
Google Makani – Wind Energy Kites - krschultz
http://www.google.com/makani/
======
elevensies
I'm still a bit confused about how the forces line up for the flight path. If
I'm understanding:

\- the wing flies in a circle which is perpendicular to the wind (oriented the
same way an ordinary wind turbine would be)

\- the tether is up-wind from the wing, so the force from the tether pulls the
wing into the wind which generates lift, which is used to propel the wing
along the circular path

\- the propellers are driven by the circular movement of the wing, and
generate electricity

So the tether and the wing generate movement, the movement spins the
propellers, and the propellers drive the generator. Except for take-off and
positioning, where they are used as motors. Am I understanding this?

~~~
TylerE
I think that's more or less it.

I think what they're doing is a milder version of dynamic soaring, which is a
popular technique used among RC glider pilots (and some birds).

The speeds attainable are pretty insane, the current RC record is _505_ MPH,
which in a rather fascinating twist is faster than the fastest POWERED RC
aircraft.

This a video that shows a pretty good idea of what it looks like, at
compartively slower speeds.

[https://www.youtube.com/watch?v=DegX_we1Mic](https://www.youtube.com/watch?v=DegX_we1Mic)

~~~
mkl
This video explained dynamic soaring for me:
[https://www.youtube.com/watch?v=SVN-
oF6tPLc](https://www.youtube.com/watch?v=SVN-oF6tPLc)

The key thing seems to be having different wind speeds available at different
heights so you can do the upwind part through slower moving air.

~~~
tim333
Cool. I never knew that stuff. There's a vid here of a guy getting his glider
to 320kph with wind speeds of only 25-30kph before crashing it into a rock
face. Reminds me of my own efforts with a RC glider which crashed into a
concrete pillar at ~50mph quite promptly due to my lack of pilot skills.

[https://www.youtube.com/watch?v=QjWFcYqdgA4](https://www.youtube.com/watch?v=QjWFcYqdgA4)

------
callesgg
Good, could people just stop messing with how scrolling works.

~~~
Thiz
I have a default zooming of 125% and nobody seems to know how to make the web
work for us with disabilities, not even gmail works well.

Scrolling pages always look weird for me. Image libraries like lightbox are a
special pain in the ass.

~~~
proexploit
Would you willing to provide me any detail about the issues you run into with
Gmail?

~~~
Thiz
The most prominent, composing a new email. The floating window appears out of
bounds and it's impossible to click any buttons on the lower bar, including
the send button.

What I do is tabbing all the way down so the floating window reorganizes
allowing me to send the email.

------
ChuckMcM
I think this is pretty cool, but several questions spring to mind which I
haven't found good answers for.

The first is what sort of density can you get out of these? How many per
acre/hectare? 1? 3? California has a number of wind installations and some of
them are pretty dense [1].

The second is what sort of radar signature does this thing have? Probably not
a navigation hazard but should be interesting on the weather doppler display.

[1]
[http://www.jamielaval.com/Images2011/Journal/Tehachapi_windm...](http://www.jamielaval.com/Images2011/Journal/Tehachapi_windmills1.jpg)

~~~
Untit1ed
They do mention density in terms of kw / sqm as being slightly higher than
conventional turbines, but don't give a lot of details beyond that. I can only
hope it's not based on parking them all right next to each other and hoping
they don't get tangled up :p

~~~
bduerst
Imagine if they were aware of each other's locations and made micro
adjustments to their timing to sync each other. They could cross flight paths.

On the other hand, wind isn't uniform enough to really allow this.

------
PakG1
My friend worked for Makani for quite some time. I remember at the time, they
were in financial difficulty and, in his words, laid off all the people who
viewed it only as a science project in order to get lean. Not enough people
were focused on what would be necessary to bring the tech to market. He ended
up finally leaving after some time, but I think before Google took them. A
Google X type of environment probably is perfect for people who like working
on science projects and can't be hindered by financial constraints that would
hold back innovation at this scale. Would be interesting if Google ends up
being able to turn this into something used by many parties worldwide.

~~~
ovi256
I guess they did very well to lay off the people who thought of it as a
science project, because it's obviously an engineering project! All the
science needed to make it work already exists, it's just a question of
hammering it together. Disclaimer: engineer here.

------
antr
The 60% load factor seems a dream come true... well above offshore wind levels
(c. 50%). Having said that, I'm very curious to know the capex per MW, and the
ongoing O&M costs for each of the kites. Onshore wind has experienced a
considerable decline both in the cost of the turbine and O&M... my impression
is that this technology is not going to be cheap to run. Anyone has any
insight?

~~~
ansible
What gives you the impression that it won't be cheap to run?

Presumably, if they've got the automation figured out, each unit will just
manage itself, launching when wind conditions are favorable.

~~~
antr
The underlying technology for the Makani kites and a standard turbine are the
same. In the Makani case you have one kite with eight turbines, and like a
standard wind turbine, all turbines need to be serviced. If you have to
service 1 turbine, the other 7 stop operating. Hence, on a per turbine basis,
I believe availability won't be around the 98-99% level (the industry
standard), but lower.

Additionally you have the tether, a new variable, which is another moving
piece, and will also need to be serviced.

I've done some back of the envelope numbers, and without assuming a higher
capex (which I'm fairly certain it is), on an recurrent basis, an increase in
production doesn't really lead to cheaper $/MWh on an O&M basis.

    
    
                            Standard Turbine	Makani
      Capacity (MW)		1.5			0.6
      Load factor		23%			60%
      Production (MWh)	3,022			3,154
      Availability		98%			95%[1]
      Net Production	2,962			2,996
      O&M $/turbine/yr	20,000			20,000[2]
      $/MWh/year		$6.75			$6.68
    

[1] I think I'm being generous at a 95% availability, but I haven't got enough
data to make another assumption.

[2] O&M can be contracted on a turbine or MW basis. Still, given the
"complexity" of Makani, the price of this could be higher than the standard
cost.

This is a new technology, and not much info is available e.g. how big can
these get, what's the investment cost per MW, what are the potential
maintenance issues, how does availability look like, etc. My above argument is
an educated guess, but I'd really like to know more about it. I really like
the idea and I would like the economics to work out.

~~~
ansible
After they get going, I don't see how the capex could possibly be higher than
for a traditional tower wind turbine. Everything is smaller, and closer to the
ground. Less site preparation, and you don't need to rent giant cranes. You're
also not shipping giant blades and pylons with special trucks.

Also, using smaller generators means that you've got a higher production
volume, which can mean significant cost savings. You're also not dealing with
giant bearings, gearboxes, etc. which are expensive to produce.

And if you're taking a kite offline, you might as well replace all the motor-
generators at the same time. I assume they'll be designed to easily detach and
replace. Then, back at the shop, you can check them out on your test bench,
and see which ones can return to service in the spares stock.

I agree that the tether is a big question mark.

------
lemoncucumber
The New Yorker did a great article about this tech (and the guy behind it) a
couple years ago: [http://www.newyorker.com/magazine/2013/05/20/inherit-the-
win...](http://www.newyorker.com/magazine/2013/05/20/inherit-the-wind)

~~~
sterlingross
Thank you for the link, I was wanting to read that article but had forgotten
about it.

I met Don on a return flight from SJC to OGG. He seemed very kind and
passionate about the Makani Power project at the time. The idea, as he
explained it, originated from plans to build a self powered kite boat [1] that
could circumnavigate the world. The "self powered" part interested his friends
at Google and they started funding him. He confessed that he had accidentally
become an engineer in the process, but his real passion was wind surfing and
kite surfing and he was eager to get back to that.

[1] [http://project.kiteboat.com/](http://project.kiteboat.com/)

------
Jedd
This looks a lot like a project being developed by Bryan Roberts (IIRC) in
Australia, that New Scientist covered about fifteen years ago. He was using a
gyrocopter-like structure (he called it a gyromill) to keep the devices up in
the air, and with an intent to be much higher up than these things seem to be
aimed at, but the principle remains the same (tethered, high enough to gain
some consistency of wind).

Can't find the NS link, but this provides some more info:
[http://www.abc.net.au/science/news/enviro/EnviroRepublish_18...](http://www.abc.net.au/science/news/enviro/EnviroRepublish_182107.htm)

[Edit: add url, fix historical reference.]

------
ryen
The specifics on how it works is in a sublink here:
[http://www.google.com/makani/technology/](http://www.google.com/makani/technology/)

------
igonvalue
> The energy kite simulates the tip of a wind turbine blade, which is the part
> of a turbine that makes most of the energy. The kite is launched from the
> ground station by the rotors, which act like propellers on a helicopter.
> Once in the air, the kite generates power by flying in large circles where
> the wind is strong and consistent. Air moving across rotors mounted on the
> kite forces them to rotate, driving a generator to produce electricity,
> which travels down the tether to the grid.

Are the rotors that launch the kite the same as the ones that generate the
electricity?

~~~
jccooper
Yes. The generators turn into motors if you turn the electricity around.

------
jcchin41
[http://kitepowercoop.org/](http://kitepowercoop.org/)

Looks like there is an open-source community around energy kites. They're
largely focused soft form kites, rather than fast moving rigid wings.

And another rigid wing competitor:
[http://www.ampyxpower.com/](http://www.ampyxpower.com/)

------
grownseed
Please correct me if I'm wrong, but I was under the impression that wind
turbines were effectively unsustainable due to the materials they are made of
and their actual lifespan not offsetting the initial financial and
environmental costs.

Now, I understand that this project is supposed to provide greater versatility
and efficiency using cheaper materials, but it seems to me (by no means an
expert on the subject) that these kites are considerably more prone to damage
by their very nature too.

Honest question, is this really solving a problem?

P.S.: this website is absolutely horrible to navigate.

~~~
krschultz
I've never heard the argument that current wind turbine are unsustainable
before. I don't see why that would be so. The base is concrete, the tower is
steel, neither of which is exotic. The generator is pretty standard. All of
that is industrial tech we invented a century ago, and we know how to maintain
it for the long haul.

The blades themselves are composite, that may have some longevity issues (you
typically need to paint carbon fiber to prevent UV degradation every view
years), but I don't know, they can last for a long time. Fiberglass boats last
50+ years.

I would imagine the designed lifecycle of a wind turbine is 25+ years, and I
also imagine that the bases will last long beyond that. In 50 years we may
have to go around and replace the blades on these things, but that's it.

~~~
giggles_giggles
My understanding is that, among other things, the generators come under
extreme stress during exceptionally windy occasions, causing a lot of wear and
tear that happens way up at the top of these giant windmills.

These require a lot of manual maintenance, which is dangerous and expensive
due to the nature (and location) of the work.

Additionally (and as a demonstration of just how much stress they come under),
while coming under said strain, they've been known to burst into flames
[https://www.youtube.com/watch?v=C_oFPF6Anwo](https://www.youtube.com/watch?v=C_oFPF6Anwo)

As for their lifespan, the government agencies that build them claim 25 years,
but there's controversy about this. Searching online will find you conflicting
studies, including this one [http://www.ref.org.uk/publications/280-analysis-
of-wind-farm...](http://www.ref.org.uk/publications/280-analysis-of-wind-farm-
performance-in-uk-and-denmark), which states

"Analysis of site-specific performance reveals that the average normalised
load factor of new UK onshore wind farms at age 1 (the peak year of operation)
declined significantly from 2000 to 2011" indicating that they may wear out
more on the order of ten years.

Now that was a cursory search but in any case the argument that the wind farms
cost so much to maintain that they're nonviable is not new.

Wind turbines aren't exotic tech, but it is a giant turbine that is placed way
up on a pole, and fundamentally a turbine will need maintenance, so someone
has to go up and do that maintenance, and that's expensive.

~~~
jdmichal
> Additionally (and as a demonstration of just how much stress they come
> under), while coming under said strain, they've been known to burst into
> flames

I thought all wind turbines were built with brakes now exactly to prevent this
and other more spectacular failure modes, like the blades fragmenting. They
have a defined operating range, and if the wind isn't in that range the brakes
engage and the blades don't move.

~~~
69_years_and
Not quite, if the wind is too strong the blades feather (edge on to the wind)
brakes exist but are puny and are only for maintenance use. Some blades have a
tip that the rotates and causes high drag in the event of feathering failing
and going into an overspeed.

------
INTPenis
Call me skeptical.

I live in the land of many wind turbines, the Øresund region of southern
sweden, and I know that they can break down or even catch fire from time to
time. Who is going to service this aeroplane when it breaks down?

It just seems to me that this idea has too many possible problems that could
go horribly wrong from trying to fly a plane around on a teather in strong
winds.

To be honest, before I saw the G+ page and read the top HN comments, my first
thought was that april 1st is right around the corner. ;)

------
camgunz
I think it's fucked up that "modern", "mobile-first" web design essentially
boils down to powerpoint in a browser.

That said, this is a cool idea.

------
robinhowlett
Would it plummet out of the sky if the wind dropped suddenly?

~~~
spot
presumably it would go into helicopter mode and return to base.

~~~
clebio
There's also autorotation, which means you need very little power for a
controlled descent (still need some power to steer).

[http://en.wikipedia.org/wiki/Autorotation](http://en.wikipedia.org/wiki/Autorotation)

~~~
imaginenore
Autorotation only really works for large heavy propellers, like the ones on
helicopters.

~~~
clebio
I don't know. It works for RC helicopters of 500 size or so. I haven't seen
autorotation performed with multicopters, though, so not sure how it maps to
this application. I'm guessing these are fixed-blade machines. RC heli's
manage autorotation via their collective pitch, which RC quadcopters (or
hexacopters) don't have (collective). So it might not be relevant. But on the
other hand, if the value of avoiding a crash is high enough, they could make
the blades collective just for that purpose. Or maybe make one or two of the
multiple props collective... I'd assume they already have a working solution
to avoid falling out of the sky, but then, it isn't mentioned in the copy.

EDIT: There _are_ quadcopters that can fly inverted, but I think they use
powered servos with a reverse polarity. The value of autorotation is that it
works when your main power source dies. So it all depends on the context and
parameters (is there a backup battery of lower capacity available for
emergency situations, say).

------
calt
I'm happy to see experimentation in new wind technologies, but it makes me sad
to see things like this grabbing headlines when floating offshore is such a
strong contender that just needs some more funding for the engineering effort
(mostly because it's pushing the currently tested limits of carbon
composites).

[http://bangordailynews.com/2014/05/07/news/bangor/umaine-
get...](http://bangordailynews.com/2014/05/07/news/bangor/umaine-gets-small-
grant-for-offshore-wind-project-but-far-less-than-hoped-for/)

~~~
krschultz
I don't think they mutually exclusive, but great link.

------
duderific
It seems like if there were a "farm" of these kites, they would have to be
very widely spaced out, or else they would crash into each other or get their
tethers tangled up.

~~~
tjradcliffe
Automated control would handle this easily.

------
modeless
I'm worried about the noise. The blades spin many times faster than a regular
windmill. I imagine it will sound similar to a small plane flying very close
to the ground. Of course a plane flies over once and it's gone; this thing
will produce a constant droning noise that fluctuates in pitch and volume
every few seconds as the kite goes up and down. If you put them far offshore
this wouldn't be a problem, but I wouldn't want one of these near my house.

~~~
ryen
The majority of noise you hear from a small prop plane flying above is from
the engine.

Also, the advanced height they're trying to achieve limits the amount of noise
relative to what you would hear from a small drone overhead.

~~~
elihu
I'm sceptical that that's true. We can put mufflers on gas engines to make
them quieter. The prop, though, is moving a lot of air, and there's no way to
get around that and have it still work.

~~~
mikeyouse
I found an old JPL document detailing "Aerodynamic Noise from Rotors,
Propellers, and Lift Fans"
([http://cafefoundation.org/v2/pdf_tech/Noise.Technologies/NAS...](http://cafefoundation.org/v2/pdf_tech/Noise.Technologies/NASA.1970.Prop.Noise.Review.pdf))
which has some interesting details.

A 300hp hub, spinning a 9ft diameter propeller at 1584 RPM should be roughly
72dB as measured from 1,000 feet. From a mile away, it will be more like 57dB
or about TV volume from 6 feet away. -- Then again, these are spinning far
faster than you'd expect from a wind turbine.

------
jedisct1
Reminds me of Kitepower:
[https://www.youtube.com/watch?v=DjcJljXGW9I](https://www.youtube.com/watch?v=DjcJljXGW9I)

------
arh68
Does this work in the rain? I'm watching the TED talk now but I can't tell.

------
lutorm
They're supposed to be putting up a test installation on the Big Island of
Hawaii sometime this year:

[http://www.bizjournals.com/pacific/blog/morning_call/2014/10...](http://www.bizjournals.com/pacific/blog/morning_call/2014/10/google-
owned-makani-to-test-wind-technology-on.html)

------
hrehhf
It is strange that their map of the USA left off the entire state Alaska,
where electricity is among the most expensive in the country:
[http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm...](http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a)

Makani seems ideal for their needs: "Alaska’s electricity infrastructure
differs from that of the lower 48 states in that most consumers are not linked
to large interconnected grids through transmission and distribution lines;
rural communities in Alaska rely primarily on diesel electric generators for
power. " \--
[http://www.eia.gov/state/?sid=AK](http://www.eia.gov/state/?sid=AK)

------
fillskills
How does this affect birds? How does it affect planes flying in that airspace?

~~~
jonalmeida
Commercial planes don't fly below 250m at all, expect when taking off and
landing at airfields.

The structure of these "turbines" are that of planes which look like large
birds to real birds, so they would stay away from the area with them.

I'd assume that these would be installed in large open fields, so it shouldn't
affect migration patterns or bird localities.

I have seen eagles attack quadcopters thinking they were birds, but those are
usually of similar sizes to what eagles' prey would look like, but obviously
this shouldn't be a problem as well.

------
malandrew
Direct link to video for those frustrated by the scrolling:

[https://www.youtube.com/watch?v=GSYMHzgLLn8&t=20](https://www.youtube.com/watch?v=GSYMHzgLLn8&t=20)

------
tim333
Looks kind of cool. I just looked up the cost of regular turbines are "about
$1.3 million to $2.2 million per MW of nameplate capacity installed." So I
guess for a 600kw kite to be economic you'd have to build them for about $1 -
3m given the kite produces more constant power. Dunno what happens when the
wind drops and all your kites have to land.

------
switchfakie
A german startup for energy kites based in berlin with a working prototype was
even first. [http://www.enerkite.de/](http://www.enerkite.de/)
[https://fundernation.eu/fundernation/projects/enerkite](https://fundernation.eu/fundernation/projects/enerkite)

------
tarequeh
For a second a tried to imagine a satellite view of the earth with many of
these flying. It'd look mesmerizing. I really applaud Google for funding
research on affordable renewable energy. It's unfortunate that the scrolling
doesn't work, but hey the prototype does!

~~~
teddyknox
You mean an airplane view? From the top down I imagine they wouldn't look very
interesting.

------
kevinbluer
Did anyone else read this as Google Mankini?

[http://www.amazon.com/Smiffys-Mens-Borat-Mankini-
Dress/dp/B0...](http://www.amazon.com/Smiffys-Mens-Borat-Mankini-
Dress/dp/B005HMHNX8)

------
manachar
Interesting tech. I wonder if these have lower impacts on avian and bat
populations.

Also, it's interesting that tech companies love using Hawaiian words for
things (Wiki, akamai).

~~~
tjradcliffe
The research I've seen says bats are mostly affected by low frequency pressure
waves from conventional turbines, so these won't have that problem.

They may also spin fast enough to make enough noise to scare birds away, but
they are also _moving_ pretty fast, so could pose a problem for birds at the
low end of their loop, which is somewhat under 150 m.

Putting them on a migration route would be a very bad thing for birds.

------
richardw
Very similar to underwater kites:

[http://minesto.com/deep-green/](http://minesto.com/deep-green/)

------
techdrone
looks like a fun project, but unfortunately wind will unlikely to make the
impact needed on the shift from fossil to renewables.

------
dvh
What happen when I buy one of those, put them in the air and then Google
cancel it, will it crash on the ground?

------
kleer001
What a horribly designed page. It could have fit all on one page.

------
digitalzombie
I want Kinetic Energy Puppies.

------
blairbeckwith
Completely breaks swipe-back gesture in Chrome on a Mac. In a really weird
way. Left and right swiping takes you up and down the page. Really awkward.

~~~
sbhere
Scrolling with a standard pointing device was off too. FWIW. YMMV.

~~~
expose
Acronym professional

------
a8da6b0c91d
Off topic but I have been toying with building a small catamaran powered by a
Darrieus turbine or a kite setup such as depicted. The point is wind powered
navigation of busy rivers and the east coast intracostal waterway. Obviously
this makes zero sense on the open sea or in wide bays, where long tacks are
easy and more efficient. Tacking on the intracoastal is practically infeasible
in today's world, yet there is loads of wind. Can anyone refer me to to prior
art on this?

~~~
Gravityloss
[http://www.boatdesign.net/forums/attachments/projects-
propos...](http://www.boatdesign.net/forums/attachments/projects-
proposals/17617d1197420937-another-idea-upwind-sailing-real.jpg)

------
frozenport
Crazy ideas should come with graphs. Not clear how much it costs, how much
energy it will generate, and how it will recoup the cost.

~~~
humanrobot
check this
[http://www.google.com/makani/solution/](http://www.google.com/makani/solution/)

------
imaginenore
600 kW from one kite is insanely impressive. It looks pretty small. That can
easily power a few hundreds of homes.

~~~
maxxxxx
That number sounds really high to me too. 2000 of them of and you have a
nuclear power plant.

