X-Wind Powerplants GmbH

Came over this when cheching out Uwe Ahrens new book. I think it was mentioned earlier slightly, but for me this was news.

https://x-wind.de/

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I was going to suggest a circular railroad track instead of pulling ships dragging turbines thru the water of “Oceanergy”. Impressive reading material for those who have not read a hundred previous articles acting like the subject actually even exists, and talking up all its great features in exacting detail. But alas, we long-time recipients of such promotional material know that we are reading hopeful fiction, not the purported description of an existing technology. How many times have we heard similar stories? Not saying it is a bad idea, or that it won’t work, but where is one, even a scale model?

Main advantages of the X-Wind technology:

CONSTRUCTION

[1] X-Wind Power plants consist mainly of modules of proven technologies (parafoil kites, parts of locomotives, rail system, grid connection). This minimizes the need for technical development, ensures stable supply chains with low capital expenditures, and makes it possible to involve local suppliers and partners worldwide.

[2] Enormous resource savings (90% less than conventional wind power), low dismantling costs (< 1% of the investment), All components can be renewed individually and are up to 95% recyclable.

[3] High fatigue strength of main components (power units and rails >30 years).

[4] X-Wind power plants can be placed almost in any region of the world, also in areas where the wind is too weak for conventional wind turbines.

OPERATION

[5] X-Wind kites can also be launched when there is no wind on the ground: the power unit pulls the kite up to a high enough altitude with sufficient wind energy.

[6] X-Wind power plants have a very good control capability, they can be shut down in less than 20 seconds and can take up to 50% of the installed power from the grid.

[7] In the unlikely event of total technical failure, the parafoil kite (which is made of soft fabric) would gently and slowly sink to the ground.

[8] X-Wind power plants are safe for aviation. They are outfitted with an automatic collision avoidance system.

My take:

[4] Anywhere in the world with a large flat area and space to place a large rail. Most probably the area inside the rail can’t be used, unless you also build some tunnels to allow traffic. If the area is not already flat, it must be made flat, but only minor adjustment to flatness could be made, as a windmill could not be placed underground effectively. From my oerspective land use is particularily large in this one.

[5] I like this one a lot. But still unanswered is how you would arrange the lines and kite in order to get from grounded to flying the kite. Its not straightforward, and I suppose X-Wind has some ideas about how this could be done. So for me sitting on the fence on this.

[6] is a good point though still I expect normal windmills are superior in this respect. Also I expect the wagons will not move at constant speed around the track with constant power generation (*) so power output is initially variable. This would be equally negative to the initial proposition, just showing that this is a brochure and not a neutral discussion of the design

[7] Not the case in medium+ winds

[8] Really? Where can I see this in action?

(*) Actually constant speed could be achieved if the wagons were connected by tethers so that their distance was fixed. Then power output would indeed be close to constant. But that makes the optimization of travelling faster past less attractive parts of the circular rail impossible. Those parts being where the track is aligned in a way that wagons move upwind.

All in all, an interesting design that seems easier to build.

The practical ramifications of the large ring track scares me. For sure this design would not see much use in all of Norway due to the steepness of the terrain. Nice flat terrain is usually farmland or desert and I doubt one would sacrifice farmland for windmills. Desert cones with its own problems but seems to me
being the most likely area for this.

I am also a bit worried about transferring energy from the wagons to the circular track. One thing would be the «slipring» that I don’t think would last the advertised 30 years. The other thing is I believe rail tracks have a gap between them to allow some length increase in hot weather. So maybe a standard railroad track could not actually be used?

I don’t think the track needs to be circular.

If it doesn’t you could imagine running it between cities or destinations and also allowing other trains to run on it during peak hours.

If you could remove overhead lines from (disused) regular train tracks and instead use some other method to transfer electricity to and from trains and this concept train, that would be good. If you had a single track rail, perhaps you could use passing loops to allow other trains to pass, allowing you to use \frac{1}{\pi} length of track compared to using a circle.

I guess it could work anywhere where regular rail also mostly works. I think you’d need to know the efficiency of regen to know at what inclinations it stops making sense.

In trains that is done using overhead lines. I don’t see why something like that, but not directly overhead, couldn’t be done here.

I don’t know if there is more testing that was done beyond this, some while ago: https://www.youtube.com/@X-windDe/videos you would think the train and kite would need some development that you could do before you built or modified more than a short train track.

Perhaps there are still some regions where train tracks don’t have overhead lines, you could test your system there (now with battery storage).

The US railway system is not electrified and Europe is still only at 60 percent it seems:

You can make your own train track map across the US say and schedule your trains according to the weather forecast. You’d need to add a discharging station at every stop.

ChatGPT on how to get a new concept and trains on the US rail network: Slow Chat - #783 by Windy_Skies

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True, but it should be aligned with the prevailing wind directions at the very least. And I believe the wagons should move very fast, maybe 40-50 m/s so that would put severe restrictions on which tracks to use.

And it you travel far, the wind resource will vary a lot. Again maybe not if you are crossing a desert

I am not sure about this. 40-50 m/s can be the speed of the kites as they fly crosswind by figure-eight as shown on the website. Perhaps the speed of the wagons could be something like about 15 m/s, maybe even less.

I recall a piece of information about the speed of the KiteGen carousel which is also much lower than the speed of the kites (see the document below on the next comment), a bit (but not quite) like the speed of the tether during the reel-out phase for yo-yo systems, also compared to the speed of the crosswind kites.

In general I’m not sure that such huge infrastructures lead to economically viable solutions.

Document from KiteGen:

From page 14/27:

how much energy can be generated ?
ƒ The turbine rotates at 0.16 rpm, with tangential speed of 5 m/s (18 km/h)
ƒ Simulation of a single KSU
ƒ kite area A= 100 m²
ƒ kite efficiency E= 8
ƒ wind speed We= 12 m/s
ƒ turbine radius R= 300 m
ƒ The kite flies “lying eight” at high speed (around 200 km/h)

I was explaining this and the Oceanergy concept to a wind energy manufacturer friend yesterday. Regarding Oceanergy, his comment was: “How many layers of inefficiency do they want to combine?”
Regarding the railroad track idea, seems to me we’ve been discussing this for well over a decade, including many “carousel” concepts, and of course using existing railroad lines. More “All ya gotta do is…” hypothesizing. OK, rather than building an inefficient ship With water turbines to drag thru the ocean, with Onboard energy storage (“all ya gotta do is!”), electrolysis, hydrogen storage, etc, etc, etc, at least a railroad Engine has less drag than a ship, but why is there none of these running anywhere? And if a kite was powerful enough to pull a train engine (Extracting power instead of using power), could the kite cause a derailment? Then of course you have to store the energy on maybe another car or two? Whereas a wind turbine can be connected to the grid. “We were going to build a wind turbine, until we realized how much easier it would be to build a railroad!”

@dougselsam
There alway a third rail transfer?
If you want to go the kite route?
There also rail type to consider if derailment concerns you?
Reading a circular track? Well are kite want there own particle accelerators? Truth be known it not to hard to make a oversize generator this way? You technically could build on with x dia. Powered by multiple kites? Only needing the outside radius? Simple t section track should do? It would be hard for it to derail if attracted to the underside of the t beam or I beam? Think rollercoaster operations? Depending design direction?
The track could be built like aertotrain? Reverse maglev so to speak? There is no end to scale there? Though cost per mile/km might be quite expensive? GW maybe TW? If built as a trans global generator? How big to do like Awes?
image
Swept area is important right?
There has been a question of how to power the world? Something that obits it might just do the trick?
Anyone else want to join in?
Or wish to add something?

How heavy is one section of rail?
Can you build a ground station with the same mass instead? If so, just do that.

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@Rodread
There are many ways to go about track

https://www.lighthouseaudiovisual.co.uk/alustage-tuv-f34-pl-al34-lighting-truss-straights-128137-p.asp?_=&variantid=128138&gclid=EAIaIQobChMIg7qmq4fg_QIVA-ztCh3AvQeGEAQYAiABEgLgXvD_BwE

There also Aluminium extrusions? That can prevent derailment? Sort of like a curtain roller system?
Power to materials ratio? Materials used vs expected output = cost of manufacturing/cost per kw?

It would be ideal in a disaster emergency situation for quick development?

Sure the more permanent structure would use more than materials than a basic ground station but really it durability we are looking at here? As that will effect running cost?

It don’t need to be heavy at all?
I had a vision of kites in a dream once powering a section of railway up the Avon causeway years ago? On the old Christchurch to ringwood branch? Never quite understood what that meant? With help it could come into sharp focus?

I’ve two pictures in my mind one is like windswept? The other it’s a kite pulled sled? With multiple units on a looping track?
Built much like film cartridges shape? With minimal passing distance accounted for? In that dream it also powered parts of Christchurch? So it must of been pretty bulky to get the council in on it?

Currently in my area

So do the math and it alot for the year? Considering there about abt. 1/2 million people Living across the conurbation. per head it’s a lot of energy consumption? Abt. 130,000 in Christchurch? Datums to how much energy it would have provided the town?

So that was abt. 2014-2015 when I had that dream?

Some variety of this might do it?
If someone willing to crunch the numbers?
It can be a possibility? It wouldn’t take all that much?
Heck it might just fit a ground station as well?

Just depends how you wish to generate electricity?

That would make it nonviable. What’s the difference in available power between this and what Pierre is quoting?

Another idea, add grooves in or on the sides of roads for your train wheels to ride in. Or initially accept the higher rolling resistance of wheels on roads.

It’s a funny problem. Now you have to develop an autonomous road safe vehicle, with height restrictions with kites that perhaps also need to quickly launch and land to go under traffic lights and overpasses.


Or, inspired by this: Meet the 89-Year Old Who Built a Train in His Backyard | WIRED - YouTube a series of posts with the top of the posts bifurcating into two (to support one line) or three or more (to support more lines). You would connect the tops of the bifurcations together and string a line between the posts, through the bifurcations. Then you would make a carriage in two parts that sits around the line, the bottom connected to the top magnetically, like in the video. (Or just make the posts T-shaped like those for ski lifts are, and also use something similar for the carriages as ski lifts use.) Each vehicle would have several of these carriages to increase grip, allow for momentary disengagement of one of the carriages, and increase stability front-to-back. You could use two lines per vehicle to also increase stability side-to-side. These posts can be short and the lines could perhaps lay on the ground when not pulled on by the vehicle.
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@PierreB @Windy_Skies @tallakt @Rodread


Or?
image
But the other way up? These systems already exist it. Just a question to how they can be adapted for kites?

A yo yo system might pull the kite in for just long enough? Sensors on the train and track could trigger it? Also warn of complex section where there a serious risk of entanglement with structure?
Complementary system might be required on the tricky section

Or alternatively
image?
Enter the sail train.

At 0:43, we see that the wagon goes slowly while the crosswind kite flies fast. In a similar way the reel-out rope speed is (theoretically) 1/3 wind speed, so far lower than the speed of the crosswind kite. It’s a classic case of high torque by low speed.

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Thats ok. I realize they are probably still in the early phase, but to normal people that video was rather unimpressive. Cross fingers things look more powerful soon

That doesn’t address the point though. That video was an illustration of the path that we assume the company, or person as I only saw one person on the about page, wants to pursue; a carriage moving downwind with kites moving crosswind. To answer a question similar to my own from before, if I’m correct for that you’d need 9/4 more kite area than if you wanted to have the carriage moving crosswind, which sounds achievable.

The alternative, something like a high-speed rail that can take significant side-load, x times longer than the alternative, with no obstacles on either side, doesn’t exist today for one, and would need both decades and infinite money to build. So I’m doubtful that is the better solution for now. Unless perhaps this high-speed rail isn’t so difficult to build after all or actually already exists.

Wing sails could also come in handy here? Much like the solid sails on ships


Should adapt for railways easy enough? Telescopic mast option as well?
Might be possible to use a version of the India rope trick? For rapidly development and obstacles avoidance?
That’s another direction to be investigated?

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Yes. But that plan of moving downwind is not so good I think as power delivery of the kite will be very unsmooth, as we can also see on the video. So maybe you could move the kite slightly to remove some wagon speed but I think it still needs to move slightly fast.

Also the rail must hold side forces as the carts still need to move crosswind and upwind.

I would also like to mention that besides the book release, much of the stuff from this company seems a bit old.

The problem with side forces can probably be alleviated by tilting the track inwards towards the center. But I would think a railroad track is anyways capable of withstanding lots of side force.

I dont think building the track is the biggest problem here though.

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But where the traction is stronger, as indicated by Beyond the sea, different flight modes. And moving downwind (for the tether during reel-out phase) is naturally used in yo-yo systems, the kite flying crosswind by figure-eight in the middle of the flight window, so in the more powerful zone.

This is where we see that alternative devices to the yo-yo system lead to structures that are unnecessarily heavy and even less adaptable to the parasitic forces generated by the figure-eight movements of the kite. The yo-yo kite station can pivot during the kite’s movements so that it remains in line with the tension produced by the kite, which a rigid track cannot do.