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Flying kites deliver container-sized power generation

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Re: Flying kites deliver container-sized power generation

#71

Post by londons_explore »

6gvONxR4sf7o wrote: post #68

I used to work on this at a different company, and I'm glad to see work on it continuing! It's one of those things where the physics works out really great for fantastic power generation, but the engineering is just so damned complex, so it's tough to... get off the ground.

I think the Google approach suffered from too much engineering. Specifically they had sunk too much money and too many people at very expensive prototypes before they'd gotten the design even close to running reliably. As soon as you become a big team, you become less nimble - which isn't what you need when your product still has big unknowns.

They should have started with five 2 guy teams, a year and a budget of $50k each, and tried 50 different ways to get a scale model that could reliably not crash in all weather conditions for a few months on end.

Only when you have a craft that can either survive all weather, or reliably pack itself away whenever the weather changes quickly, then figure out how to scale it up and make it generate power.

Re: Flying kites deliver container-sized power generation

#72

Post by zardo »

jollyllama wrote: post #45
JoeAltmaier wrote: post #2

Gotta be more to it. They blithly say, reeling it in takes a fraction of the energy it generates when it pulls the line out. But that's nonsense on the face of it. I'm guessing, it changes it's wind profile, maybe going edge-on or closing up, to make it easy to pull down again. Gotta be something.

>The energy generated by the system while reeling out is greater than the energy consumed to reel the kite back in. There's something about it that just triggers the "perpetual motion machine" identification heuristic.

On a multi line kite you can control the angle of attack and speed. That gives you the ability to dial the pulling force up and down over a large range.

Re: Flying kites deliver container-sized power generation

#73

Post by thechao »

londons_explore wrote: post #71
6gvONxR4sf7o wrote: post #68

I used to work on this at a different company, and I'm glad to see work on it continuing! It's one of those things where the physics works out really great for fantastic power generation, but the engineering is just so damned complex, so it's tough to... get off the ground.

I think the Google approach suffered from too much engineering . Specifically they had sunk too much money and too many people at very expensive prototypes before they'd gotten the design even close to running reliably. As soon as you become a big team, you become less nimble - which isn't what you need when your product still has big unknowns. They should have started with five 2 guy teams, a year and a budget of $5…

The back-of-the-envelope analysis for kite-based power is very compelling; enough that I tried my hand at designing a kite-powered system in ~2004. I don't think anyone can really appreciate how challenging the engineering (control systems) are for all-weather kite-flying until they just try to reel-in & reel-out a kite on a relatively calm day. I literally couldn't even write-down the differential equation which describes the inverse control path for the kite, when there's one vector for the kite, and one vector for the tether, under the reel-in load; none-the-less, solve the equation, and then get it to work with a freakin' stepper motor.

Re: Flying kites deliver container-sized power generation

#74

Post by michaelbuckbee »

sytse wrote: post #57

This is the best article on the problems of airborne wind energy. It is 10 years old but I think Michael Barnard did a great job explaining all the variants and why it is hard https://czmphorfqgktmzxu.quora.com/Airborne-wind-energy-a-co...

You were not kidding. That article really covered a lot of the obvious questions I had (and was the single best thing I've ever read on Quora).

Re: Flying kites deliver container-sized power generation

#75

Post by patall »

tamimio wrote: post #54
smusamashah wrote: post #20

How is the kite raised initially and what happens when air stops, how is it re-raised? Reading the article seems like it's pulled back if air is stopping, and slowly released based on air speed perhaps.

I wonder how they will deal with bird attacks. Falcons and eagles (ironically, they share the same name with this kite) are territorial and will go after these drones. I once had a huge heavy-lift drone that got attacked too. But with a pilot nearby, the easy solution is to fly to a higher altitude, that seems to determine who rules the sky in their eyes apparently. I’m not sure how this kite will manage such situati…

By being 60m2 big? I mean, helicopters are also not being attacked by eagles, why would this kite be?

Re: Flying kites deliver container-sized power generation

#77

Post by zensavona »

Scea91 wrote: post #61

Interestingly, the very first statement is quite misleading. The statement: > On average, a humble wind turbine uses less land area per megawatt-hour than almost any other power source. The article itself refers to this citation [1]. It says, unsurprisingly, that the most land efficient power source is nuclear. The statement is of course technically true because it says "almost any power source". With wind, however,…

Sounds like the article used just the right wording then.

“…less land area per megawatt-hour than almost any other power source.” As I read it this implies there is one (or some very small percentage) power source which uses less land per megawatt-hour, which is exactly the case.

Re: Flying kites deliver container-sized power generation

#78

Post by saulrh »

Scea91 wrote: post #61

Interestingly, the very first statement is quite misleading. The statement: > On average, a humble wind turbine uses less land area per megawatt-hour than almost any other power source. The article itself refers to this citation [1]. It says, unsurprisingly, that the most land efficient power source is nuclear. The statement is of course technically true because it says "almost any power source". With wind, however,…

An offshore wind farm by definition uses no land area :V

Re: Flying kites deliver container-sized power generation

#79

Post by OtherShrezzing »

Scea91 wrote: post #61

Interestingly, the very first statement is quite misleading. The statement: > On average, a humble wind turbine uses less land area per megawatt-hour than almost any other power source. The article itself refers to this citation [1]. It says, unsurprisingly, that the most land efficient power source is nuclear. The statement is of course technically true because it says "almost any power source". With wind, however,…

I'm wondering if the OWID data takes the 3,400km^2 of exclusion zone from Fukushima and Chernobyl (more like 5,000km^2, see below) into account when calculating the average size of a nuclear plant?

I think if we're saying the space beneath the blades can count towards aggregate wind-power land use, an argument can be made to include nuclear wasteland in the aggregate nuclear-power land use.

Re: Flying kites deliver container-sized power generation

#80

Post by patall »

skyleradams wrote: post #6

Not to be a HN naysayer, but wasn't this tried already with Makani Power?[1] They even made a documentary about it[2] Compared to traditional wind turbines, this solution trades an enormous amount of complexity, maintenance, etc for small reductions in material cost. We should be churning out traditional wind turbines for cheap instead. [1] https://x.company/projects/makani/ [2] https://www.youtube.com/watch?v=qd_hEj…

> Not to be a HN naysayer, but wasn't this tried already with Makani Power?[1] They even made a documentary about it[2]

So? These (kitepower and skysails, but there are more) are long standing 'competitors' of Makani, all existing for far longer than 2020 when Makani went down. Just because Google gave up, not everyone else also gave up. I mean, Google also stopped Google code, groups and google+, yet similar products are still triving.

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