What do you know about this company?

They have a nice PR video: https://vimeo.com/571525481

They want to use ships, pulled by kites to produce hydrogen.

I found one paper from 2015 that analyzed this concept (see: Economic Viability of Kite-Based Wind Energy Powerships with CAES or Hydrogen Storage - ScienceDirect ). Do you know any other papers on this topic?

I would like to understand how realistic this concept is. I have not seen an answer yet to the following questions:
a. How constant is the wind on the best possible routes on the ocean?
b. what would be the average wind speed?
c. how much electrical energy could you harvest, taking the turbine efficiency of 30-40% and the friction losses of the ship into account
d. what would be realistic costs for converting electricity to hydrogen on a ship, taking into account that you need to clean the water first

I mean, the advantages of this concept are clear:

  • pretty constant energy generation, high capacity factor
  • no flying generator needed
  • energy is stored, so the fluctuations over the year do not matter

Any comments?


Un-crewed vessels of that scale flying a kite through the ocean are a wild prospect. Not impossible.
Crews (the ones I know) are expensive

Hydrogen is perhaps the least-efficient approach to energy storage commonly discussed. It is an artifact of “a little knowledge”. People congratulate themselves on remembering one of the first scientific facts they learned right after learning to read - as a kid in third grade: Water is H2O, and can be split into H2 and O2 using electricity.

But right away there are major issues:

  1. Electrolysis is only about 50% efficient. So right away you have tthrown away half the electricity you worked so hard to generate. Imagine if someone sold you a lithium ion battery for your phone and you charged it all the way up then it said “50% charged”. You’d be calling tech support!
  2. But it gets worse: Now that you’ve used up your electricity creating hydrogen, how are you going to store it? Well you have two main options in most cases:
    a) Compress it - once again you will lose perhaps half the energy contained in the hydrogen in compressing it sufficiently to carry around.
    b) cryogenic storage: You can instead use half the energy contained in the hydrogen to cool it to a liquid , then store it as long as you can as it boils off. H2 is supposedly a really bad greenhouse gas too, right? So H2 boiling off is “really bad”, right?

Either way, you are now down to about 25% of the original energy you put in.

Retrieving the energy:
There are, again, two main choices for how to get the energy back from hydrogen:

  1. Burn it in an internal combustion engine such as a turbine or piston engine to spin a generator.
  2. Use a “fuel cell” to “burn” the hydrogen
    Either option is 50% efficient at best, even less for the engine options, especially when you include the generator losses.

So now you are down to getting back, say, a mere12.5% of the energy input.

OK so now imagine you charge your phone to 100%, unplug it and see it suddenly is down to 12.5% charge. What would you do? Could you even leave the house after losing 87.5% of your “100% charge”?

If someone told you they had developed a new “improved” lithium ion battery that could return about 12.5% of the energy input, you’d have to tell them they might want to check in at the local mental health clinic and get checked out to see what is wrong with their brain, right?

Wait, let’s ask Elon Musk what he thinks of hydrogen for energy storage:
Tesla CEO Elon Musk calls hydrogen “the most dumb thing I could possibly imagine for energy storage.”

Elon has proven he can think beyond “bumper-sticker-slogan”-level reasoning.

What is afflicting many people in the face of “global-warming derangement syndrome” is called “Single Factor Analysis”.

“Single-Factor Analysis” is when people take a single fact, such as “Hydrogen can be made from water then used as fuel”, and, without considering all the OTHER facts that go along with the ONE FACT, concoct a complicated story around the SINGLE FACT, while NEGLECTING all the CONSEQUENTIAL FACTS that complete the story. They present a partial story as a complete story, when no such thing is the case at all!

So we are presented with “hydrogen cars!” and “hydrogen airplanes!” which admit they will require up to half the volumetric space in the vehicle just to store the hydrogen, to end up with perhaps 10% of the energy input. So now your airplane can carry half the passengers, to make room for all that super-low-density, ultra-inefficient fuel.

If you choose internal combustion engines to get the energy back, you’ll only get about half the power from the same size engine because hydrogen has a very low energy density compared to hydrocarbon fuels. So congratulations, your airplane will need an engine twice the size and weight, to get the same power as hydrocarbons deliver, from hydrogen fuel. Wow, with hydrogen, almost EVERY FACTOR is twice as bad! Multiply them all together and you have an energy disaster!

If you want to run hydrogen through steel pipes, or store it in steel tanks, hydrogen ruins steel by “hydrogen embrittlement”. Currently, companies like GE struggle to include even a small percentage of hydrogen in the fuel mix of a gas turbine.

ALSO: Pulling a ship by kite so a water-turbine can generate electricity involves two (2) layers of fluid-dynamic inefficiency, and one level of electromagnetic inefficiency. The kite is only going to use a fraction of the wind’s energy to tow the ship, THEN the underwater turbine is going to cut that in half (Betz coefficient), as a start. And the generator will only be about 90% efficient. So the entire process, from beginning to end, yields a less than 5% efficiency.

Average people, including politicians, voters, and investors, are unlikely to appreciate any of this. They go by slogans and bumper-sticker logic. They are thinking “100% energy return” instead of the actual “5% energy return”.

So, all-in-all, I’d say hydrogen production from ships towed by kites is a non-starter of an idea, but today, in light of global-warming derangement syndrome, where facts don’t matter, just feelings, and lines of reasoning must be reduced to a level of simplicity that can fit on a bumper-sticker, this idea could easily get funded, and turn into one more clean-energy bankruptcy, and you can then read about when the auction of the remaining assets is announced.

More likely though, there are enough sensible people around, like Elon Musk, with sufficient adult-level awareness to analyze things beyond a knee-jerk reaction to some slogan, to prevent the waste of time, energy, steel, money, and manpower that such a futile project would entail, that you will never see such a ship built and run.

Maybe for now they should just stick to trying to convince cargo shipping companies to try being pulled by a kite just as transportation, without trying to save the world twice by producing hydrogen fuel too.

Just got this email: You can waste not only your time, but your money, chasing the hydrogen derangement dream! Don’t worry, no smart people like Elon will be there to ruin it!

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Reminding AWE Community that Ali Fujino, Dave Lang (NASA, Boeing, Drachen, ret.) and Kevin Mahaffy wrote the first white paper on H2 harvested at sea by kite and shared it to Joe Faust’s original AWES Forum and Archives over a decade ago.

Ali Fujino, Dave Lang, and Kevin Mahaffy

DF copy; go to page 65-
Discourse Issue 4 (drachenkite.com)

Hydrogen is great rocket fuel and a standard welding gas, and its uses will only increase under determined and creative engineering. JAL thinks it has found a Hydrogen Killer App as part of its Kite-Fossil Hybrid Plant concept.

First Kite Energy displaces fossil fuel in legacy plants whenever the wind is blowing. When there is no wind, fossil fuel is the backup, for baseload duty. In the next engineering iteration, onsite hydrogen generation creates just enough stored capacity to further displace fossil fuel use, during no wind, using a lot of the same boiler or turbine hardware, including blended gas mixes.


We also need to apply countless industrial processes that can flexibly absorb excess wind electricity.

Well, I would like to have a scientific analysis to compare two simple sceniarios:
a. produce hydrogen using conventional wind turbines on land
b. produce hydrogen using kite ships

What needs less resources and is cheaper.

Of course it does not make sense to use hydrogen to run your car, but there are enough use cases that require hydrogen for a world without coal, for example steel production…

If you have electricity, you can smelt steel using electricity directly. To first create hydrogen using that electricity, you will have thrown away half the original energy, just as a start.
Then we have the issue of how to provide the carbon required to smelt steel, which is an alloy of iron and carbon. Hydrogen doesn’t help there either.

The idea of using hydrogen to smelt steel is typically brought up as a “Hail Mary” (desperate) response to the unwanted facts of what a poor form of energy storage hydrogen actually is. Kind of like saying “But vertical-axis turbines are better for built urban environments because they can better utilize turbulent winds”. All just more bumper-sticker-level “reasoning” based on slogans and single-factor analysis. So far, hydrogen for steelmaking is just an experimental concept, more responsive to slogan-based reasoning than to reality.

Despite electrolysis being well-understood since the early days of industrialization, hydrogen is currently produced from natural gas, since it requires the least energy.

Governor Arnold Schwarzenegger (whom I have met on the ski slopes) announced “The California Hydrogen Highway” concept in 2004. Schwarzenegger was not scientifically trained to understand the technology. He was limited to responding to what others told him - bumper-sticker slogan-based “reasoning”. Unfortunately we are all human, and even highly-trained scientists are not immune from being convinced by emotion-based reasoning, unless they really force themselves to restrict themselves to science-based thinking on emotional issues. 18 years after our bodybuilder movie-actor “governor” announced “The Hydrogen Highway”, there are nearly zero (0) hydrogen-powered vehicles on the road in California, and only a very few symbolic hydrogen fueling stations in the state, almost never used. The program is likely to be dismantled at some point.

The delusion of a future hydrogen economy has long been debunked by level-headed realists, but it is well-known that emotions often trump facts for many people, until at some point, reality cannot be denied forever, and the facts become apparent to all.

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c. charge batteries using kite ships, generate the hydrogen on land or in a central hub.

There are too many unknowns to be able to answer that a priori I think. Maybe the study you linked could give a first list of potential variables and you could update or make your own assumptions. The electricity prices and potential subsidies would also need to be updated.

This for example seems very optimistic:

Here are 2 of 12 articles that cite the study you linked:

Besides the points Doug raises, which makes hydrogen feel similar to bio fuels, there’s also things like this:

Yes that latest warning on H2 is what I was referring to. Who knew? What’s next, tying your shoes is going to end the world?
From the fields of history and sociology, one might point out how the oil and gas companies benefit from the high prices resulting from seemingly arbitrary drilling restrictions, contrived wars, etc.
I think the fields of engineering and accounting would be in order to compare the costs of producing hydrogen via kite-towed ships pulling water turbines versus today’s windfarms.
Scientifically, pulling a kite to produce electricity certainly possible. There are unlimited ways to make (or store) some power at some cost. The question is always the same with any proposed wind energy technology: would it be worth doing? The problem there is, what proposed project ever comes in within early budget predictions?
I’ve maintained from day-one that well-meaning people say “all ya gotta do is” X or Y to store wind or solar energy, and we can easily power the entire world with solar and wind alone.
They don’t seem to realize that energy storage entails:

  1. first creating the energy,
  2. then un-creating the energy,
  3. then re-creating that same energy again.
    Logically, the resulting energy should cost 3 times as much!
    And that doesn’t even take into account the inefficiencies!
    In the case of hydrogen, you lose most of the energy!
    So is this dream of hydrogen realistic at all? Or is it an ill-advised pipe dream that evaporates when you wake up from a third-grade mentality?

At least the ship has plenty of saltwater to work with, but the only land-based hydrogen project ideas I’ve seen, that could possibly make sense, are the one or two proposals targeting existing caves or mines to store the hydrogen without compressing it. That would eliminate one of the 50% losses of a hydrogen storage scenario, but the numbers still suggest a mere 25% return on energy in. Even if the numbers could be improved somewhat, you’re still looking at throwing away half the energy.
One main hurdle is the same gas turbine could only produce half the power if switching over from natural gas, since hydrogen does not have a very high energy density.

Well, this is not really true, and if it would be it would still not matter. For the following reasons:

  1. Yes, using electricity directly is much more efficient that storing it. But if you want to ride an electric car you need to store it (unless you have catenary line above the road). And, yes, the stored energy is 3 times as expensive, lets say 18 cents instead of 6 cents in normal times in Germany. But that doesn’t matter, because that would still be much cheaper than gasoline… Now, because of the draught and the war you pay 50-70 cents per kWh at a charging station… Also not a big deal, people pay it and don’t drive much less. And if you have solar panels at home you can charge much cheaper…
  2. When using hydrogen to produce electricity you have even higher costs than if you use batteries. This is true, but again it doesn’t matter, because you will do that only where batteries AND catenary lines are not feasible, e.g. smaller train connections, long distant lorries and ships.
  3. In Germany you have about 2 weeks per year neither sun nor wind. Without any electricity import you would have to store 3.8 % of the consumed energy. If this stored energy is 5 times more expensive than the directly used energy it increases the average electricity price by 15%. Again, not a big deal… Use gas motors for this to keep the investment costs low and store the heat as it is already done in my home town, Kiel.
  4. I see the main purpose of green hydrogen as input for the chemical industry. And yes, we should eat less meat, then we need less fertilizes and the higher prices don’t hurt.

So this is quite interesting. I have been thinking about similar ships myself.

First I don’t like the video. They start out by focusing on the possibility of getting rich. Then explaining that hydrogen is carbon neutral. If I was to invest on that basis with so little knowledge, I’d be sure to get ripped off. Anyways.

They seem very unconvincing to me as their concept is simplistic. I expect it will evolve in time though. The one thing they are “missing the boat” on is generating power subsea. Power should be generated at the kite directly because the drag of the hull will be huge and you need the speed to be as low as possible. The function of the hull should be just to provide resistance to downwind movement, and secondary to provide a little apparent wind. Also subsea turbines are hard to maintain. Slowing down with the turbine hurts both of these.

I also think in-transit fuelling of ships could be an interesting option.

I see this as a low tech level startup that may improve, but the task is quite daunting. They must solve AWE, subsea turbines, micro hydrogen/fuel production, automated navigation and lots more. I think each of these would warrant its own company. So this reduces the likelihood of them succeeding

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Yes I agree: This observation takes us back to first principles in wind energy.
What I have noticed as one more “symptom” of “The Professor Crackpot Syndrome” is to add unnecessary components or steps to a wind energy system. One such item that is often mentioned, is a train (like, for example, a commercial freight train), that could somehow be pulled uphill by kites, then the energy would be extracted from the train engine as it uses regenerative braking while rolling downhill back to its original location.
What is redundant or unnecessary in such a case? Of course the main feature: the train - it was unnecessary. If you have a kite pulling, it can pull a drum to spin a generator and you are back to “kite-reeling”. The train was an example of “all ya gotta do is…” thinking. As in "Hey, all ya gotta do is install a train track and bring in a train engine and a few cars full of gravel, and automate the whole thing and enjoy the free power as it all works perfectly…
What is wrong with this thinking?
It’s another example of “The only thing wrong with this idea is its main feature!” (the train).
In the case of the ship, I think the answer is the same: The ship is an unnecessary component that doesn;t help, but hurts, the total effort.
“The only thing wrong with this idea is its main feature”.

And @ ufechner7 clarified his question to target whether the ship-towing idea would work better than just using a wind turbine on land to produce hydrogen (run an electrolysis system?)

I would say Tallak’s observation leads to the probability that the land-based wind turbine would be more likely to form an economical energy solution than the ship, because it eliminates the main feature of the original example, which is unnecessary: the ship. As pointed out, such a ship would be expensive not only to build, but to maintain and operate. Even just a boat is often called “a hole in the water you pour money into”.
Therefore, if pressed for an answer, I would say the ship-towing-by-kite-to-produce-hydrogen-from-towed-water-turbines-running-onboard-electrolysis idea would be uneconomical compared to just using a land-based or even offshore “dedicated wind turbine” to produce the electricity. Once you have that electricity, if someone chooses to throw 95% of it away producing hydrogen for energy storage, so be it. And I think the difference is the result using a wind turbine would be terrible, but using the ship it would be even worse - abysmal?
If you were just shopping for components to create such a system, a wind turbine is already the most economical way to generate electricity from the wind. There is no obvious indication at this time that building a ship instead of a wind turbine, and towing it with kites, could produce electricity at a lower cost than just using a wind turbine, which is refined for the purpose of producing electricity at the lowest cost.
Maybe the people promoting this idea should try at a smaller scale first and see if they can outperform a smaller turbine. “But people won;t take us seriously unless we do it at a very large scale!!!” :slight_smile:

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Maybe the owners of this project should start really small, say putting a single line kite on a boat, then a motion-charging watch on the boat, and check if the watch will recharge from the rolling motion of the waves. This machine would work until the boat hit land, which could be very long is a sufficiently large enough body of water is used.

To be serious.

I think the idea of gathering energy on a vessel has some merit even though your pretty “dark” analysis is probably spot on stating the vessel is the unnecessary feature.

  1. Having the option to move to different windy locations could be useful. Even so, in practice I would expect one would have to travel really long distances for this to make a useful impact, the wind at sea is pretty homogenous, and these vessels will travel not much faster than a normal sailboat.

  2. Having the option to refuel ships in transit could be the “killer app”, as you may save time in the harbour, and provide relatively inexpensive fuel to a ship that does not have enough fuel capacity to to a really long run at sea, and the option would be to resort to more expensive secondary fuels or a fuelling stop ashore. In-transit fuelling/charging though does not seem to be considered here. Using uncompressed hydrogen rather than batteries may be a good option because the energy per kg mass is a lot higher allowing more energy harvesting without sinking. Some caveats for this direction of thought of course is the volume needed and explosion safety of an automated vessel filled with hydrogen [a problem possibly more difficult to solve than the rest combined].

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Hi Tallak: I guess one thing to also keep in mind, such a ship could be specially designed for only accomplishing this one task, which could potentially reduce costs, but as you point out, any such ship with a water turbine will introduce its own factor of inefficiency. It seems like this direction of thinking could even lead back toward a circle of sailing ships using underwater reverse propellers for offshore wind energy. But is THAT an economical energy solution? Virtually unlimited ways to “produce SOME power, at SOME cost”, but which, out of the unlimited number of choices, represent economical energy solutions, versus just churning the economy for ideas that “sound good” but turn out to be a poor allocation of resources?


I am not sure to agree. As shown on their schema (which is reproduced below), the subsea turbine is oversized, leading to the requirement of a slow ship speed. So the drag of the hull is a relatively small issue. The whole should be seen as a floating plant with optimal wind conditions. Adding a winch for a reel-in/out (yo-yo) system especially for the kite would be adding some elements to obtain the disadvantage of the intermittent yo-yo mode the present device has not. By the same adding generators aloft (fly-gen mode) would be useless and would lead to other disadvantages.

Although many challenges remain, this project looks promising, especially as a bridging device.

Incidentally this project can be a confirmation of what could be a wing for an AWE system: a flexible power kite.

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I’m not so sure, Pierre: One factor that jumps right out at us, is what appears to be a “double Betz coefficient”, meaning we start with whatever inefficiency the sail itself suffers, which may not follow specifically the Betz math, since the boat does not double back thru its own wake or travel path, but other inefficiencies must be at play. Then as Tallak mentioned, you do have SOME hull drag, then you have whatever Betz-type inefficiencies are involved in the water turbine.
After that, we’re still looking at the very poor numbers of hydrogen as energy storage. If both electrolysis AND compression or liquefaction takes place on the ship, it can only return a small fraction of the energy it gathered to, say, another ship as fuel. Then if that ship is going to try to burn the hydrogen in an engine, that engine must be much larger to produce the same power, given the low energy density of hydrogen. Overall, the losses seem so overwhelming, it’s hard for me to envision a successful version of such a scenario.
I think a lot of this stuff just “sounds good”, but as Elon Musk points out, at some point you have to look at the actual numbers, and they look terrible for hydrogen as energy storage, period. How you would obtain the hydrogen is almost a side issue. Seems like no matter how you slice-and-dice it, using wind to create hydrogen in the first place has pretty-much been debunked. To go on with such ideas as this would seem to be heading toward absurd, no matter how “sexy” the idea seems, to the gadget/gizmo lover in all of us! :slight_smile:

That makes sense.

But not huge drag compared to the drag of the large subsea turbine which imposes a low speed of the ship.

In my opinion, this project could lead to some uses in sea, including refueling, rather than a real technological revolution, unless it would be a step for this.

I see the above statement as typical “all-ya-gotta-do-is” flawed reasoning. Sure, nothing matters, as long as we don’t consider any other factors, such as the fact that hydrogen already has a market price, and may be a terrible use of electricity. If I say we have to build a separate power plant to keep things running for 2 weeks out of the year, it would seem that you then need a total of two (2) redundant power plants that might both cost about the same amount. I don’t think doubling the cost of a power plant to achieve an extra 2 weeks per years of power production sounds like an economic winner. Seems like it could nearly double the cost of power all year, rather than the stated 15%.

No Doug, this project intends to operate all the year, almost all days, and I don’t think what could prevent from this. We are far from a plant which would add something “running for 2 weeks out of the year”.

By generalizing from your reasoning, we should only choose the cheapest type of energy, and nothing else. But things don’t work that way. That’s why there are energy mixes that include expensive and cheaper energies.

I think you have to think in terms of availability in different places.

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Well, you think too simplistic. The investment costs of gas motors and similar devices are most of the times neglectable. What matters is the fuel price. Simple example:

So a wind turbine is nearly 90 times more expensive than the diesel generator… Why? Because it does not need any fuel…

Conclusion: The investment costs for motor/generator based backup systems are neglectable…

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