
Generate energy with kites - handpickednames
http://kitex.tech/
======
random3
Highly related: [https://x.company/makani/](https://x.company/makani/) founded
by Don Montague, one of the Kiteboarding pioneers - likely the first one to
create software to design kites and windsurf sails.

~~~
seltzered_
They mention Makani and others in the "competitive landscape" section of their
site.

~~~
jpm_sd
What they don't mention is that Makani has thoroughly proven that the concept
is not viable. The wing-on-a-string is too unstable and too expensive to
compete with plain old wind turbines.

Edit: removed unsourced claim about the future.

~~~
Grustaf
In what sense have they proven this?

~~~
sjburt
It's been 11 years and they are still barely flying a not-full-size prototype.

~~~
drewm1980
That is not a long time for something like this.

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timthorn
Kite Power Systems
([http://www.kitepowersystems.com/](http://www.kitepowersystems.com/)) came to
give a talk to the Institute of Physics in Cambridge earlier this year. They
use a dual kite system where one kite is generating whilst the second is being
pulled back in, and having demonstrated a 40kW system are about to deploy a
500kW system.

~~~
ZenoArrow
Looks promising. My only question would be, how do they plan to recover the
energy from the devices? Did they cover that in the talk in Cambridge?

~~~
cracell
What you mean? There's a cable on the tether so the drone/kite is always
connected to the grid. Same as a traditional turbine.

~~~
ZenoArrow
Oh okay. The video on the site implied they'd be taking the devices into deep
sea environments. I guess there's still restrictions on where they can be
used.

~~~
timthorn
They are (for some values of deep) - KPS is looking at deployment offshore,
where the tether will be less of an issue, they can go to scale and the wind
is more reliable.

The kites are expected to be cheaper to maintain and install than traditional
turbines, and can be mounted on old turbine bases.

------
slau
I've shared an office space with Andreas and Gustaf for some time in
Copenhagen (they're currently located in the great Founders House workspace).
They're an awesome, extremely passionate team. It's been great fun seeing them
work on the prototypes, and sitting in a bit, asking a bunch of questions, and
Andreas sharing everything he knows about building drones, and all the cool
tips he's willing to share.

If you think drones are loud, wait until you've heard an industrial kite/drone
combo take off in an empty office space.

------
dietlbomb
I see stories promoting kite energy harvesting every couple years. They never
address (one of) the primary obstacles to a functional unit: transmitting the
energy to the ground. They usually hand wave the problem by saying there will
be a conductive tether, but they don't mention the challenge in designing a
tether that is strong enough to hold the kite, while also conductive enough to
transfer power, while light enough for the kite to stay airborne. The usual
solution for ground based power transmission it to use a high voltage, but
that requires significant insulation separating the conductors, usually air.
Other materials tend to fail under high voltage. So they will be limited in
maximum voltage, and be forced to have a larger diameter conductor. It would
be too heavy and won't fly. Tldr; this is probably a scam.

~~~
Grustaf
A scam? That's one elaborate scam! I mean you have some 40 organisations
around the world working on kite energy, including Google X and several
leading universities. It's almost like it would be more impressive if it
actually were a scam. But it's not of course.

As to the tether, people are of course aware of the requirements it needs to
fulfil, you can even find calculations about it online. Making it strong
enough and still light is not a problem, the challenge is really in combining
a structural tether with a conducting cable. It is a challenge, true, but it's
far from impossible and there are several possible designs.

Makani's 600 kW prototype:
[https://www.youtube.com/watch?v=An8vtD1FDqs](https://www.youtube.com/watch?v=An8vtD1FDqs)

~~~
Houshalter
Bad ideas often get funding and support from prestigious seeming institutions.
Look at the stupid waterseer thing:
[https://www.youtube.com/watch?v=LVsqIjAeeXw](https://www.youtube.com/watch?v=LVsqIjAeeXw)

------
beneater
Real Engineering did a video about this recently:
[https://www.youtube.com/watch?v=vMTchVXedkk](https://www.youtube.com/watch?v=vMTchVXedkk)

~~~
yessql
Good video. They said costs could one day get down to $50 per MWh.

We already have solar plants selling at around $30 per MWh, so that doesn't
seem like it will be a major source, although it has the potential to run all
day and all night, unlike solar.

------
scblock
I feel like a broken record (to myself) because every time I see these
concepts I immediately conclude they have no viable commercial future and are
a waste of everything except enthusiasm. That's too negative, because that's
how some of the old coal guys still see wind in general, but it's not
completely crazy. History shows that something like this will get 5-10 years
of development money, make a small scale working concept (maybe), and then go
nowhere.

I guess I don't know what the answer is. Pursuing new ideas is worthwhile, but
I don't expect this company to have real commercial success.

~~~
bujak
Well there have been dozens of kite energy companies in the last decade and
they didn't make it

~~~
jsloss
Yup. That might be because it's never going to work. Or it might be because
it's just not the right time.

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obilgic
Not sure If it would replace the regular wind turbines with being cost
effective, however could be used as a mobile energy generator.

~~~
drewm1980
Most of the soft kite designs target this space, i.e. small generators for
disaster areas and war zones. Soft kites aren't anywhere near as efficient as
hard wings, but they sure pack up small.

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brudgers
In June, I drove across North Texas on I40 and marveled at the scale of the
wind turbines. At those scales (Panhandle I and II generate 400MW according to
Wikipedia), I suspect that per turbine materials cost is less of a limiting
factor than site acquisition and infrastructure installation. I also wonder
about modeling multi-unit installations as shifting wind direction and
intensity changes local conditions and moves one kite turbine relative to its
neighbors.

It's an interesting approach.

~~~
agumonkey
There's also research about Dynamic position adjustments to benefit from air
flows.

~~~
brudgers
As I drove the landscape, I was looking at the spacing between turbine rows
and thinking about dirty air and laminar flow (why Texas is a good place for
wind farms). Probably because the previous week I'd watched a bit of Americas
Cup on TV with a friend who sails.

In the long run, it might be possible to achieve higher energy density with
kites due to dynamic repositioning. The economics of increased complexity for
higher density might work out, but I suspect that the density would need to be
significantly higher while maintaining similar consistency of output.
Feathering a fixed turbine offline in high wind and spinning it up again as
conditions become favorable looks quicker than cabling in and cabling out
kites in similar conditions.

~~~
jxramos
is "dirty air" nothing more than particulates suspended in the wind gusts or
is it some special term of art? Just curious, is there a relationship between
dirty air and laminar flow?

~~~
bathMarm0t
This may not be 100% accurate in nomenclature, but it gets the point across.
Laminar flow is uniform and very easy to model mathematically, hence the
reference to its "clean-ness" (e.g. clean [simple yet functional] design,
clean [elegant] math proofs, etc). Its opposite: turbulence.
laminar:turbulent::clean:dirty. You get turbulence/wake when there's something
upstream of you disturbing the flow patterns. Air has less potential energy in
it once it has been disturbed (the random motion of turbulence detracts from
it's ability to generate pressure differences via flow manipulation). Riding
in dirty air happens when the rich man's yacht in front of you sails upwind of
your own personal rich-mans-yacht. Your vessel can still sail, but will sail a
little bit slower, due to there being less available energy in the wind for
you to tap into. This becomes a problem w/ turbines for obvious reasons (ask
yourself why they don't just put multiple turbines all on a spoke for cost-of-
installation savings, or even why they always seem to choose 3-bladed turbines
[a very cool/interesting mathematical optimization problem!]).

~~~
brudgers
Turbulence isn't always energy robbing, e.g. drafting in cycling and auto
racing and distance running. Though it is hard to operate a sailboat like
that...for what it's worth, my friend has a Sunfish these days.

~~~
traviscj
The difference is which direction the energy is flowing. In sailing, you're
extracting wind energy into kenetic energy. In drafting, you're expending
energy from some other source to overcome the resistance of the air you're
displacing to maintain your kinetic energy.

------
drewm1980
If anyone is wondering why a two kite design is interesting, here's a paper by
a colleage of mine:

[https://lirias.kuleuven.be/bitstream/123456789/398835/2/12-8...](https://lirias.kuleuven.be/bitstream/123456789/398835/2/12-83.pdf)

The tether is a surprisingly large component of the system's drag. With the
two kite design, most of the tether is stationary.

------
Jedd
New Scientist ran a story[1] in 2000, covering Bryan Roberts - a professor an
engineer at the University of Western Sydney in Australia - and his plan to
build 'gyromills' that used wind power to stay airborne, generated
electricity, and transferred that back to ground with a tether. He'd built his
first proof of concept device in 1986.

Hadn't heard much about it since, but am reminded of the proposal every time
someone comes up with a comparable design -- to generate electricity at high
altitude, where where winds are consistent and strong, and property prices are
low -- using some lighter than air or self-propelled vehicle.

I see the gyromill plan has since morphed into a company SkyWindPower[2] and
appears to look more like a 4-prop drone now, coincidentally.

[1] [https://www.newscientist.com/article/mg16722574-800-reach-
fo...](https://www.newscientist.com/article/mg16722574-800-reach-for-the-sky/)

[2] [http://www.skywindpower.com/](http://www.skywindpower.com/)

~~~
aokholm
Gyro mills are very fascinating, but I wouldn't have high hopes for them as
sources of low cost energy. That is unless you could also fly the gyro mill in
a crosswind manner.

This article by Moritz Diehl describes very well the expected power output for
a crosswind device.
[https://pdfs.semanticscholar.org/f5da/681fe152e5a81264f8a919...](https://pdfs.semanticscholar.org/f5da/681fe152e5a81264f8a919d3222cba7f45d4.pdf).

Also it's important to note that the potential power output for any of these
systems are proportional to the cosine of the tether angle, meaning that most
of the advantage airborne systems to traditional turbines won't be so much
that they can reach higher winds, but just the smaller amount of material
required.

------
a_imho
Reminds me of this underwater kite project [1].

I was not able to find the numbers, but they would be interesting. Why not
share them?

[1] [http://minesto.com/](http://minesto.com/)

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ams6110
What happens when the wind stops blowing and all the kites crash to the ground
in a tangled mess?

~~~
drewm1980
With this design and makani's you hover under grid power and land like a
quadcopter. Same for takeoff.

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skadamat
Reminds me of Makani Power! Super cool

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randomerr
I would think that the maintenance and cost to constantly (re)deploy would
negate the earnings.

If its not windy enough, you have to take them in. Too windy or rainy, then
pull the kites back. Wing is ripped or bow is cracked from wind or sun damage,
time to rebuild.

~~~
Grustaf
This happens automatically, so there is no real direct cost. It of course
requires pretty sophisticated autonomous control systems, but the cost of
developing that is amortised.

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Grustaf
Here's an excellent and accessible article about the principles behind kite
energy:

[http://cdn.syscop.de/publications/Diehl2013a.pdf](http://cdn.syscop.de/publications/Diehl2013a.pdf)

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stillhere
What happens when: there is no wind, a flock of geese crash into it, the cable
snaps, etc? Better keep these things away from buildings or it will be like
9/11 all over again from multiple angles.

~~~
drewm1980
As far as I know, there are no plans to fly them over populated areas.

