Land Use Under AWES Operations

No, it just looks at the problem from a different perspective.

Is that your analysis? It’s a one page document.

This is an unsubstantiated statement, and diagram. It is useful as a starting point to think of solutions to improve on this worst possible configuration. But even this worst possible configuration is fine in a first, or n-th, iteration.

You should try to read carefully before posting irrelevant comments. So I put the extract again:

And also an empiric observation I repeat below:

It is clear that the “one page document” is a part of my analysis.

IIRC only this link has much discussion on this question, where arguments for and against your position are given.

That is one possible solution. Just like birds moving in a swarm, kites should be perfectly capable of avoiding each other, eventually, after the n-th iteration, if that should prove necessary. Or you could try to prove that they will never be able to.

You’re trying to prove a negative. By giving a solution that could work eventually, among several, I think I have weakened your position.

If you’re invested in this and you would like to convince people, you could try to dive deeper into the difficulties. You could collect and visualize data on wind shear for example.

What absolute nonsense! They exist, period. From where AWES insufficiently spaced within a farm…

With your birds!!! I inform you that the birds are not tethered. Moreover I related (also) the case of only one crosswind kite with only one tether as I repeat again and again:

There is no deal possible with this. There is no “solutions to improve on this worst possible configuration”.

Will it be better with larger wings ?! Just as you cannot build your house in a nuclear power plant, you will not be able to build it in the area of ​​an AWES, nor will you even be able to cultivate under fast moving kilometer ropes.

The only way to reason correctly is to consider how much power can be extracted in a given volume or surface, as for any energy system, considering that unlike conventional wind turbines, secondary use is difficult or not possible. So the space must be maximized in order to mitigate this problem.
And I do not see the beginning of a concern for this problem which is wrongly denied, by simple blindness.

I largely did it, document, topics in support, and empirical observation about Enerkite demo in Berlin2013. I would add the required spacing for small piloted kites unlike large static kites in festivals such like Dieppe. Now maybe you prefer Michael Barnard to let you know when the AWES drops out and investment hopes can only diminish …

Some AWES may be installed for seasonal uni-directional winds.
Or installed for limited day service for unidirectional winds.
The air space is not rented, leased, or purchased. Other aircraft will use their own air spaces.
May we not look forward to such good risk assessments where projective land space is not owned by the AWES operations? And look to secondary use of the land area above ground and below ground. And look to staggered operations for harvesting/downAWES-time?

Land space concerns and airspace concerns related to energy kite systems have been present for millenia. Pilots and systems needed land and sea for launching and landing. Large systems needed more operational room. Wings had to be handled, arranged, set in place, stored. Teams of kite system operators knew that their wings and lines needed safe room for operation.

Parallel use of land: Specially designed harvesting machines and plowing machines could be used during energy-kite operations; even robotic harvesting machines. Grow fuel crops. Farm fish. Grow construction wood. Salt evaporation ponds?

The “fall-land area” is much larger than the disk of radius of length of the energy-kite system (AWES). Why? Breakaway wing sets with tethers could fall/drag for tens of kilometers and more; if the dragging tether set does not snag enough but provides enough drag for flight to continue, then a rogue system could cross a nation causing havoc again and again and again …before final stoppage. A powered jet airliner could take out many buildings and hundred of people upon a crash. But a huge runaway AWES dragging lines across roadways, structions, homes, building, could cause highway wrecks, start fires after fires, cut out power lines in town after town after town, … My bet: We are not going to rent or buy all that land. AWES will need to be certified to lower risks, so that AWES may join other aerial users without having to buy all land flown over.

With wind and weather watch, powered aircraft will be able to communicate with AWES, so that much of the domed cylinder of potential operation could be flown through at any particular time. Things are getting smarter and smarter up there!

It is the reason why I added a fall zone.
Space and land use with different elevation angles and crash zone

And this is yet a very optimistic first assessment. You rightly mention:“The “fall-land area” is much larger than the disk of radius of length of the energy-kite system (AWES). Why? Breakaway wing sets with tethers could fall/drag for tens of kilometers and more”.

But most of all the area of ​​3000 meters x 1000 meters height that was granted by the Norwegian CAA to Kitemill is irrefutable proof of the land and space use problem and confirms what I am telling for years. The Norwegian CAA unterstands it but not AWE players. And the issue is similar whether for the no-fly zone, and the land area. It’s obvious.

I think it is not possible due to the tethers, particularly for crosswind AWES. It would perhaps be possible for small static AWES flying at a high elevation angle. So It must be admitted that a reserved space is essential, and therefore think of maximizing it, using the Power to space use ratio instead of the power/kite area ratio.

You need two pieces of information to be able to analyze the risk, for yoyo systems say: current and historic (1) wind shear and the ability of your system to (2) stay within their respective cones, even with wind shear.

We don’t know (1) and (2) is unknowable even for current employees at a company for future products, let alone outsiders.

We do know that (2) is probably absent for small static systems so you’d have to rely on more distance and smaller wind shear for those systems and you perhaps won’t be able to control their landing as accurately when they fail.

Someone interested in this problem could try to get accurate data on wind shear for a site and the size of the cones for different present and future systems and based on that information try to work out the spacing needed to limit landing due to wind shear below different percentages.

They could also try to work out solutions for when a system does fail, because [b]reakaway wing sets with tethers could fall/drag for tens of kilometers and more is a worst case scenario that could be eliminated just by detaching the tether from the kite for example. If you want that’s a case against using fabric kites as well.

I fully disagree again.

The first safety measure would be to move the secondary use areas away from the place of energy extraction. The total area covered by AWES and comprising the tethers is a minimum. And I don’t think regulatory requirement authorities rules would do it on a case-by-case basis. Be realistic a minimum.

Crosswind AWES faces hazards of many sorts (mechanic, computer failures, weather…) for one rigid or even soft kite moving fast with its long tether. As a consequence dealing with these risks is not possible.

Things become yet worse if a kite-farm is implemented, due to wind shear added to other risks, requiring far more spacing that spacing sketched in publications in which the authors confuse the natural wind with a wind tunnel.

For small static systems the consequences would be lesser. A 100 watt static AWES flying at a high elevation angle of 60° is infinitely less dangerous than a crosswind kite of only 2000 W at the end of its highly tensioned 300 m rope and flying at high speed at a low angle of elevation of about 30°.

As a result the AWES area should be reserved and exclusive (no inhabitant, no secondary use as for an airport) for all crosswind kites, alone or within a farm, rigid or flexible. The only solution is to maximize the area so that the energy produced compensates for the blockage.

For another risk such like wing sets with tethers dragging for tens kilometers, thus largely leaving the reserved and exclusive area, it is another concern linked to the conception (and not only an uncertain tinkering in order to detach “the tether from the kite”) of the AWES.

An example of a land use management is below (from Power to space use ratio),

Figure 4, from V. Salma, F. Friedl, R. Schmehl: “Improving Reliability and Safety of Airborne Wind Energy Systems”. Wind Energy, in production, 2019. doi:10.1002/we.2433 . Preprint accessible as pdf :

IMHO the Danger zone should cover all the ground zone as a minimum, likely more. The kites should be spaced more, by at least a tether length, in order to mitigate unforeseen events such as wind shears.

Then some strategies allowing to maximize more the space occupied should be studied in order to increase the frontal airspace swept by the kite(s), such like Low radius loop or Vertical trajectory for yo-yo AWES? to stay in neighboring architectures. Other architectures like @Rodread’s Daisy network seem to have the potential to respond favorably to this major security and credibility issue and which is quantifiable by the Power to space use ratio.

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Sure. But like I say because they probably have nil capability to deal with wind shear they’ll probably need to be spaced further apart if you want to maximize uptime and if you’ve determined wind shear is a problem at your site. They’re also largely irrelevant.

Unless you describe these risks better in your quantitative analysis a response to your concerns is not possible. You point out a potential problem, you don’t analyze the problem, you give an unimaginative solution to the problem, and then claim because your unimaginative solution probably won’t work dealing with these risks is not possible. That’s the exact wrong way to deal with any problem. That you can’t imagine a solution to a problem doesn’t mean that no one else can either.

You’re using the exact wrong framework to try to understand the issue. This one is better for example:

If you need to be right before you move, you will never win. Perfection is the enemy of the good… Speed trumps perfection…

In new product development or start-up culture the above sentiment is translated to fail fast, or more accurately iterate fast.

I addressed that.

It is only your opinion. My arguments are reasoned and set out above. If you want to refute them, take the trouble to expose them one by one with your rebuttal. I am waiting to see.

Describe what you call my “unimaginative solution to the problem”, by inserting not truncated quotes. For the moment I see nothing but unsupported opinions.

Quote the not truncated passage.

It is only your opinion. I related several times some solutions. Refer to them.

I don’t care. These are generalities, not more.

You do not understand that AWE is not just a start-up.

No, the initial sentence is from @JoeFaust:

Then you put this:

Then I put it again but within some context you ignored by truncating the passage:

To resume you should indicate what is the problem I evoked, then my “unimaginative solution”, supporting your opinion by not truncated quotes.

I let my kids play underneath my kite turbines, but even they aren’t stupid enough to go under a fast & powered up, rigid blade, kite turbine.
There will be no other land use permitted under early model AWES used for permanent utility.

Let’s clarify about kite networks in this thread.
Kite networks undoubtedly make kite operations safer. Have no delusions here.
Kite networks stabilise kite motion by using wide tethering to limit the available flight path. That is a thing.
Kite networks enable redundant safety and control via back-lines, side-lines and multiple tethers.
Breakage of an airborne component in a kite network almost always depletes the capacity of the kite network to perform high energy aerobatics.

This is what I have used previously used to ask event organisers for as an excluision for running a kite turbine. On it’s own in a field it would require a 28m radius

That covers a good start toward safety improvement. I should think you all agree. I’m very keen to hear comments.

Next onto density of energy production 28m radius as mentioned above is a lot for a small 1.5kW turbine demonstration. This is early days. This is a parametrically reconfigurable network turbine.
It’s going to improve.


Not sure I’ve meant to imply that one day I will be like a horses arse…?
But improvement is coming for sure.

I’d agree that in this following pretty rendering the kite turbines are shown too vertical and close.


But here we can see an idea of a ground area covered in a volume of kite generation.

Before anyone says, … Yes, this is designed to take wind from any direction.
Is the lifting network optimised yet? no.
Is the turbine design optimised yet? no.
Has prototype performance smashed the other designs out of the park? yes.
Should it have because it’s small and therefore has relatively more drag? no.
Holy F, How many teams report working on this type? Only 3.

Will it actually scale?
Well a few tests here seem to say yes. Scaling by stacking works. I have also flown kite turbines with more drive kites per ring. Better demo coming soon.

To recap on a couple of scaling threads…


These sim sets show multiple Tensile Rotary Power Transfer rig designs work even on purely soft TRPT net designs given a good range of driving kite dynamics which inflate, lift and rotate the rig.

More on that here.

Concluding this post (at last and back to work) Adding to what I said at the start
There will be no other land use permitted under early model AWES used for permanent utility, if that’s how you develop your system.
It’s how you play with as you develop your system that counts.
See Myrons latest Maxim again…
The process you use to get to the future is the future you get.

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Rod, the land use management looks to be reasonable. And also your system is potentially more suitable in regard to the land use issue for many reasons such like redundancy of constrained tethers in rotating columns of low radius, small elements in flight, and above all a far better potential of Power to space use ratio.

The network will work well when winds lead it in expansion. Problems can occur when winds will lead it in contraction. For these problems I would suggest to think about the AWES farm in bumper car mode concept. Why not using some lifter kites (for example some unities of the Sharp rotor that is stiff enough) as separators?

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I particularly like your suggestion of Bumper car mode @PierreB
In order to make multiple rotary tower kite turbines compatible with collisions, their configuration needs to change so that the driving wings do not protrude outwards from the torque net.
The Djembe OM kite is a Dasiy type designed along those lines…


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@Rodread I think the Bumper car mode could concern the upper layer with lifter kites. Both ground anchoring spacing and upper layer(s) spacing might be enough, the collision zones being only in the upper layers.

Implementing rigid elements such like inflatable or semi-rigid kites in each of the stitches would not be necessarily required.

It would suffice to place some of these elements in various orientations in order to allow the approximation until the collision included of the elements of the upper layer without the turbines colliding.

That said what you indicated above and I quote below looks to be a workable solution for turbines colliding. Thus the full Daisy network could work in Bumper car mode. It would be yet better.

Now a related question will be the securing of the superimposed rotors. The Bumper car mode could be not suitable even if some elements could add also some torque transfer.

I rather think about an accordion configuration, implementing retractable tethers.

Prof Hironori Fuji has previously investigated automated rotary deployment and retraction for antennae in space. I believe he is considering how it may be used on Daisy turbine TRPT’s.

kFarm started as a private airfield and hay farm that became an AWES R&D site for three years. It was shown that commercial hay-farming, cattle-grazing, kites, and aircraft easily co-exist. Integrating kites with general aviation is simply a matter of shared land and airspace, by coordinated operations. Several other AWES programs have validated similar spatial co-operations. Advancing airspace automation will support ever more complex airspace usage.

Land is not used intensively in many remote and rural parts, such as where I live.
Alternative land use wasn’t always a top priority for me …
However, everyone has food sustainability considerations at the moment.

In order to maintain layers of AWES and farming, there needs to be physical protection of the delicate biological and delicate kite materials.

The best way to grow food reliably here in our harsh, windy and cool conditions is inside a polycrub.


At 2m tall there’s not a lot of clearance to worry about. There have been some fairly large arrays of them. The convex polycarbonate shell offers good protection to workers inside. As a bonus the frame is made from recycled fish farm pipes, of which I have removed ~100m from local shores.

Depending on the compliance of your kite device, it could be landed on, bent over and attached onto these shells. Kite rings are pliant when not being flown.

1 more thought. Not strictly land use… Tensile kite lattice frameworks were proposed as an enabler of vertical farming support. Personally I’m concerned the wet mass implications of such design concepts would be a show stopper.

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It can be a possibility in some cases. AWES designers, and farmers, could agree on the compatible sorts of AWES and farming.

That said knowing that “A Polycrub is a permanent structure”, the “build typically takes around 50 — 100 hours, depending on size, ground conditions and any internal fit-out”, I would be curious about the price of its implementation on a whole land area of a basic AWES (about 1 km² by taking account of the wind rose). We will likely not see poly tunnels under AWES for a long time…

Polytunnels are a great idea under giant soft kites. Underground concrete bunkers had been suggested in the past for operations under high-mass high-velocity AWES [Old Forum, Feb 9, 2010].

The tunnel form is not only apt to not snag active kites, but could comprise special kite support structures to store and dry kites (solar and/or forced-air), as a giant “spinnaker-sock”, or a long gallery suited to lay out line rigging, or even assemble giant kites on-site. Polytunnels could protect vehicle and pedestrian traffic across a kite field.

The Shetland Polycrub is a particularly outstanding wind-resistant design, based on poly-tube reuse. It could be a ready basis for scaling up Inuit Windsled design. Such structure is inherently lightweight, and could even evolve into airborne service, as an Aerotecture design option.

Commercial pilots sometimes joke, “I work in aluminum tubing”. An AWES pilot might someday be said to work in poly-tubing.