Insurability of an AWES operation while respecting the land use beneath the AWES operation?
Mitigations?
Risks?
What uses may be made safe for the land beneath an AWES installation?
This topic in similarity case mode has been under discussion for centuries as kite systems were used recreationally and scientifically. Kite festivals frequently have officers policing space beneath kite system operations. Special areas are often bordered with visible flags and the like.
If land must be sterile of use when an AWES is installed, then the land costs (rent, lease, purchase) is to be included in the cost of the AWE operation and its products/services/energy. What is an AWES’ true costs when land-use is fully respected?
Towered wind energy allows agriculture and other operations to be fairly near the towers.
It has been noted that large powered aircraft fly over populations regularly; if the planes crash into a city, then awful things result. The planes are allowed to fly over cities because risk assessments pass muster by authorities. Those aircraft are not buying, renting, or leasing the lands they fly over.
Airports are dedicated lands; they cost something; that cost is ultimately portioned to aircraft users and aircraft-service consumers.
Cellular Kite Networks, like kite festival trains and arches, aggregate large numbers of kites in close formations. Future AWES could achieve similar densities.
These are static kites that do not generate energy. They are not AWES.
This is a not supported statement.
The current AWES are crosswind systems. There are many problems such like the lack of reliability, but their major problem is the space occupied. The second major problem is the land use. The third major problem is the space use. This is so because any secondary use is difficult or not possible in a huge area compared to the produced energy. Until we understand this AWES has no chance of taking off.
Really it’s not. You’re extrapolating from current efforts. You can’t do that. I’m sure most current players are just as aware of the space use issue as you are and have given it thought and have come up with solutions that kind of work in the marketplace that they want to enter. They still can’t get a single kite to fly reliably and you want them to give priority to getting a network of kites, for example, to fly reliably? You’ve got your priorities backwards. Don’t try to run before you can sit.
Your analysis, or statement really, like you present it here is also shallow. Anyone can think of this. A much deeper and much more thorough analysis would be much more helpful.
Your comment is quite irrelevant and not supported from A to Z.
This is an unsupported statement.
Yes I can.
I have not seen a single example, apart a non AWE player on
Crosswind flight drags very strong, very thin, very long tethers at high speeds. Mast concepts expect low attachment points to avoid unnecessary forces acting on the masts. They claim this as an advantage. However, this means that the high-speed tethers are moving low to the ground near the attachment point, and failure conditions would cause the tether to sweep across the ground. This creates a high-risk situation for people working in wind farms for whatever reason. It’s unlikely that this would create conditions amenable to secondary uses of the ground between wind generators. And it’s unlikely that this would be acceptable to workers’ safety and insurance organizations, requiring temporary shutdowns of numbers of the devices in order to service a single one of them. As collateral, tether length is typically the minimum safe spacing for generation devices, as Makani recognizes, but Kitegen does not in their publicly available literature.
You are wrong from A to Z. @katieschaef’s wing and other AWES from other companies already fly more or less reliably. But any secondary use under a long tether moving fast at low elevation angle is not possible, whatever the degree of reliability of the kite, and I’m not even talking about a kite network, but only a crosswind kite with its tether.
There is no point in trying to solve common engineering problems when on arrival you are sure you do not have a viable system. Do not start building your house if you know you will not go beyond the foundations, and also I challenge you to build it under the trajectory at low elevation angle of an AWES crosswind. It is not for nothing that the Enerkite team in AWECBerlin2013 asked spectators not to be below the path of their AWES which was however small in scale.
You confuse the statement such like the last I repeat again and again with the whole analysis from the 59 Land and Space used.pdf (70.9 KB) to the bad or good solutions I envisaged and related on the forum such like Rotating Reel System, Low radius loop, Vertical trajectory for yo-yo AWES?, Power to space use ratio, not to mention the unsuitable “solutions” such as the arrangement of AWES insufficiently spaced within a farm without taking into account the changes in wind direction within the farm, and which I have repeatedly related. But you are far from having made the connection. Certainly this requires a minimum of intelligence. I advise you to read everything I have written on this subject before commenting so nonsensically.
“Anyone can think of this.” Apparently nobody. It is not for nothing that Michael Barnard notes on
It was a disappointing dive into the rabbit hole, interesting but notable mostly for how participants in the space didn’t seem to have the ability to build Level 0 requirements, understand anything about regulatory requirements for energy, understand anything about actual wind energy, understand anything about end-to-end systems thinking, or generally have their feet on the ground at all.
Michael Barnard is about you. The and use issue is a major end-to-end issue within a system thinking.
And I am unfortunately the only one to understand it. You (and the AWE community in general) can persist in your blindness for what is obvious, but however aptly pointed out by an opponent of AWE.
The only way out (if there is one) is to think of architecture as a consequence of the land use major problem.
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.
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!
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.
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.
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.
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:
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.
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.
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.
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.
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?
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…
@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.
