Off-Shore Electricity from Wind, Solar and Hydrogen Power

Off-shore wind-turbines generate electricity, as we all know. Now I’ll explain how off-shore solar and hydrogen can power our electricity too.

Solar at sea is easy. Simply mount photovoltaic panels on platforms isolated on their own or in the wide-open spaces between the off-shore wind turbines. Mount PV-panels high and dry but be sure to mount them below the height of the rotors of the wind turbines so as not to interfere with the wind flow.

Deep Sea Hydrogen Storage

Floating platforms can generate electricity from wind, sun or hydrogen gas, which can be stored in inflatable gas bags in deep sea water.
Floating platforms can generate electricity from wind, sun or hydrogen gas, which can be stored in inflatable gas bags in deep sea water.

The diagram shows how hydrogen gas can be used to store energy from renewable-energy platforms floating at sea by sending any surplus wind and solar electrical power down a sub-sea cable to power underwater high-pressure electrolysis to make compressed hydrogen to store in underwater inflatable gas-bags.

Later, when there is a lull in the wind or when it is dark, the hydrogen can be piped from the gas-bag up to the platform on the surface to fuel gas-fired turbine generators or hydrogen fuel cells to generate electricity on-demand in all weather conditions.


Air lifting bags for use in diving and salvage work, are available up to a volume of 50 metres-cubed.

Seaflex 50 tonne Air Lifting Bag

It should be possible to make much bigger gas-bags and anyway it is possible to rig multiple gas-bags together – for example, as shown in this diagram to rig 3 gas-bags together.

Three Gas Bag Rigging

Density of hydrogen gas with sea depth

Deeper seas are better because the water pressure is proportional to the depth allowing the hydrogen to be compressed more densely, so that more hydrogen and more energy can be stored in an inflatable gas-bag.

Density of hydrogen with sea depth

Click to view a larger image

Consider how many 50 m3 gas-bags we’d need to store the energy required to provide 1 MW of electrical power for 1 day – a useful amount of back-up energy to store to serve one floating platform.

1 MW for 1 day = 1 MJ/s x 60 x 60 x 24 = 86.4 GJ of electrical energy which can be generated from 86.4/e GJ of hydrogen energy of combustion where “e” is the efficiency of the hydrogen-to-power generator and can vary from 30% to 60% depending on the complexity and expense of the generator.

The combustion energy from 1 gram of hydrogen is 143 kJ.

So the mass of hydrogen with 86.4/e GJ of energy is
mass = 86.4 x 109 J / (143 x 103 J/gram x e)
mass = 604/e Kg of hydrogen to provide 1 MW of power for 1 day

Consider three scenarios – 50 m3 gas-bags floating on the surface, at 200 metres depth and at 2000 metres depth.

Surface density of hydrogen 0.1g/L
Volume = 604,000g / (0.1g/L x e) = 6,040,000/e L = 6040/e m3
= 121/e x 50 m3 gas-bags
for efficiency of 30% that’s 121/0.3 = 403 x 50m3 gas-bags – far too many gas-bags!

200m density of hydrogen 1.8g/L
Volume = 604,000g / (1.8g/L x e) – 335/e m3 = 6.7/e x 50 m3 gas-bags
for efficiency of 30% that’s 6.7/0.3 = 23 x 50m3 gas-bags – inconveniently many gas-bags.

2000m density of hydrogen 16 g/L
V = 604,000g / (16 g/L x e ) = 37.75/e m3 = 0.755/e x 50 m3 gas-bags
for efficiency of 30% that’s only 0.755/0.3 = 3 x 50 m3 gas-bags – a practical number of gas-bags.

So the advantage of depth in reducing the volume and therefore the number of gas-bags required to store a given mass and energy content of hydrogen is clear.

High-pressure electrolysis

I’m not sure if it is worth collecting the oxygen from the undersea electrolysis situation. I had in mind the option of just letting the oxygen gas bubble away.

One reason to store the oxygen would be to increase the efficiency and reduce the nitrogen oxide combustion by-products of hydrogen-fired generators. Whether that advantage is worth the cost of collecting the oxygen, I’m not sure.

Be aware that for undersea electrolysis in order to produce oxygen as the anode gas, a custom electrolyte solution will have to be used. If you try electrolysing sea water directly you get chlorine gas off at the anode, which is not so easy to dispose of and can be poisonous.

So the technique will be to separate the custom more-concentrated electrolyte solution from the sea water by a semi-permeable membrane and allow pure water to pass through it by osmosis from the relatively dilute sea water.

It’s worth pointing out that whereas we might describe this process as undersea “high-pressure” electrolysis, it is only so, “high-pressure”, because of the ambient high-pressure resulting from being under water at depth.

So there’s no high-pressure-vessel containment required for the electrolyte solution – as is required for high-pressure electrolysis which operates on the surface – and so undersea, a semi-permeable membrane is all that is required to keep the electrolyte solution contained.

Where is best for off-shore solar and hydrogen?

This “Atlas of Solar Power From Photo-Voltaic Panels” shows where on land and sea the most solar energy can be generated from a PV panel. (Reference – Fig 3. Global potential map of PV energy generation (Ypy) by c-Si PV module. Note – annual energy generation potential.)

Atlas of Solar Power from Photo-Voltaic Panels

Click to view a larger image

So for example, the area of sea off the west coast of north Africa, between the Canary Islands and the Cape Verde Islands, coloured orange in the Atlas of Solar Power and scoring 1,600 – 1,800 looks like the highest scoring area for off-shore solar power which is not too far from western Europe.

Even closer to Western Europe, there are plenty of areas of sea, coloured yellow in the atlas of solar power, around Spain and in the Mediterranean and scoring not quite so high at 1,400 – 1,600, but which are closer to Western Europe and so would mean shorter and cheaper connection cables.

Deeper seas, which are better for storing hydrogen in, can be found from an atlas of the oceans, such as this one.

Atlantic Ocean

Click to view a larger image

Looking at a close-up of the map for the area of sea closest to Scotland, Britain and Western Europe –

Sea depths near Europe

Click to view a larger image

– this shows that deep sea water most suitable for hydrogen storage is not to be found around the coast of the British Isles but depths greater than 4,000 metres can be found in vast areas of the Atlantic beginning a few hundred miles to the south-west in the Bay of Biscay.

So one area of sea which looks suitable for both solar and hydrogen powered electricity generation appears to be just to the west and south-west of the Canary Islands and to the north of the Cape Verde Islands. Whether this area is near enough to western Europe to be the best choice to supply western Europe considering the additional costs of longer interconnection cables remains to be estimated.

62 thoughts on “Off-Shore Electricity from Wind, Solar and Hydrogen Power”

  1. Interesting scheme. I suspect that the air bags would be too leaky for hydrogen. Smallest molecule. That kind of thing. That’s the biggest problem in transporting or storing of hydrogen. Perhaps look into the “ammonia” economy. Instead of producing hydrogen alone, combine it with nitrogen from the air. Then the molecule is too large to pass through the bag. From there separate the nitrogen back out (which provides another value stream as fertilizer for crops) before using the hydrogen in your engine. Of course a breached bag would release ammonia so that would be a concern.


    1. Thanks for your interest Kevin. Do you have a link or a quote which quantifies your suspicions regarding hydrogen leaking through air-bags or balloons, where the pressure is essentially the same inside the air-bag or balloon as outside?

      In this case of little or no pressure difference between inside and outside, the motion of gas molecules (or atoms in the case of noble gases such as helium) through the air-bag or balloon material must proceed mostly by diffusion without the assistance of a significant pressure gradient to overcome the energy barrier as the gas squeezes its way through the material.

      This case therefore is unlike the case of hydrogen stored or transported in a container at a much high pressure inside the storage tank or transport pipe than outside.

      I’d get that sorted out before abandoning hydrogen and wandering off in an ammonia direction if I were you.


      1. I actually have a patent pending on this idea from 2014. In the patent application there is also a description on how to produce the bags, so that pure hydrogen will not diffuse threw the walls, by a completely new cheap concept.
        If you are interested, then you are welcome to contact me back.


        1. Put up experimental data of H2 leaking out of divers air bags or shut up Harry.
          You can’t teach me anything about molecular diffusion I didn’t know 36 years ago.
          So you can stick your link to “Molecular diffusion” back in your Physics 101 folder.
          Don’t patronise me on my own science blog unless you want a robust reply!


          1. Is this a scientist replying to a good( I hope?) question?
            I was not patronizing you( didn’t want to do that), I still fear you are underestimating the diffusion process. When you have 36 years of experience here, why don’t you react with substance….
            Where is your robust reply?


            1. Asking if I am a scientist is offensive and trolling Harry so don’t make such offensive remarks again without an expectation that any more of such comments would be deleted without reply.

              I have neither underestimated nor overestimated the rate of H2 loss by diffusion through a divers’ air bag – because I have given no numerical estimate of that whatsoever.

              I am suggesting that what is relevant and of interest would be reports of practical experience or suitable experiments with H2-filled diver’s air bag or something very similar upon which estimates may be founded.

              What is not worthwhile and what I am rapidly running out of patience with is what Kevin and you have done which is to dare to post here about your unwelcome, idle, fatuous, tiresome and worthless “suspicions” or “fears”.

              I have understood the diffusion process for 36 years but not once in those 36 years have I filled a diver’s air-bag with hydrogen and measured the rate of losses and neither have I stumbled upon quantitative data about H2 losses in diver’s air-bags on-line. But there again I wasn’t expecting to, because why on Earth would someone fill a divers’ air-bag with hydrogen before now?

              My point was that you are impudently addressing me as if I didn’t understand the physics of the diffusion process and I will not put up with that sort of cheek in comments on my blog.

              So I suggest that you or Kevin or anyone else who has an itch to post such worthless posts again must resist the temptation, go away and do something useful instead – such as do a literature search and see if you can find something published about someone with experience or experimental data on H2 losses with diver’s air bags or similar – and post a link to that.
              Or, go away and do experiments yourself, publish the results here in a comment – or publish them elsewhere and post a link to your results in a comment here.
              Do something useful and I will thank you Harry. However, your posts here so far are repetitive and just irritating me so SHUT UP about your fears because I’ve had enough.


              1. It might well be you have enough of my good question….
                But the problem stays the same : the H2 will disappear unless the problem of diffusion is solved.
                I didn’t want to troll you, I only say nasty or inconvenient as it is, that it is very very difficult to hold H2 were you want to stay it….


                1. The point SS is making regardless of the spat between you two is that the purpose of the bog is to propose concepts and solutions and not just negativities.

                  There are a number of patents out there for ionically charged polymeric membranes that overcome this problem. Secondly the whole notion of storage of H2 is now being addressed by metal organic frameworks (MOFs). Some searching will reveal where the science is headed. The concept of taking electricity to the pressure zone rather than compression facilities is a good one however electrolysis is too poor in efficency for H2 production as the energy required in is not much more than the energy value of the produced H2. Alternate processes are possible and currently under development.


                  1. I Porter, now you too claim there’s “this problem”, which requires to be “overcome”.

                    Oh really? Well where’s the evidence for that, which quantifies the loss rate of hydrogen gas from a divers’ gas-bag? I’ve not seen any. Harry didn’t provide any. You’ve not provided any. So my challenge you is the same – put up evidence or shut up about this point, though please make other relevant points if you wish.

                    Regarding your “out there” concept for storing H2, please do not discuss such here because such is OFF TOPIC in reply comments to my blog post which is about only deep-sea hydrogen storage.

                    My concept of “taking electricity to the pressure zone” as you put it, is indeed a good one but your comment about “electrolysis is too poor in efficiency” is perversely followed up because “energy required in is not much more than the energy value of the produced H2” actually defines an energy efficient way of producing H2.

                    Rather it is when the energy required in IS VERY MUCH MORE then the energy value of the produced H2 that poor efficiency is obtained. So you don’t seem to understand what you are posting about.


                2. Harry, for the third and final time you have presented no evidence whatsoever suggesting that the rate that “H2 will disappear” from a divers’ gas-bag, would be measurable or significant in practice.

                  You’ve presented no evidence whatsoever suggesting that H2 losses would prove to be a “problem, nasty, very very difficult” or “inconvenient”.

                  Rather you’ve repeated the same scare-story which Kevin made originally, now for the third time. You repetitively finding different words to rephrase the same scare-story is serving no purpose whatsoever.

                  For so long as you have no evidence to present then I want you to SHUT UP, GO AWAY and STOP ANNOYING ME!

                  Any such further post from you making the same point without presenting evidence WILL BE DELETED!


                  1. I will not be contributing any more comments to a blog of a person who can’t stand opinions or commentary on the subjects put up. The idea of a blog is to gather ideas , share experiences and state facts. Telling contributors to “Shut Up and Go away” shows poor form, ignorance and probably the incompetence of the promoter. The fact is that this is the rudest blog operator I have ever come across in a technical forum.


                    1. The idea presented here is beautiful, and with climate warming on the background we have to find solutions.
                      I do hope SS finds a way to do the necessary research, I can’t help him with that( studied Politics / have no Lab available)


                    2. The world is full of Good Ideas. It’s not only the good ideas that’s needed, it’s money too. If this arrogant So and So tries to get funding, with his attitude, the investors will run more than a mile. You don’t strut around telling people to “Shut up” and “Go away”. In the end it will be investors that will do exactly that. (Wave bye-bye)


                    3. The answer is for the government to make a political appointment of the “arrogant” scientist with the good ideas as Governor of a public-sector Green Investment Bank. I’ve offered to be appointed Governor of a GIB and I’ve suggested public investment from new money created by the central bank of –

                      • £100 billion initial capitalisation for a Scottish Green Investment Bank
                      • £1 trillion recapitalisation for the UK Green Investment Bank
                      • €5 trillion initial capitalisation for a Eurozone Green Investment Bank


                    4. Then I hope you delete my comments but more importantly your own, since you will be cactus if they find you telling participants to “shut up” or “go away”. It’s just poor form in any forum and they will anticipate negatively your behaviour to be the same in their bailiwick. Smell the coffee old chap!


                    5. absolutely correct, I agree with you. I came to this blog via the STV website where SS has posted his/her wordpress link. The blog on STV seems to have been posted in error as it is mostly about the BBC and the Queen. I followed the link out of curiosity and am now appalled at how rude SS has been to you in particular I Porter. A simple comment, not rude, not condescending, not accusatory or critical was shot down in flames with the threat of being deleted. I thought the idea of a blog with a reply option, is to encourage debate and friendly banter. Not to be offensive. The rudest blog sums it up totally. Have a Good 2016 and keep safe out there.


                    6. Slange a var John and Jenni and greetings from Perth WA downunder. Glad to hear from you with the balanced view. It’s sad that a man with some good ideas spoils his overall chances by his approach to relations with others. At least the ideas being in the public domain now may spawn into some development somewhere somehow but it will never be under the guidance or certainly not control of SS regardless of his technical acumen. Happy New Year!


                    7. Can I just point out that I previously mentioned the word “delete” or “deleted” NOT in reply to I Porter but in reply to Harry alone and I explained my reasons for having had enough of Harry’s repetitively posting the same point again and again like a stuck record, (for those old enough to remember what a “stuck record” was).

                      Kevin made the point about H2 leaking through a gas-bag wall. I demanded evidence of that which was not forthcoming. There’s nothing more to be said until there is evidence one way or another and simply parroting that point in different words is contributing nothing to the discussion except to irritate me.

                      I felt it better to explain publicly why I was ruling Harry’s point “out of order” and that my patience as blog moderator was being stretched to breaking point so that Harry would take the hint and voluntarily desist without me actually having to delete any of his posts.


                    8. Harry, you’ve just admitted to being a student of politics, not a student of physics. So maybe you should confine yourself to political blogs telling people about political fundamentals?

                      Kiwa Technology are dealing in the transport of gas at high pressure through pipes, typically 120 atmospheres inside the pipe compared to 1 atmosphere outside the pipe, with a pressure gradient across the pipe wall of maybe 119 atmospheres.

                      That’s different from a diving lifting air-bag where the pressure difference across the bag-wall would vary from

                      • * none at all, at the bottom of the gas-bag,
                      • * to the difference in water pressure between the higher water pressure at the bottom of the bag to the lower water pressure and the top of the bag, according to the difference in height at a rate of one atmosphere difference per 10 metres.

                      So for a 5 metre height difference between bottom and top of the gas-bag, the pressure difference would be 0.5 atmospheres at the top of the bag. So I don’t think there is too much of a worry about H2 diffusing across such a low pressure gradient.

                      But I tell you what Harry, why don’t you write to Kiwa Technology and ask them if they would like to venture their expert opinion about this – and I’d welcome you quoting their reply if they bother to reply to you.

                      Whilst there may be more to be found on transport of hydrogen at high pressure inside a pipe compared to a low pressure outside, I doubt that there will be more to be found on diffusion or permeation of hydrogen through walls at low pressure differences, but by all means search as much as you like and if you find something relevant then let me know.


                    9. alas, you are wrong, the pressure would be much higher( between 200 and 2000meters deep)but apart of this diffusion works also at low pressures…
                      You should first look into the concept of diffusion, and the properties of the material of your bags.

                      When the H2 escapes it will acidify the surrounding water…?
                      Since the first Report of Rome I am interested into the subject, so while not being a physicist, I have a reasonable general knowledge of this.

                      I’m not criticizing you, nor bringing only negativities. I only want to help you on something you didn’t account for (enough) up to now?

                      I added the link only in the hope that what works at high pressure would also work at lower pressure.

                      That is all, I will not bother you anymore


                    10. Harry, I am right and you are the one who is confused and wrong. I was describing the pressure DIFFERENCE between inside and outside the gas-bag, not the absolute pressure.

                      Even if the pressure at 2000 metres is 200 atmospheres, where the top of the gas-bag is, the pressure at the bottom of a 5m high gas-bag at a depth of 2005 metres would be 200.5 atmospheres and the pressure difference between top and bottom would still be 0.5 atmospheres!

                      Don’t impudently tell me to “look into the concept of diffusion” or claim I “didn’t account for” it when you are the ignoramus who knows so little about diffusion and physics yet who foolishly states that you can “help” me who knows so much more about it than you do.

                      H2 will not acidify the surrounding water, wrong again. H2 is a covalently bonded molecule and does not dissociate into H+ ions or anything else in water.

                      You have much less knowledge than you think you have, Harry. It is not reasonable for you to dare to lecture me – I find your style of comments to be tiresome and unwelcome in the extreme.

                      No, Harry, the rate of permeation is a function of pressure difference so you are wrong.

                      I sincerely hope that is all from you and that you will not bother me any more. Good-bye!


                    11. alas, the pressure difference within the bag is not relevant, what is relevant is the differential in the sac and outside. That is what is relevant : start reading….


                    12. Oh damn. You are back to bother me again, Harry. That’s bothersome, particularly after you said –

                      “That is all, I will not bother you anymore” – Harry van Trotsenburg

                      So it seems telling lies and going back on your word is another of your character flaws.

                      Don’t “alas” me Harry me, you twit.

                      I precisely said,

                      “I was describing the pressure difference BETWEEN INSIDE AND OUTSIDE THE GAS-BAG, not the absolute pressure.”

                      No-one except you mentioned the pressure difference “within the bag”.

                      There is something wrong with your comprehension of my plain English Harry.

                      I appreciate that English is not your first language and therefore it is fair enough if you are failing to understand me easily but you really should appreciate your weakness in comprehension and take more care to read and re-read something which is in English to be sure that you have understood it and not misunderstood it.

                      Don’t give me orders to “start reading..” you pompous little fool. Go away and don’t come back!


                    13. and when the H2 leaves the bag part ( at least) will be absorbed by the water. Once that happens forming of H30+ is unavoidable?


  2. Absolutely fascinating, Just found this site from the Guardian. Am currently writing a response to Hong Kong government’s consultation on electricity market. Offshore wind is a possibility perhaps unto 300 MW.
    Prashant Vaze


  3. Respect to you that you didn’t get offended by my comments about being a mad scientist which was in fact (as you probably assumed) said tongue in cheek.

    HVDC over such a distance is going to be hard to get over the line in the best of circumstances. Possibly this will change when solar efficiencies improve. I would advocate a solar thermal plant for such a project, having in built thermal inertia required to ensure capacity factor for the line is maintained to a high level. Solar PV’s low CF even in summer simply won’t cut the mustard and storage on such a scale is only adding to already sky high capex for such facilities. That’s my take on it.

    Ian P


    1. Thank you for your comments Ian.

      I expect change to the economics of supplying renewable power from distances many times further than is now possible with current engineering practice when efficiencies are made by reducing transmission losses with the development of even higher voltage transmission lines.

      Solar thermal plant is not the only way to ensure the capacity factor for a power transmission line is maintained to a high level.

      By integrating solar PV with wind turbines and energy storage, at a remote location, on land or at sea, we can design a combined electricity generating system which can always provide on demand the maximum power capacity of the transmission line.

      If that remote location is somewhere suitable near the Tropic of Capricorn, such as the Namib desert, the Atacama Desert or Australia then the power supplied from solar PV is at a maximum very high level during the northern hemisphere winter, meaning that Europe, North America, China and elsewhere in the north can rely on long-distance solar power when locally-supplied solar power is of little or no use.

      The quantity of energy which requires to be supplied overnight on demand (and therefore “the scale of storage”) is no more for solar PV than for solar thermal. The storage element of solar thermal plant has a cost too.

      Whilst research and development and prototyping of deep sea hydrogen storage is needed to prove my claim, I do believe there are good grounds for expecting that the capital expenditure required for bulk grid energy storage using deep sea hydrogen would be modest – specifically, “it’s bags of hydrogen under water, how hard can that be?”


  4. As an 83 yr old inventor, retired printing/publishing American/English/French descendant of a middle ages French King, graduate of Kenyon College ’54 in the last century, I enter your blog with interest and trepidation! To say that I live half time in Puerto Rico where we have the makings of a potential recovery from a political-economic collapse (my special field of a B.A. only in Economic Theory) is of little scientific value to your discussion.

    More to the point is my awareness of a current investment by others to use a 22C degree differential between surface water temp one mile off shore of my home and 12,000 feet deep water where a plan is about to unfold to build a way to make electricity cheaper then the AEE can make it from burning oil or natural gas imported to heat water into steam powered electrical generation for 3.5 million consumers and the vital pharmaceutical industry.

    Those who can recognize the value of storing hydrogen to be used may well appreciate the idea of high p.s.i. hydrogen being made more easily 12,000 feet down needs to be considered. Problems of bag materials and risks, if any, certainly are part of any equation that needs government approval.

    Low p.s.i. bags on land may be an alternative, if a small chemically driven compressor is inside the bag and uses some of it to make high p.s.i. output to be piped through the bag wall for use outside along with separate release of low p.s.i. for less ambitious usage.

    So, my question is more to the practical and commercial aspect, but it does recognize that my meager study of physics at Kenyon and relatively insignificant reading since in gas dynamics, etc leaves me incompetent to do more than try to learn from the questions and answers found so far in the rather spirited exchange by keenly sensitive and well trained minds about the subject’s needs for evidence of how it can work in a way apparently not done before.

    While it is clear to me that the initial plan in PR is to make energy for immediate use, the fact is that provision to store it is very important. Equally obvious to me is that the stored water system in Ludington, Michigan in the U.S. is not the answer! A gas bag in my back yard with solar output being used to make hydrogen one way or another may also need a gas bag for low p.s.i. storage in need of certification that it will not easily pollute the atmosphere, or rupture to burn straight up with intense heat and light being a concern nearby or beyond.

    I look forward to being allowed to see further exchanges and useful contributions to a technology that may be especially important to my Puertorican friends and neighbors from December till May each year


    1. Welcome to to my Scottish Scientist blog Richard!

      Puerto Rico is ideally situated to test out the concepts I have advanced in my “Off-Shore Electricity from Wind, Solar and Hydrogen Power” blog post.

      The “Atlas of Solar Power From Photo-Voltaic Panels” colours the seas around Puerto Rico orange scoring highly with 1,600 – 1,800. Additionally, the Puerto Rico Trench offers the deepest of deep sea environments to test the concept of deep-sea hydrogen storage.

      If “Off-Shore Electricity from Wind, Solar and Hydrogen Power” is going to work anywhere, it is going to work in the seas offshore from Puerto Rico.

      The economic difficulties and debt in which Puerto Rico finds itself has even made the news here in Scotland. I wish that the people of Puerto Rico get all the best advice and this article in “American Security Project” looks to be useful advice.

      “Renewable Energy in Puerto Rico: A Way Forward”

      “a 22C degree differential between surface water temp one mile off shore of my home and 12,000 feet deep water “ – Richard Tryon

      Now that may be useful. Are you familiar with the practice of “Deep Water Source Cooling“?

      I note that there has been a feasibility study in the Caribbean which concluded that seawater air conditioning “development is likely to be economically attractive”.

      In addition to cooling air, using cold seawater from the deep to cool solar photo-voltaic panels, whether on land or on a floating platform, by another 20 degrees cooler than ambient air temperature, may improve solar PV efficiency by another 10% or so.

      Hydrogen gas is notoriously explosive in air Richard and I feel you’d be a lot safer with the hydrogen gas storing your energy in the deep sea at high pressure than at low pressure in your back yard!

      Designing and prototyping the deep-sea high-pressure electrolyser is the non-trivial missing part in this concept. There maybe multiple unexpected complications which require to be worked-around – for example, how well will the semi-permeable membrane hold up in the sea or what manner of mesh protection would protect it from the various voracious life forms to be found there? Would the electrolyser and gas-bags have to be “copper-bottomed” (in some sense) or covered with life-repellent chemicals in order to survive extended periods under-sea?

      Before this design and prototyping is done, it is impossible to be definitive about all the practical and commercial implications.

      I’m also an advocate of pumped-storage hydro systems. At the time of its construction, Ludington Pumped Storage Power Plant was the largest pumped storage hydroelectric facility in the world. I am proposing in another of my Scottish Scientist blog posts to build what I think would be the new largest pumped-storage hydroelectric facility in the world in the Scottish Highlands.

      Whether pumped-storage hydro would be suitable for Puerto Rico as a more densely populated island than the Scottish Highlands is not for me to say. There may be suitable topography for PSH but the best sites for it may conflict with existing land use.

      I’m certainly happy to advise and support either option for energy storage which Puerto Rico considers, though as an independent scientist, I don’t have in-house facilities to do any of the technical development of this concept.

      Scotland has many development facilities but I don’t manage any part of the Scottish offshore energy engineering industry, though I think our industry needs my advice more than ever with falling oil prices and the drive to meet renewable energy targets.

      Thank you for bringing your experience and the uniquely appropriate Puerto Rico perspective to this discussion Richard!


  5. Regardless of how you choose to store Hydrogen it will leak away at approximately 1% per day so if you combine that fact in your initial calculations, I don’t see a problem with your concept.


    1. Mitchell, your statement is ridiculous because it suggests that hydrogen in a paper bag will leak away at the same rate as hydrogen in a heavy duty gas cylinder. Rubbish!

      If you are turning up here pretending that you know something when you don’t, you are going to be found out.

      So the challenge to you is the same as I gave to Harry, put up evidence for your ridiculous statement or shut up.


  6. I found a Dutch dissertation :, on the permeability for H2 (for rubbers).
    Although published in 1943( their might be more recent research) it gives a beautiful and simple setup ( see page 23 / 24) to measure the permeability of membranes .

    1% per day is quite a lot, when scaling up……what will be the consequences for the seawater? Acidification will appear… how much ?
    To prevent H2 passing through the bags a metal layer could be dampened on the inside of the bags…see for instance :


    1. Harry the bothersome liar,

      I see you have broken your word again and are back here to bother me once more.

      Don’t you start parroting that idiotic statement of Mitchell’s that “Regardless of how you choose to store Hydrogen it will leak away at approximately 1% per day”. Mitchell’s got no proof for his ridiculous claims and you are bang out of order repeating it here like a parrot. Don’t repeat that nonsense again.

      I have told you already that hydrogen gas does not acidify water. Yet you repeat that unscientific nonsense totally ignoring my reply. Hydrogen gas is insoluble in water and at significant densities forms bubbles. Read this –

      “Is hydrogen gas in water present as bubbles or hydrated form?”

      So the consequences for seawater for any H2 that gets in it will be bubbles of H2. Very small bubbles will float with the current. Larger bubbles will be buoyant.

      Now don’t you dare repeat that falsehood about “acidification of seawater” by hydrogen again you ignorant little man!

      I was going to thank you for posting those links but the further two non-scientific statements you made annoyed me so once again I am simply inviting you to go away and leave my blog alone!

      An ignorant, pompous fool like you, I think, is always going to be causing offence to scientists by your nasty habit of posting unscientific rubbish.

      Harry, go away. You are not welcome on this blog.


      1. The complete text costs $35. So I have to do it with the abstract.( which is free available)

        1 Will the H2 bubbles remain 0.4–0.5 μm? Bigger bubbles will be less stable?
        2Test is done in water, will the result be the same when done in Seawater at 2000m depth?
        3What happens when bubbles start rising? They become chemical more reactive? Will get into solution faster?


  7. If you are going for deep water offshore; why not put your ‘windmill’ now watermill in the ever flowing (ie: constant), well known sea currents and skip all the hydrogen production issues?
    That would leave only the long distance power transmission issue.

    Or skip the long distance power transmission issue by still producing the hydrogen/oxygen, which will want to rise to an onshore gen all by itself.


  8. Excellent.
    Love it!

    I had similar thoughts of hydrogen production by hydroelectric generation. The object being hydrogen powered motorvehicles. Pure guess, but it seems to me such production would be pretty cheap, and be lots cheaper per unit energy than petrochemicals. Hauling a large mass of batteries around seems painful to my mind – inelegant. Petrol is good in as much that it’s quick to recharge the tank, and mass decreases as energy is used. Hydrogen (or any other fluid energy source) would have these advantages, with distribution and storage being similar.
    Hydrogen diffusion. Hmm, hadn’t heard of that problem until a couple of years ago; I thought you could just stick it in a tank and Bob’s your uncle. Very low pressure storage for “petrol” stations? High pressure but with a double hull? Outer filled with nitrogen with active “scrubbing” of hydrogen from the outer back into inner. Does hydrogen scrubbing technology like that exist?

    Love your use of depth to compress the hydrogen, very elegant – to the extent that I am smiling! Very pleasing!
    Do you need both cathode and anode in proximity? What’s the electrical resistance of 200m or 2km of sea water? Would it be worthwhile keeping the cathode at the surface for ease of servicing? What sort of servicing would the electrolyte container require?



  9. Scottish Scientist,

    I have a number of points/queries.

    1. Your 3 graphs showing the density of H2 have a small disparity in them – the 3rd one showing 16g/L at 2000m, whereas the 2nd one shows just above 15g/L – I point this out as it may have an influence on your calculations.

    2. Solar panels at sea will need to be regularly cleaned to prevent salt build up from spray, otherwise a significant decrease in efficiency would be noted.

    3. Harry kept bringing up the point of Diffusion, where I think he was referring instead to Osmosis as the issue at hand, which is relevant since the bags used are most likely of a semi-permeable nature when dealing with hydrogen, unless specifically designed against such.

    Moderator deletion deleted

    4. Surely a simpler solution, if osmosis is not an issue, would be an underwater umbrella to contain said gas, with a release valve at the top connecting to a hose allowing the gas on it’s upward journey to power a turbine before collection as demand required?


  10. It would seem that solar at sea would require too much expense for support structures. Figure, say a sq km, generating 180 MW (with no access space) at the usual 20% capacity factor for an average of 36 MW. Will that justify the expense of whatever structure and processes required to keep salt water off of the panels?
    Perhaps the turbines are cheaper at sea because they would seem to have a much smaller structural footprint.
    As for storage, batteries would be best from the efficiency POV, but not yet from costs POV.
    Now you got me wondering about the possible solar support structures – because a sea of solar would solve all the problems! Keep them away from shoreline waves with strong anchors, air filed flotation tanks and cheapest possible spaceframe scaffolding.
    If used to store H2 (at lower pressures) the whole thing could probably be as a power barge, to use wind from oncoming storms to move it around (and delete costs of deep sea anchors).
    At about $35/MW, about $11 million dollars could be earned per year minus the expense for the 1 sq km floating space frame of panels. Definitely would require a virtically integrated company! (Now i have to figure how much a square meter of PV panel costs). At $0.5/watt, it should cost $90/sq meter.
    Sadly, after all this, the PV part of it alone (without support) would cost $90 million (how does solar get so low electricity prices)? Are they less than 50 cents per watt (I’m not a banker)?
    I looked up Scottish money and learned that the British pound is = to $1.22.
    Anyhow, i hope your idea works because even though not as efficient, would seem to be far cheaper than batteries. If we worked out storage to be the other 80% (from the inverse of the capacity factor of solar minus 1 for non stored use) then we would need to store up to 180 minus 36 MW for 4/5 ths of 24 hours. At the hopes of $100/kWh for advanced, long lasting batteries, that amount of storage would cost 144 * $100,000/MWh * about 20 hours – or almost 150 million dollars!


    1. Wrong math (because i didn’t use calculator).
      144 MW * 20 hours * $100,000/MWhour of battery storage = whopping $288 million.
      Of course, all the renewable energy advocates seem to have ideas around the necessity for that much storage (I’d say build a global power line grid system).


  11. Hello 🙂
    one day i was reading a magazine and read about the underwater compressed energy storage, later that day during taking a shower (ehre most ideas are born 😀 ) i though…why not anchoring these big balloons and storing hydrogen instead in a balloon with a foil lining for H2 not to escape…then taking the produced hydrogen to the top with the same pressure to drive a turbine, (no H2O icing like air storage….and better thermal performance) or even put the electrolizer underwater, then using the Hydrogen weather in Fuel cells or mixing the allowed amount with natural gas if there is a nearby grid link……I grabbed a piece of paper and assumed 35% efficiency for electrolysis and supposed that we need some energy to distill the water through RO….I thought of course someone has thought the same…it is straight forward and cheap option, so i stumbled by your blog of course 😀
    of course the round trip efficiency is still not good, but it is still a good cheap approach…so i was very impressed by your page 🙂
    more surprisingly, I live in Egypt and I kept making calculations also for my county !! I kept calculating the initial investment approximations for big PVs and Wind turbines, we have a long shore with one of the world best spots for consistent wind speeds along the red sea, and also a perfect locations for solar projects !! more than 7 peak sun hours average per year, with no extreme weather or sand conditions.

    also we have top of a mountain natural lake-like terrains more than square KM wide in many places along the Red sea which are in locations few kilometers of the HV network lines and more than 800m high and less than 1KM away from the red sea water, a pumped storage couldn’t be more affordable !!!….yet there is only 1GW of installed wind parks and PVs are few MWs, meanwhile, Egypt contracted with Russia for constructing a 4 GW Nuclear station with 30Bn USD loan !!! while we are almost defaulting on our external debits….+ extra 14GW of Combined cycle GT plants….featuring the world’s largest CCGT plant with 4.8 GW capacity…..

    these 30bn$ for the nuclear station could have been used to construct 10GW PVs and huge storage plants…
    anyways i though it maybe interesting for you 🙂


  12. WIRED: This boat will make its own fuel on a round-the-world voyage

    “We will produce hydrogen onboard from the ocean, we will clean and purify the water and then we will electrolyse it and then compress it in tank storage.”
    The Energy Observer, which sets sail from Paris in May 2017, is an ex-racing catamaran that can generate hydrogen from 130 square metres of solar panels, two wind turbines, a traction kite and two reversible electric motors.

    ENERGY OBSERVER – The first hydrogen vessel around the world

    I LOVE IT! 😀


  13. BBC: “Renewables’ deep-sea mining conundrum”.

    British scientists exploring an underwater mountain in the Atlantic Ocean have discovered a treasure trove of rare minerals.
    Their investigation of a seamount more than 500km (300 miles) from the Canary Islands has revealed a crust of “astonishingly rich” rock.
    Samples brought back to the surface contain the scarce substance tellurium in concentrations 50,000 times higher than in deposits on land.
    Tellurium is used in a type of advanced solar panel, so the discovery raises a difficult question about whether the push for renewable energy may encourage mining of the seabed.


    Forbes: The BBC And The Amazing Tellurium Find In The Atlantic

    But we normally get our tellurium from a source which is 0.5% to 2% by weight, or 5,000 to 20,000 ppm.
    Tellurium you see is a “minor metal.” That means one gained as a byproduct of extracting something else. When we make copper we end up at one stage running the not very pure copper through an electrolytic tank to make it more pure copper. What tellurium there is around ends up in the sludge on the bottom of that tank. We actually call it copper sludges too. And there’s a company out there which collects all those copper sludges and takes it off to their factory in the Philippines (at least, last time I talked to them that’s where it was) and extracts it. There’s not even any shortage of tellurium that anyone can see. The world uses perhaps 80 tonnes a year and it costs between–last year at least–$11 and $22 a pound. That’s just not the price of something in vitally short supply.

    BBC hype? A belated April fool? Probably not worth the effort of staking a claim.


  14. This is an excellent idea! Some ideas came to my mind though. Why bother with pipelines running up transporting the gas? If you catch the O2 as well, you can construct the whole facility, that means from power -> hydrogen + oxygen -> power on the seafloor. Less vulnerable and no decompression losses. Plus no NOx risks. Things you need:
    – A place as deep as possible
    – Some filters for getting sand, marine snow etc out
    – A desalinizer, like RO or NF (for making the demineralized water)
    – A stock of highly concentrated electrolyte containing a stable anion, so maybe sulfuric acid or so, so that you have good conductivity for electrolysis but prevent chlorine formation. This you’ll need a stock for as you’ll always get some bleed or pollution over time (you desalinizer won’t be perfect) and thus you’ll have to bleed some to maintain proper concentrations
    – A badass and stable electrolyser, maybe NiFe will do just fine,..
    – Storage bags, some for H2, some for O2. Indeed proper lining using some metal alloys or metal-organic complexes here may be required to avoid permeation at the higher pressures (higher activity and thus higher diffusion gradients) and specifically for the oxygen one has to be weary of embrittlement
    – A PEM fuel cell

    Then when charging you fill your bags, when discharging you slowly pump 200 bars or more pressurized O2 and H2 into your PEM (the PEM will probably have lower internal resistance already, maybe you’ll have to heat it up though) and get the electricity out. No need for surfacing gasses, everything can be done downstairs and only thing you need to reach out for it are cables.


  15. Scotland’s Floating Wind Turbines are sited in the North Sea, east of Peterhead as located on the map.

    The map also shows the site for my proposed world’s biggest ever pumped-storage hydro scheme at Strathdearn, near Inverness in the Scottish Highlands.

    Full story of Hywind Scotland – world’s first floating wind farm. (Statoil Video)

    So thank you Statoil, well done and good luck to all involved with the Hywind Scotland floating wind farm project.

    I have described methods for integrating wind farms into the electricity grid so as to provide power on demand whatever the weather.

    As you can see my Wind Generation Capacity Focus Table (for 30MW Wind power and Capacity Factor of 40%, reasonable for an offshore wind farm) recommends the usual energy storage equal to about 90% of one day’s energy generation (90% x 288 MWh) or about 260 MWh (two hundred and sixty times more than Statoil’s ridiculously small and ineffective “1MWh Batwind battery” plan)

    Linked to the Hywind Scotland project Statoil and partner Masdar will also install Batwind, a 1MWh 🙄 Lithium battery storage solution for offshore wind energy.- Irene Rummelhoff, Statoil


  16. Why not use the pessurised gasses to transport the hydrogen and /or the oxigen up a dry mountain. Combine them to release the energie and use the water for farming or hydro power.
    The later could then be used again for hydrolyses.
    I did not do any calculations as to the efficiency. Anybody up to the task?


  17. I read your comments in the FT today on Japan’s hydrogen vision, and the use of Australian brown coal with CCS. I completely agree with your views. However, my reason for writing is that I’m very enthusiastic about an Australian innovation you might know of, from Hazer Group, which should be able to obviate the need for CCS in H2 production.

    Using iron ore as a catalyst in its process, Hazer can turn natural- or bio-gas into hydrogen and high-purity graphite, with practically no CO2. Simple graphite purification can render battery-grade material. (CSIRO testing revealed that battery capacity actually increased over many charge cycles using Hazer graphite, which comprises mainly carbon nano-onions.)

    Although it’s small-scale at present, the technology has performed well at pilot plant level. However, the company is very close to signing a deal to build a demonstration plant (100t hydrogen, 375t graphite pa) at a waste water facility near Perth, Western Australia. The use of biomethane allows them to go carbon-negative, which is likely a world first.

    Every town and city has one or several wastewater plants with a source of gas that will effectively never run out. This creates a very interesting proposition for an energy-constrained country like Japan.

    In addition, blue hydrogen – CO2-neutral – is always possible. For example, Hazer features as the technology of choice in the Hiringa Energy H2 roadmap in New Zealand. Once the demo plant is complete, projects like the above will hopefully fall into place. Another fascinating potential application is in reducing the CO2-intensity of steelmaking.

    Unfortunately very few people have heard of Hazer as yet, but it’s a pretty impressive solution I think.


  18. Dear Scottish Scientist,

    You left a comment on one of my blogposts which I have only just spotted:

    Things have moved on from decarbonising electricity to replacing natural gas and petroleum for heating, transport and industrial processes. Of course, that all hinges around recommendations from the CCC and National Grid to virtually sideline nuclear and go for renewables + brown gas to start with, but eventually leading to green gas.

    I would like to refer you to a newish blogpost tackling the demand for low-carbon electricity having to rise to 4,029 TWh per year:

    And my latest blogpost indicating investment in advanced nuclear power plants will wipe out all investor interest in renewables, starting in 2030:

    Are you looking at this 4,029 TWh of low-carbon electricity demand from a renewables + storage point of view?

    You can comment on these blogposts if you feel inclined to do so.


    1. Welcome Colin, 🙂

      It’s fair enough for you reciprocally to plug your blog posts on my blog. However, I do not favour nuclear power for grid energy and so I do not invite a discussion about the merits of nuclear power for the grid in this my 100% Renewable Energy blog. I may take you up on your kind invitation to comment on your blog posts if and when I want to argue the nuclear power pros and cons.

      It is my duty to discourage you from repeating parrot-fashion or consciously promoting the unscientific and indeed fraudulent claims of the CCC, especially in respect of their outrageous green-washing of fossil fuels or their derivatives.

      In my opinion, Carbon Capture Storage and Leak, CCS-LEAK, cannot guarantee that any carbon dioxide allegedly “stored” will never leak.

      Worse, CCS-LEAK companies could boost their profits by surreptitiously leaking carbon dioxide.

      Worst of all, mass storage of carbon dioxide gas threatens an accidental, sudden and catastrophic leak of large suffocating carbon dioxide clouds, killing sea mammals such as whales and dolphins, killing the crews and passengers of boats and ships and when clouds form or drift over land, killing human populations, farm animals and wild-life.

      So I think you are mistaken to claim that anything worthy “hinges” or should “hinge” on the extremely dangerous recommendations of the CCC, other than what we scientists, engineers, environmentalists and other responsible and informed citizens, organisations and institutions must explain and insist upon in order to repudiate the CCC.

      My Wind, solar, storage and back-up system designer can just as easily calculate from an input of an electricity usage of 4,029 TWh per year (equivalent to about 11,000 GWh per day) or about 179% of UK energy use in 2014.

      So for example, the Grid Watch Demand Focus Table generated by this link

      has a row E Configuration text page as quoted.

      Peak Demand Power: 734 GW
      Daily Usage of Energy: 11000 GWh
      Wind Power Capacity: 1280 GW
      Wind Capacity Factor: 30%
      Solar Power Capacity: 1040 GW
      Solar Capacity Factor: 8.7%
      Wind : Solar energy generation ratio = 81% : 19%
      Storage Energy Capacity: 10600 GWh
      Back-up power: 294 GW

      Comments and discussion about the calculator tool per se are best posted at this link

      Comments and discussion about renewable energy heating prospects are best posted in reply to comments at this link

      Comments about the National Grid are best posted at this link

      Comments about UK climate criminals are best posted in reply to this comment


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