steam without causing excessibve turbulence.

If you can keep that boundary relatively smooth, you should be able to keep the pipe cool enough and free of abrasion. But it would require a stiff pipe, and that would be a lot of structure.

Another way to approach the problem is to convert much of the heat and pressure to kinetic very early while still near the ocean floor and drive a group of Tesla turbines with the high volume high velocity water at the top. Either one, or a series of eductor like peices could be fitted on the pipe, such that instead of high pressure high temperature steam, you have high volume high velocity water at much cooler temperatures. This would require a much larger pipe, but it is much cheaper to build a very large low pressure low temperature system, than a high pressure high temperature one, and the technology is here already. Tesla turbines have no blades per se, so are rugged and accepting of very mixed effluent. This has the benefit of involving no new technology, everything involved allows for years of working experince to be relied upon.

Another approach would be to convey long conducting rods through a structure built just to contain the flow of the vent (not pressurized). in service rods conduct heat to steam generators. While the rods are conveyed out of service, they are scraped to be cleaned and to mine the sediment.

Hi,

(have a look at "Water structure and science, by Martin Chaplin - magnificent! http://www.lsbu.ac.uk/water/anmlies.html

I agree that the temperature region between 230 and 300°C may be not feasible.

So to stay below 230°C may work. I agree.

But if you look at the (very peculiar) data of water, that is changing near the transition to a supercritical fluid from a polar solvent to a nonpolar solvent then my suggestion: stay above 300°C will be much clearer.

Leydenfrost: no way, too much heat lost, cold too soon.

"flash into steam" - not possible if pressure stays high. So only at failure.

I do not think that the loop is feasible today. The minerals will precipitate in the heat exchanger. These to bring down again will not make sense as you would not easily discard -with high cost- a mixture of valuable ores.

Loop ok but why? Let the warm water do extra benefits in heating or cooling or fresh-water production. Or let it out to some basin to attract fish.

Turbine down at seafloor is not working (turbines need low pressure at exit) without the complete infrastructure of a powerplant: Clean water (nearly no dissolved gas) to feed the turbines, expansion to low pressure, condensation to warm water.

So to benefit from the power density let the temperature and pressure stay high, convert to steam and water again in the heat exchanger (near or at surface level), or may be let the water cool down and the pressure to lower at the primary side of the heat exchanger and generate steam at the secondary only.

RHABE

Evidently, I didn't express my ideas clearly concerning the tesla turbine. I was not suggesting the turbine be below the surface, I was suggesting that the turbines be driven at the surface directly from seawater.. I was suggesting that a design that converts the heat to kinetic energy near the sea floor, yielding a high volume of high veliocity seawater at a much reduced temperature.

The point you seem to miss concerning the 'flash to steam' is that if sufficient pressure is kept to prevent steam, then no fluid will flow up the pipe. the sea water will be forced out around the pipe to seafloor intersection, or will not flow out the initial vent at all. Just do the calculation yourself. Look at the pressure required to keep 340C water liquid, now add to that the column of water at that temp and pressure.

concerning Leydenfrost.... are you suggeting that too much heat will be lost as the liquid coating the pipe walls is changed to steam???

Really?

Think about it.

Where did the heat go?

Concerning the closed loop system.............. It is funny that you see such dificulty with precipitates outside a heat exchanger, but have no problem with precipitates inside a proposed open system...

There are many types of heat exchangers. think outside the typical tube in shell design............

in your summary, you seem to miss the entire point of what was being proposed.................there is a serious problem attempting to contain and transport high pressure fluids with chlorides and sulfides at temperatures greater than 250C.

The suggestions I made were ideas that trade some carnot efficiency, for real world feasability.

I missed that point completely. How would you change the heat to a high volume of high velocity seawater? I'm quite interested in how you think that could be accomplished.

"I was suggesting that a design that converts the heat to kinetic energy near the sea floor, yielding a high volume of high velocity seawater at a much reduced temperature."

? I have no idea how this may be possible.

"The point you seem to miss concerning the 'flash to steam' is that if sufficient pressure is kept to prevent steam, then no fluid will flow up the pipe."

What about the difference in density? http://www.lsbu.ac.uk/water/phase.html

Have a look at this magnificent site: the density of water at the conditions of sea-mounts is below 800Kg/m³.

So there will be around 50bar of driving pressure if the pipe is filled to the top with hot, pressurised water.

My estimates in above posts are based on these 50 bar as driving pressure, so no pumping action needed. (Not included the much lower viscosity, have to do this soon.)

"concerning Leydenfrost.... are you suggesting that too much heat will be lost as the liquid coating the pipe walls is changed to steam???"

Yes indeed, on a hot plate I need near 100KW/m², this will give 300KW/m of (1m dia) pipe, or 0.9 GW per full length of 3KM : too much also if ample energy input is existing.

"in your summary, you seem to miss the entire point of what was being proposed.................there is a serious problem attempting to contain and transport high pressure fluids with chlorides and sulfides at temperatures greater than 250C."

The situation is totally different near and above the critical point.

Dissociation is greatly reduced. Dielectric constant is greatly reduced. Viscosity is greatly reduced.

I agree that the region from 200 to 250 °C is very critical with stress corrosion. That's why I suggested a pipe design that has only a compressive stress on the inner tube.

This together with reduced agressivity above 300°C will either solve the problem or need another inside coating of carbon. If this is working I have doubts. Woven carbon inner tube may work with polyimide converted to carbon to prevent solubility by decomposition.

So if your statement is correct: no such pipe possible, then I agree to your proposal to waste a considerable part of the energy and let the pipe operate at a suitable temperature.

In a not so near stage of development there may be the possibility to operate some high power Stirling Engines down to utilise the energy from heat (330 to 220°C?) and then get the cooler water and the generated electricity up.

Your ideas are difficult to realise, my ideas are difficult to realise: so wait and see or solve in the near future.

RHABE

One approach that might work even at the sea floor level, is a Sterling engine, driven by the temperature difference between the thermal vent and the cold ocean water at that level. Another benefit of this is that the water does not need to be moved much, and can still be returned to being the source of heat for creatures around the vent, just a few degrees cooler.

A shaft can be run to the surface as easily as a pipe.

Chris

While the temperature differential at the bottom of the ocean would be ideal for driving a Sterling, the problem as with all other previously envisioned plans, requires equipment to be placed in that inhospitable environment where servicing is nearly impossible. The beauty of my system is that the only component at the depths is pipe, with extremely high reliability.

There seems little doubt that a Stirling would work, but servicing would be a nightmare, and the largest Stirling made is only 1 MW.

you are right.. without a maintenance free device... its going to be a challenge for anything but pipe.. unless the whole system was able to be raised and lowered on a cable, and sit over the vent.

of all the heat engines out there, stirlings hold the potential to be the simplest, and therefore, most maintenance free... There are technical challenges to be overcome any way you do it.. not the least of which is periodic replacement of the pipe due to deterioration...

Chris.

You know, I really like the way you think. While none of us has all the answers (most especially me), I like the way you find the simplest ways of accomplishing things.

To me, simplicity is by far the most elegant solution to any problem. I've got several other very simple things up my sleeve for the future that are only awaiting some money to work with. I've already patented a system that replaces copper cable for long distance power transmission with a simple pipe, and I have a one-moving-part internal combustion engine waiting in the wings as well.

These things will have to wait, but hopefully not too long.

In the meantime, I would like to ask group participants to do whatever they can to help me publicize this idea. I need media exposure desperately, and if any of you knows reporters or has contact with media outlets of any kind, I'd surely appreciate any efforts to get it known.

Discovery Channel in the US and Canada usually enjoys news stories on new technology that will assist in power generation.

http://www.halfbakery.com/idea/Geothermal_20Power_20from_20Hydrothermal_20Vents

http://www.oar.noaa.gov/oceans/t_vents.html

Here are some results and speculations of hydrothermal vent research.

Fantastic possibility.

What about drilling at sites that have only very low biological activity? Water should be underseafloor everywhere and near ridges there should be ample heat.

RHABE

Look what've you done! His not responding anymore.

Yeah, dammit, look what you've done! And it's all your fault!

Thanks for the laugh. That's one of the funniest reactions I've seen.

As shocking as it may be, I really do have a life as well. I'll respond soon to the ones that take a little time to reply to.

Believe it or not, the halfbakery article was the only thing that the patent search returned! The concepts discussed there are essentially the only published thoughts on the utilization of hydrothermal energy before my system was revealed.

I did reply to that discussion at the very bottom, but I never got involved with it.

Your question about drilling is reasonable, and it may be utilized at some point. System operators will make that determination, but it certainly remains as a possibility.

The NOAA link is a very good one.

Historically, there have been several attempta at OTEC, using cold ocean water in contrast with warmer (surface) water to get energy. A recent issure of "Science and Technology" had an article, and there have been articles on and off for years, including in an 8th grade science text. Of course, using heated water from vents would greatly improve the economics.

The problem, historically, seems to have been the vulnerability of the pipes to storms or even human sabotage. Working from an oil platform should be easier than working from shore (as in Cuba) or working from a ship. Obviously, a ship trailing hundreds of meters of pipe is going to have difficulty coping with a big storm, whereas most oil rigs survive.

I wonder if there are not subscale feasibility experiments which could be tried. For example, get a cable-laying ship to lower a collecting cone on a flexible hose; it could be steered by thrusters or whatever by remote control and observed with TV. At least some of the vent water should make it to the surface, where mineral content could be analysed, etc. It could be funded as "basic science" with tax money, not venture capital.

Well,

The question there is, 'Who will benefit?' Will the taxpayers (doubtful)? Will the big corporation that takes on the project (maybe)? Will the big money cartel? (always - or it won't happen).

Otec, if employed with my method, would still only have that 13⁰ temp differential to work with. While it's certainly do-able and it has the advantages of something that can be set up anywhere, it would take many huge installations to generate one GW.

Everything I've suggested relies on existing technology, and the current state of the art in oil rigs is pretty stable and reliable, but as we all know, nothing is perfect.

If a feasibility study is to be done, someone else will do it. I haven't got the time. I need to move forward with licensing and let those interested parties do as they wish.

Dear Dr Marshall, Congratulations on your patent. This is the most exciting energy idea I've heard about since the 1980's, when I spent some time in Geothermal Energy research at LBNL under Prof. Paul Witherspoon. Although I know nothing about desalination and "mining", what you've described sounds equally attractive. I've read a few postings, some good, some not so good, but I sincerely believe you are on the right path; just sit back and wait for the idea to "spread", find lawyers you can trust, and sell your licenses to the highest bidders. If you ever need additional technical advice, I suggest you contact Prof. Adrian Bejan at Duke University (abejan@duke.edu). He has 18 honorary doctorate degrees--obviously one of the best minds in Engineering today. Good Luck, Bill Pope (retired engineer)

Thanks for the tip, Bill. I may just do that. That kind of knowledge and expertise is hard to come by.

I'm very fortunate to have found an excellent patent attorney. If anyone out there needs one, let me know. I had to go through two others before I finally found one that really knew what he was doing.

I'd like to correct one thing. I have no doctorate degree. I just didn't want that misperception to continue without me saying something, but I thank you for the compliment.

I have a question for the group. Does anyone know where I can get a new computer model done really, really cheap? I was not given the full data from the first model. I was only given the major findings verbally, but since I didn't pay for the modeling they figured I didn't need to have all the details.

Bruce

Try Chris from Alberta...His computer models on CR4 are phenomenal...Marty Wolf

I think he means mathematical model... But if you know the math Bruce, I can program it for you too. as well as images..

Chris

PS.. thank you Marty Wolf.

I already wrote a program that crunches the numbers to provide outputs based on certain chosen inputs, but I'm referring to the kind of computer modeling that allows the operation of the system to be predicted. It's far more complex than just a number crunching.

But thanks for the offer.

In any case this could be the ultimate solution to our energy demand on an unprecedented scale since it can supersede nuclear power stations in energy without the annoying nuclear waste.

Wow.

I must admit this is slightly concerning. Before you read any further as unqualified as I am this should be considered opinion.

From bcmarshal:

"The energy density is enormous, at least 3.3 x 10^6 more intense than solar radiation and the energy is constant. In fact, it is the only green energy source that works 24/7/365 with equal intensity."

What is your definition of constant? I mean for say the 25000 years sure the temperature will remain constant under current conditions (predevelopment of your technology). Have you explored the consequences of large scale development of your technology? For example let's say your technology is prototyped and works fantastically (as I have no doubt it will) and there is a world wide transition to maximise energy production by hydrothermal energy. As with oil investors and giant corporations seek out every location they can find, perhaps even opening new vents (it's is only a few kilometres).

Over a short time frame this system would seem capable to support us for a very long time, as several individuals once thought about oil reserves, but will this technology affect the systems in nature around it? Perhaps through heat loss, perhaps through mineral depletion, perhaps simply the amount of platforms in the water (this makes me think of that space junk news post yesterday).

The mineral depletion actually reminds me of a National Geographic documentary I saw quite some time ago about finding life in places previously thought impossible. I found two locations extremely interesting. One location was an extremely acidic stream and the other was a vent. These small creatures adapted to the heat and fed off the high mineral content in the seawater around the vent.

What effect will using this radiant heat normally dispersed into the ocean have on currents and sea temperature? Sure small scale might be negligible but with large scale it could have long term effects. Even lowering a point of a degree over a long time period can have devastating consequences.

Now initially this may seem insignificant but in recent years I hope everyone has come to see that even the smallest detail are connected to everything. What effect will disturbing this part of a perhaps extremely intricate food chain have? What happens to these minerals before your technology takes them out of the environment where they naturally occur? Do they get carried around the ocean feeding perhaps countless life forms?

Drinking water is a serious concern on a global level. While large scale desalination may be a good option it is not a solution, but this is a completely different topic.

Again forgive me for my ignorance, but you and others on this post seem extremely excited about applications and revenue generated by this technology but if I were in your shoes I would concern myself about long term consequences of the application, both large scale and small, of the technology before licensing it to anyone with the capital to develop it.

The last thing we need is in 100 or 500 years to find out that what we have done has caused another possibly global crisis. But then again if it is 500 years or more you won't be around to know.

Anyways this may seem all too unlikely or would only occur over a time frame that is too long to even consider, but why I said this is concerning isn't because of the things I can think of but what I can't. As a global community we need to carefully consider our choices for alternative energy.

From bcmarshal:

"Well, the answer to your question about billable energy is that it's fundamentally irrelevant because the energy is free."

And

"There's likely more available than can be fed into the grid at any one point, and of course, there's no charge to create the energy used. That does make any additional energy consumed a lot more acceptable."

Nothing is ever free.

Specifically here will be the possibly enormous costs of developing technology, construction of the platforms and the cost of transporting the energy from these vents to population centre.

My final thought as to why this is a serious concern is the dependability of delivery of the platforms. I'm sure a few of the members here will agree with me that they cursed out the price of oil as sever weather threatened the operation of oil platforms. Should any portion of our energy need be met by this technology will need a backup peaker plant system to match the capabilities. That or people just do with out.

For profit corporations this might be acceptable for society at large it becomes a waste of resources and capital.

And now where I am slightly qualified.

From bcmarshal:

"Using the same scenario modeled by computer, if the vent output temperature were 380^oC instead of 340, the output would jump from 83 to 93 MW without thermal enhancement. Now the additional 13^o of differential would offer 4 MW increase in output. It's a big difference for a few degrees, a difference that becomes even more impressive as the temperature rises."

You are talking about a few degrees difference in the 300-400 range; this will take some energy to heat.

From bcmarshal:

"There are a few things that I do know, however. I know that there is currently a nuclear plant under construction in Alberta, Canada, and the estimated cost is $6.2 billion. When you think of all the things involved in a nuclear plant, from containment structure to control assemblies to multiple redundant cooling systems, and add to that the uncertainties of long-term storage of waste and the cost and complexity of fuel production, it seems absolutely impossible to me that this system could come anywhere near that cost."

Yes but there are two things to consider with this. You are comparing a new undeveloped technology with no working prototype to the costs of a facility with years of refinements and large scale production to reduce costs. Perhaps after the first 10 or 20 platforms the manufacturing process will be of sufficient scale to reduce cost and enough of the complications worked out to make this extremely cost effective.

benbenben has covered a great deal of the issue I would bring up so no sense repeating them.

One question though, regardless of who is right on the weight of the solids per day from the vent, can the platform support the load? What will the cost be to move the minerals should they be exploited?

From bcmarshal:

"The current state of the art in oil rigs is pretty stable and reliable, but as we all know, nothing is perfect."

Yes this is reflected in our oil prices. (Disregard that)

From Isti80:

"In any case this could be the ultimate solution to our energy demand on an unprecedented scale"

That would be very unlikely.

Anyways none of this is meant to be negative just to open some topics up for discussion.

Great observations there. I'm glad you brought them up.

I'm not sure where to begin, so I'll just take them in order.

My definition of constancy is based on whether a source can fulfill society's requirements. A constant source is one that can provide society's base load generation at all times of the day or night. As long as fuel is available, coal, nuclear, oil, and gas plants are constant. Hydroelectric is constant as long as its fuel (adequate rain and water flow) is available.

Many of you migrated to this discussion from the wind energy topic, and I spoke out quite strongly against wind. That's not because I wouldn't love to get the clean, renewable energy that it offers, but because it is glaringly obvious that we can never switch away from the constant sources of power we're using now and replace them with wind generators. The basic power source, the wind, fluctuates dramatically and therefore the system output fluctuates as well. That is what I consider to be a rational, explainable, quantifiable, and ultimately disqualifiable reason, and that's why I oppose spending money on wind generation.

Solar power is another one. It doesn't take a rocket scientist to know the sun goes down at night and that solar panels won't work. It can never supply the constant base load, but it has one huge advantage over every other source. As the sun comes up and they start producing, it corresponds precisely with society's usage, which also increases during the day. For that reason, it makes clear, logical sense to invest in solar power, but only on the understanding that its primary function will remain mitigating peak demand.

I took a long road around to answer your question.

Hydrothermal vents are powered by a simple mechanism, the weight of the water above them. The enormous pressure is constantly forcing seawater into cracks and fissures, and that water wends its way through the earth, is superheated and then finally returns as that geyser that we've seen in videos.

For that reason both their source and their output is constant, and hydrothermal energy is fully capable of actually replacing nuclear, coal, gas, oil, and all the other dirty and wasteful forms of energy production we have now.

That's how I define constancy.

I don't mean to imply that every individual vent has an infinite life span, nor do I in anyway suggest that there are not serious challenges to be overcome, but hell...isn't that what engineers are for? That's what you're trained to do, what you spend your careers doing, and some of you will probably at some point be working out the tiny details that will make this system a reality. But work, it will. In over eighty postings by very intelligent and knowledgable people, I haven't heard anyone suggest that it won't.

Every one of us understands that there are serious issues to be addressed. Think about that very first nuclear power plant. It was understood that it had the potential to power cities and provide energy on an incomaprable scale. The basic physics were unquestionable.

In the exact same sense, hydrothermal energy only requires a commitment to make it a reality. The energy content is undeniable. It's there and we all know it's there. All we need is the will to do move forward.

The questions about nature are very important ones. I've made no effort to try to minimize the hazards, and in fact I made an early decision to confront the inevitable environmental questions head-on.

Look at the scale of the Mid-Ocean Ridge system. 65,000 km long. It's the biggest natural feature on the planet, yet we didn't even know the ridge was there until shortly after WWII. If you look at the maps of known vents on the animation and on my website, I think two things are reasonable to anticipate with hydrothermal energy utilization.

First, we can expect the vents that are the most accessible will be utilized first. The ones closest to land in places like Europe, China, the U.S., Japan, etc. will be the primary targets.

Second, I think that there will be a distance limit around those population centers beyond which the vents will be impractical to utilize, so there are a very finite number of vents or vent systems that will ever be under consideration for human control.

Given the scale of the system itself and the limited number of vents of interest to people, it's reasonable to conclude that only a small fraction of vents worldwide will ever be tapped even with maximum utilization.

While I know there are some environmental consequences to hydrothermal energy, I understand also that society needs and demands more energy, and it will be gotten from somewhere. For that reason, I think it's logical to focus on both the drawbacks of hydrothermal, and the comparative drawbacks of producing the same amount of energy from any other system.

As with many of the hard technical questions, I have to say that I simply don't know and I'm not qualified to predict what might occur with mineral depletion or heat loss, but I suspect that the impact will be minimal because such a small percentage will actually be tapped.

Also, if the closed loop design is ultimately selected, the only issue is the amount of heat removed. Biospheres are not destroyed, and minerals are not removed.

Wikipedia (http://en.wikipedia.org/wiki/Black_smoker) estimates that 1.4 × 10¹⁴ kg (370 trillion gallons) of water is passed through black smokers every year.

There's a decimal error in those numbers somewhere, and I don't know what the correct figure is, but if you convert the metric to US number, it will be 37 trillion, but if you convert the given US number to metric it would be 1.4 × 10¹⁵ kg. No matter which number is right, we're talking a huge amount of circulation. I don't think we can put much of a dent in that with hydrothermal energy utilization.

I didn't mean to imply that the energy is absolutely without cost when I stated that it is free, but once the system is built there is no additional ongoing cost to produce the energy.

As far as reliability of oil platforms is concerned, I agree with you. It most certainly is a serious concern. That doesn't stop them from being used and improved. I was contacted just last week by a company that builds very unique platforms that seem to be a quantum improvement over existing platforms, and it's just in time for hydrothermal usage. www.youtube.com/watch?v=J7xkdL0EdOA

I have created a concept, a vehicle by which hydrothermal energy can be harnessed. I've never stated that there are no problems or concerns with it.

Regarding my comment about OTEC, you suggested that the 13^o temperature differential I mentioned would take some energy to heat. That's not correct. That temperature differential comes from the cold water brought up from the depths through the Thermal Enhancement Pipe. While it will require some minor additional energy consumption to bring it up, that will be overwhelmed by the thermal advantage in the heat extraction process.

I know that I'm comparing a nascent technology with one that is developed and established when I compare hydrothermal to nuclear, and your conclusions are obvious. It will cost significantly more to build the first system than it will to build succeeding systems. I still can't conceive of it costing more than $3 billion, but I could be wrong on that. The final cost will only be known when they add up the numbers on the day the switch is thrown to send the power to shore.

I have been given platform load capacities at about 5,000 tons, and the video I posted is a modular design that allows multiple platforms to be installed together as one functional unit.

Hydrothermal energy is not the solution. It is a solution, and there is a difference.

Thanks for bringing up the points you did.

"In any case this could be the ultimate solution to our energy demand on an unprecedented scale"

I bloody well meant it too.

When I saw all the madness about the rapid development of those wind turbines offshore, in the north-sea, and recently a detailed controversial & damning study report by Dutch experts about it, who also thoroughly got involved in that venture, then there's no real renewable energy to look forward to in the near future on a large scale that otherwise we badly need.

As bcmarshall puts it on his website, the wind nd solar energies are inconsistent subject to the constant variations in the forces of nature.

When a renewable source of energy like Hydrothermal comes as abundant as this might as well seize it, if we can of course because this is what I meant by - this could be the ultimate solution - as long as the engineering challenges can be resolved, which I believe will be, there's no reason why it could not be the ultimate since it is more powerful than a nuke power station even.

Back in 2001, when I first saw those volcanic activities in the depths of the oceans through some documentaries nd not knowing anything about them before, even I always thought how nice it would be to be able to capture some of those energies!

Well, mr marshall seemingly has gotten further in this concept and all I can say good on him, however long it may take to accomplish this mission.

The only thing he (bcmarshall) still owes me with is - the estimate cost of generating power this way - would it be less for us (costumers) to buy or just as expensive as now and even more later?

By going through the Dutch study about those wind turbines they're just ain't my cup of tea any more nd I lost my faith and trust in renewables due to the enormous monopoly developing with them, including this one.

I wish I could offer you more than an educated guess when trying to answer your questions about the cost of the product to the consumers, but I can't.

Here's my guess, and please remember that it is only a guess.

I believe that it will cost less to build a hydrothermal plant than a comparable nuclear plant. It seems obvious that the ongoing operational expenses are lower, and there is no long-term waste handling and storage issue to deal with. Based on that, I have to believe that the cost of the end product will be lower.

I would love to have hard numbers to offer rather than guesses.