Just had a video spoon-fed to me by youtube, called “The Laddermill Explained”

Rather than showing a laddermill, it instead shows a “yo-yo” kite-reeling rendering.
The video is dated 2010 - the time when the “laddermill” concept was being promoted, but it was easier to fly a kite than to build a laddermill, so they continued to use the name “laddermill”, but tried yo-yo kitereeling instead. I think they finally stopped calling it “laddermill” after some time went by.
I always thought the yo-you kitereeling looked questionable, but what weight does my opinion have in the company of so many highly-degreed engineers etc.?
So, since 2010, I’ve been hearing about the incredible amounts of power (such as “500 kW”) these yo-yo kitereeling systems were supposedly capable of. My take at that point was that, regardless of the efficiency, these people must be having better luck than I had theorized. But now, nine (9) years later, where is one yo-yo kite-reeling system in daily operation? We’ve certainly heard enough promises and press-releases. Now, rather than endless press-releases, we’re in an information drought. All we really know is that things are not panning out as promised. It would be great to have any real information to sink our collective teeth into, but I don’t know of any. Maybe someone associated with any of these projects will “leak” some information. But just saying that pretty much tells you all you need to know - not much happening with current AWE projects.
Remember “The Wizard of Oz” - whether its a piece of paper saying someone “has a brain”, or a little heart-shaped memento to wear over your chest, “Pay no attention to the man behind the curtain”.

There are some bits.

Was there a pivot somewhere already? Those are the original AWES concepts from the 1970’s … I for one am really looking for progress on those designs now. Why aren’t they more successful already? Pivot sounds Looooong overdue.

@Luke this is your AWES forum … You know AWES is about scalability… Making bigger wind power systems doesn’t mean they can only be huge. You must know there are realistic use cases for AWES ~5kW.
People exist in remote and rural (not in a city imagine) parts of the world with good wind resource and open space. Those same design classes can be scaled from small to >5MW >5TW

As for the term Hobbyist… Who in AWES is a hobbyist? Anybody?

Yes AWES is urgent and YES the most massive job is decarbonising the electricity power grid system… We need to decarbonise the whole of power infrastructure. Best we get on with it every which way we can please.

I believe a lot of yo-yo system nameplates were quoted in terms of the equivalent nameplate standard turbine device after an estimated improved capacity factor was considered…

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Stopping yoyo and flygen systems would be a mistake. Doing only them would be another mistake.

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I’m not aware of any changes in system architecture. But everyone’s still developing, still having things subject to change. I’d just like to see something nailed down and released commercially, even if it’s suboptimal. (Must be viable though)

That’s the big question.

Still disagree. Pivots would further delay commercialization. [citation needed]

Yepp. Maybe I misinterpreted what @derek said. The framing made me think of someone wanting to use an awes for a construction project. Connected to a storage system a 5kW generator is definitely useful. I’ve made this thread a month ago to discuss use cases for smaller awes:

:point_up:That would be me.

Honestly, I don’t think AWES will have a large impact in the medium term. Solar has become really cheap and saving energy is the easiest way to avoid emissions. Boring old insulation, not flying etc. We’ve had the discussion about the prospects of awes here The no market Hypothesis and here AWE prognosis .

200 years is how long a molecule of CO2 stays in the atmosphere. There are way too many there already. So - We have to go to zero emissions. total cut. end of emissions.
I’m still going to fly. I want electric planes. (had a lovely family snowboarding holiday in Austria last week … melted another polar bear :slight_smile: :raised_hand_with_fingers_splayed: :fire: :bear: )
I’m still going to heat. I want electric heat-pump heating.
It’s bloody windy where I live and it’s similar at altitude in a lot of places. (Austria is wind dead apart from the foehn) The energy density of solar has massive implications for the area we need to use. High wind is massively energy dense.
If it’s viable to have massive turbines it’s viable to have working AWES.
Chat about Daisy (A very simple - multi kite - scalable - AWES ) was removed from

AWE prognosis .
basically says… AWES could happen if we just pull the finger out and get on with it.

Do you consider all systems apart from Makani and KitepowerBV (By the way neither of whom contribute shit £&£* all to any public forum…) a pivot?
To me, It just seems like their basic architecture can be so massively improved on fundamental levels.

An AWE system is essentially, kite(s) + generator, or blade(s) + generator, or mixtures of both.
Whatever the flavor, there’s always a generator, so a generic system = wind energy extraction design + generator.
Where the design could be YoYo, Laddermill, HAWT etc.
The design defines how efficiently the generator is used.

A design that is 100% efficient will generate the maximum power all of the time 24/7.

YoYo has a very erratic power output over the cycle, giving it an average power of about 30% of the maximum. The design is 30% efficient.

For comparison, HAWT has a steady power output over the cycle, and the average power is close to the maximum. The design is about 95% efficient.

Comparing ‘rated power’ is easy, a 10MW HAWT is the same as a 10MW YoYo, they have the same ‘rated power’ output. They could both light 10000 1kW lamps 24/7.
HAWT nameplate generator size is 10.5MW @ approx 95% efficiency
YoYo nameplate generator size is 30MW @ approx 30% efficiency

So we have to build a 30MW sized YoYo, to get a 10MW ‘rated power’ output.

Note : nameplate power output is the maximum power output of the generator, just like in the hardware stores for sanders/grinders etc (labels attached to the machines).

Laddermill (Doug, Rod & Christof) is a better design than YoYo and FlyGen, because Laddermill promises a steady power output.

The reason that there are no products yet (of any design) to buy in the hardware store or for utility scale customers is simple. Launch and landing. Companies can not endurance test their products day and night, if a dedicated support team have to live at the field month in month out, to manually do this.
Automated launch and landing isn’t reliable yet.

I used to think that too. But no, it is much worse. Current estimate is that one-fifth would stay in the atmosphere for tens of thousands of years. And a big percentage of the absorbed CO2 goes into the ocean, leading to ocean acidification. Together with ocean warming and overfishing this will lead to dead oceans in a little while, where now already the situation is dire.


Not sure if I understand the word correctly anymore. I’ve figuratively interpreted it as performing a major change in direction. I have not seen any of those. So the non flygen or yo-yo can only be a pivot if they have previously worked on something different.

I’d be happy to see anything in economically viable operation. Improvements can still be made after and probably better funded and with more data.

The natural interpretation of 100% efficiency is that the machine outputs 100% of the work put into it, which is impossible. In the case of awes that would be 100% of the wind in a defined volume or swept area. @PierreB seems to know most about these things. Betz limit and power available in the wind

But let’s go with your definition:

There is no physical law dictating, that the relationship between average and maximum power. We’ve got the one paper you quoted, but we don’t know the estimates of other developers. For example reel in phase might have become shorter.
By the way: It looks like they weren’t actually generating electrical power in that Article but only measured line length, and tether force and calculated the power from that.

By your definition of efficiency that holds true.^^ I doubt the relationship between maximum power and average power is meaningful. It would be better to just compare average power of systems which cost the same.
Seemy like you’re talking about the capacity factor. Solar, for example has a very low capacity factor of about 0.3 and is still one of the best ways to generate electricity.

Yepp. Automatic operation in general. Would need to be a damn large system to make it economically viable to have people there and then they couldn’t just move it manually.

I propose a challenge, a video demonstration of the first commercially viable AWE design. Of course, the prize would only be a place in history.

It’s a simple challenge, run your Laddermill for 1 hour, and collect the wind speed and power output every second (or a faster sampling rate). Then plot the results on a graph, horizontal axis is time, and vertical axis is 2 plots, power output and wind speed.

If the power output is steady (for a given wind speed), you have won. If the power output is erratic, the system performs like YoYo and FlyGen.

Note that the wind speed and power output measurements should be collected as pairs, so taken at the same moment.

Roddy: You and I are some of the few people who know what it’s like to live in a very windy location. I hear about storms and hurricanes and think “That’s a normal day in this mountain pass”. The last couple of storms brought us snow in the local mountains for skiing, and

  1. Rolled a 25-foot-tall wood and steel “oil-derrick” style tower (laying on the ground, not upright) weighing hundreds of pounds across the yard;
  2. Flipped over a cast-iron-and-wood “park bench”
  3. Blew cast-aluminum chairs across the yard;
  4. Caused a failure requiring at least a service call of a 22-foot-diameter 10 kW turbine on a 120-foot tower, all weighing several tons;
  5. Blew over many many trees in the high winds with wet soil, to various downwind angles, requiring weeks of work to pull upright and secure with stakes, ropes, etc., and severe trimming far beyond what would be normal.
  6. Blew over long woden fence requiring more stakes and lumber to push it back upright in several places
  7. Water leaks on not only roofs, but windows and doors facing to windward including flooded garages from water being blown in under the doors
    I’m sure I’m leaving a lot out, but you get the idea.
    When you’re outside in it, you can barely walk.
    Yup, windy areas: almost impossible to just live in…
    Mostly, it’s a battle for survival.
    People have no idea.
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I’d say without going into specific numbers, capacity-factors, Betz limits, intermittent cycles, storage, nameplate-this-and-that, something useful or promising will be self-explanatory, probably not requiring a lot of explanation or analysis to convince anybody.

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Some commercially viable generators :

Type			Fuel

solar panel 		light
hydropower 		water
HAWT 			wind
diesel generator	diesel

The goal is to put an AWE entry into the list.

Given a constant fuel supply, none of the generators in the list has an erratic power output.

The ‘challenge’ isn’t optional, it’s part of the development process. YoYo and FlyGen have taken the challenge, and failed, the results (erratic power output) are in the first AWE book by R.Schmehl et al (Springer 2014). If the competition is weak, an inefficient design can still succeed, but Solar and HAWT grow stronger each year.

Utility Scale generators use LCOE (Levelised Cost Of Energy) to differentiate viability. LCOE basically means price and performance. One is no good without the other. A cheap system that produces very little power, or a high performance system that costs a small fortune, will both have a poor (high) LCOE.

Of course, there are different markets and competitors (see Lazard yearly report for LCOE).
a) onshore small/medium scale : diesel generator (LCOE approx 30 cent/kWh)
b) onshore utility scale : solar (LCOE approx 5 cent/kWh), HAWT (LCOE approx 5 cent/kWh)
c) offshore utility scale : HAWT (LCOE approx 10 cent/kWh)

YoYo and FlyGen have benefited from big investments. If another AWE design (e.g. Laddermill) is demonstrated to produce 3 times the ‘rated power’ output using the same generator (hence a lower LCOE), the investors will arrive.

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The erratic power for both yoyo and flygen systems is due to the crosswind motion, as the elevation angle varies during the figure. Adding the reel-in phase for the yoyo system where some energy is spent.

Smooth constant power for grid energy normally comes from gas or steam turbines… polar arrays of multiple small blades on wide diameters and multiple stages too… Which AWES rig does that remind you off?
The tilted hollow axis, multi stage, ring mounted multi kite rotor
Well I call it Daisy

Annoyingly - There’s a company called kite turbines
(Must have realised their blades would be better off in tension)

Diesel generators are noisy and reciprocal piston motion is inefficient.

I think the laddermill vs single kite problem is kinda analogous with transistors…
You can still make a transistor from a vacuum tube (and some people pay a fortune for that
but just try packing them by the billion into a useful, reliable arrangement, which is easy to use and portable. modular silicon cellular structures won

Also annoying:

Unwind - release the pressure
That’s the key to kite survival