

Makani Power, a Google funded wind energy startup, comes out of stealth - miratrix
http://www.makanipower.com/

======
jacquesm
Wow, where to begin. First off, I'm really happy that Google continues to fund
energy related start-ups, their solar and wind efforts are commendable.

Also, I'm fairly sure that the engineers behind this project are top notch and
giving this project all they've got, it sure looks like they have picked some
interesting challenges.

That said, I don't think this will ever 'fly' (pun intended) on any
appreciable scale.

Wind is a fickle thing, and if you look at the design parameters of even the
smallest windmills you realize that it takes bullet proof engineering to get a
windmill to operate at all for any stretch of time without catastrophe, tying
one to a kite seems to compound those problems to the point where even if the
power generated were substantially higher than that on the ground you'd still
be left with a higher per KW bill. Being able to operate in places where
windmills are otherwise not viable is nice, but at 600 meters above the ground
there will be substantial risk from getting kits entangled so the closest
spacing will probably be such that a 'farm' of these will generate relatively
little power for a given area of the planet over which the kites fly.

1 MW seems to be a pretty ambitious goal for a first setup, think about it, a
1 MW turbine sitting on the other side of a line will pull on the tether with
a very impressive force, the kite will have to pull aloft a tether strong
enough to withstand that force and up to 600 meters of power transmission
cabling. These are not simple challenges. What I don't understand is why they
don't build a 10 KW or so scale model and gain experience from that before
going for a full MW, even a 10KW system flown for a year or two would give
them plenty of experimental data to help design a larger one.

Then there are the liability issues, windmill towers are pretty solid and yet
they've been known to fail. I figure the failure rate of kite lines+power
lines would be substantially higher than that of a tower and so you'd have to
contend with the occasional free flying kite+windmill combination.

All that said I wish these folks best of luck with what they're doing, but
unlike the cheap solar panel revolution I highly doubt that this will ever be
deployed at a scale large enough to be notable. Neat project though!

~~~
graphene
I was ready to be all sceptical too, but I actually came away from the site
quite impressed.

They seem to say that their wing tracing out the movement of the tip of a
turbine, as well as operating at higher altitude will increase efficiency.
They also have dynamic control systems to deal with variable conditions,
increasing reliability.

As for your windfarm density reasoning, I think the vast majority of
potentially viable land is currently unused, so achieving high density is not
an issue now (although it might become one in future); there is more than
enough land area to go around. Also they mention as a selling point of their
system that it would be much more suited to deep sea locations than
conventional turbines, opening up even more space for potential exploitation.

Concerning the need to build a scaled-down prototype, I think they mentioned
somewhere that the pictures on their site are of a 10kW prototype :-)

About the liability in case of failure, they mention that they have
implemented redundancy of systems on the wing itself, so in case of wing
failure, it can still be brought down safely, and in case of tether failure,
it can fly autonomously to a predefined location.

The only thing I don't understand is how they prevent the tether from getting
all twisted up while still transmitting power through it (although I'm not a
mechanical engineer, so there's probably a relatively simple solution to that)
:-)

As I said earlier, I'm very impressed. This has got me excited.

~~~
jacquesm
Thanks for digging further, I read most of the site and I missed the 10KW
prototype thing (it is the sensible thing to do, and I'm glad they did it).

The reason why I'm skeptical is because systems that are 'far out' in wind
power have been proposed over and over again during the last decade each with
even better on paper performance than the last one. Then as soon as a full
scale model is tried it turns out the economies aren't there any more for some
subtle reason (and sometimes not so subtle).

The wing tracing out the movement of the tip of a turbine makes the wing a
turbine, there is no way around that, and as such it will be governed by the
same laws, there are no exceptions from that. 1MW is not just 2 orders of
magnitude more complicated than 10KW, it is probably more like 3 or 4. I've
hand built a 2.5 KW machine, I'd be very careful to extrapolate my hard-won
knowledge to a machine that is only 4 times as powerful.

For lower power levels a slipring arrangement is customary to avoid twisting
up the cable inside a windmill tower, at higher power levels the mill is
usually steered in such a way that the cables will not tangle.

I'm very curious how this will develop, I'm a huge fan of renewable energy but
I've been around the awea boards long enough that I'd like to see some longer
term results and at higher power levels before getting really excited. I do
sincerely hope they succeed, time will tell, and google backing these guys is
simply awesome.

------
dalton
I used to live in a co-op with Corwin (the CEO/CTO). The main thing I remember
about him was that he was really into kite surfing.

He was also scary smart and about as good of a mechanical engineer PhD as I
have ever met.

Him being the CEO/CTO of makani makes a whole lot of sense.

Good luck, makani!

~~~
c1sc0
Interesting, when I saw the video I was immediately thinking it must have been
a kiter dreaming up this contraption ;-)

------
troygoode
_"Makani AWTs will produce energy at an unsubsidized real cost competitive
with coal-fired power plants, the current benchmark of the lowest cost source
of power."_

If this is true, it could be huge. Would these be deployable basically
anywhere that is reasonably open?

~~~
prbuckley
In the "Fundamentals" section of the website
(<http://www.makanipower.com/concept/fundamentals/>) Makani claims that their
system can operate in 85% of the areas in the US vs. traditional windmills
that need class 4 wind which is only present in 15% of areas in the US. Also
there is some interesting info about why their approach could be better for
offshore wind generation.

I know some of the Makani guys and they are the real deal. These guys are
seriously smart, and talented. I am glad everything is going so well for them.

~~~
c1sc0
Offshore wind generation seems to be an obvious win, although the materials
will have to be tougher.

------
cmurphycode
This looks pretty interesting. They have some nice explanations of their
concept- particularly the fundamentals link:
<http://www.makanipower.com/concept/fundamentals/>

It looks pretty complex, but if the numbers work out right, this is probably
the cheapest way to tap into the great winds available high in the sky.

------
tlack
It's an interesting idea (more wind higher up, without the expensive tall
shaft required for a regular wind turbine), but how does it get relaunched
when it falls to the ground? Wouldn't a balloon or regular kite be simpler and
just as effective?

~~~
hugh3
_how does it get relaunched when it falls to the ground?_

I'm guessing: the same way you'd launch a regular kite: by starting with it
off the ground and slowly letting out the line. Possibly the propellors can be
switched from generators to motors if it needs an extra boost.

A balloon would lose too much in drag. If they can actually solve the software
problem to get these things up and flying autonomously, it'd be pretty darn
effective.

~~~
jemfinch
Why guess when the answer is clear on the second frame of
<http://www.makanipower.com/concept/makani-m1/> ?

------
tsally
The anser to the FAQ "Will this harm birds or bats?" was obviously crafted
with the careful help of a PR and Legal team. :-p

<http://www.makanipower.com/faq/faq/#2>

------
aufreak3
The contrarian in me has always been curious about how tapping "eco friendly"
energy sources impact the environment. (Any here have some serious pointers?)

For example, if the energy of the wind at high altitudes is tapped, the wind
will (duh) lose its force. How will that impact weather systems?

Same for solar power - we'll be trapping radiation that will otherwise be
reflected back into space. How does this affect thermodynamic equilibrium?

Same for geothermal energy - how does it affect deep-earth physics?

Maybe the effects in these cases are indeed linear in the small - like taking
a drink from a river, but it is hard to be sure about whether they can be
scaled with continued linear behaviour. Just as with fossil fuels ... one car
probably didn't do much damage. 8 orders of magnitude later, its a different
story altogether.

~~~
jacquesm
There is an easy way to see why this would not happen. A mountain range is a
pretty sizable obstacle to the progress of airflow. It affects the weather
directly around the mountain, and as much as 50 miles _before_ the mountain
and after it. But that's as far as the influence extends, and you'd need some
pretty good data gathering and analysis to prove that. The effects that you
can actually feel with your senses usually don't extend more than 10 miles or
so beyond the mountain in the leeward direction, upwind you'd be hard pressed
to notice any change at all.

There will _never_ be a windfarm that has a cross section comparable to a
mountain range.

~~~
Tamerlin
That's not a good answer here.

A mountain range isn't sucking the energy out of the system and sending into
another one. The mountain range sucks the energy out of the air and transfers
it elsewhere -- leading to the violent and unpredictable weather that large
mountain ranges are known for.

Turbines suck the energy out of the air and don't put it back in the same
place.

I don't think that we'll be able to draw enough energy out of the air to make
more than micro-climate level changes, but then if you look at what's
happening to the eastern Washington water table and the massive reservoirs on
the Columbia River, the massive reservoirs on the Colorado, and so on, things
start to look a little bit less promising.

~~~
jacquesm
You are missing some basic stuff here. A mountain range is _more_ , not less
effective at 'sucking energy out of the air', it's basic physics. A windmill
can only oppose the wind so much before it fails to work (see Betz' limit), a
mountain range can suck 100% of the energy out of the air as you word it by
simply converting the energy in the air to heat on impact (that's simplified
but that's a good part of it).

As to your choice of words, turbines don't 'suck energy out of the air', they
slow down the moving air. A mountain range does the exact same thing.

~~~
Tamerlin
Read my post again. I did not say "mountain ranges don't suck energy out of
the air."

BTW, turbines don't 'suck energy out of the air', they slow down the moving
air

Those two statements are identical. Slowing down is sucking energy out of it.

------
keeptrying
This is an incredible idea and an amazing feat of engineering. I'm sure
they'll face huge challenges in deploying this thing but it just shows that
real engineering is still alive. Damn, makes me wanna break out my fluid
mechanics textbook :).

------
extension
Did they convert a fire engine into a mobile ground station?

[http://www.makanipower.com/wp-
content/uploads/2010/06/IMG_70...](http://www.makanipower.com/wp-
content/uploads/2010/06/IMG_7011.jpg)

EDIT: yup

[http://www.makanipower.com/wp-
content/uploads/2010/07/201006...](http://www.makanipower.com/wp-
content/uploads/2010/07/20100610-IMG_2189.jpg)

------
hop
This looks way better than than the giant fixed turbines they are putting in
Eastern Oregon which cost $2.4 million a pop, interrupt the view, and can't
pay for themselves.

It's also funny Oregon has abundant hydroelectric power, but subsidizes these
wind projects with rate hikes and taxes - while selling billions of dollars of
these electrons to California at market rates.

------
jamie
I thought this was Saul Griffith's startup, but I see no mention of him on the
about page. At his Long Now talk last year, I recall him talking about Makani
as being his new effort.

<http://en.wikipedia.org/wiki/Saul_Griffith>

Saul seems totally awesome; his Long Now talk "Climate Change Revisited" was a
fantastic survey of alternative energy solutions, and how no one was the
answer, but that a cocktail of solutions is. His ability to put big numbers in
context was stunning, especially his equating of industrial output in the US
pre-WWII to the effort required to build wind turbines to cover half the usage
of the current US electricity grid.

Here's the video of the talk:
[http://fora.tv/2009/01/16/Saul_Griffith_Climate_Change_Recal...](http://fora.tv/2009/01/16/Saul_Griffith_Climate_Change_Recalculated)

------
goooooaaaalll
Joby Energy is another company in the area working on this problem.
<http://www.jobyenergy.com/>

------
hartror
This idea has been batted around for a while and in fact the biggest risk to
getting a project like this aloft will be regulators like the FAA.

------
thibaut_barrere
The concept looks amazing!

I'm a bit concerned about how to protect human lives around - will it be
required to forbid access to a large area ?

The FAQ states that the peak altitude is 600 meter. Does that mean a circle
with a radius of 600m must be protected ?

Pretty sure they thought of it already, it looks like a well thought out
project, I'm just wondering.

~~~
extension
There is so much flexibility in where these can be deployed that you would
probably never find them near a populated area anyway, just for economic
reasons. They can also be deployed at sea much more practically than a tower
turbine.

EDIT: according to the FAQ, there are failsafes for both navigation and tether
failure. It can even land itself untethered!

------
tjlynn
Since this is a hacker site, any control theorists in the house? From
observation and experience, controlling a tethered airplane is the most
pressing technical challenge facing the team right now. Anyone ever modeled
the dynamics of a glider or a turboprop?

------
mdolon
The only question I have is: how does it deal with harsh weather? Especially
with offshore setups where storms are frequent, can it handle high winds and
strong waves?

Overall it's an incredible step towards innovation in energy, kudos to the
entire team.

------
smhinsey
They are mentioned on Discovery Channel's Powering the Future. I believe it
was Saturday's episode. It has interviews and demos. No mention of Google but
they do say they feel their problem is control systems for the kites, not the
actual energy generation.

------
known
Hope Google also invests in solar powered
[http://www.bogolight.com/ProductDetails.asp?ProductCode=BOGO...](http://www.bogolight.com/ProductDetails.asp?ProductCode=BOGO-
BUYONESN2&Show=TechSpecs)

------
aheilbut
What happens when the wind stops blowing or changes direction?

~~~
diziet
It lands! (The tether gets it done, and the rotors also back up as engines)

------
wooster
So, uh, a bunch of my friends are working on this:

<http://www.jobyenergy.com/>

Which is pretty awesome.

------
yuan
If they can make it work, this could be perfect for powering ships, too.

------
ph0rque
So, does the M1 produce 1 MW on average, or peak?

~~~
brainsik
1 MW is the rated capacity. The actual amount of energy produced depends on
where it is deployed. They go into detail about how much energy is produced on
the "fundamentals" page:

<http://www.makanipower.com/concept/fundamentals/>

------
daychilde
So... do they makani power?

------
borism
Rotors are tiny compared to conventional wind turbines. Even with six of them,
just no comparison. Sure they harvest the wind much higher and it flys in
circles quite fast, but I'm not quite sure how they'll be able to generate 1MW
with on of those production things. It has the wingspan of B737!

It's a neat idea, but do benefits outweigh problems?

~~~
krakensden
I was under the impression that most of the reason conventional wind turbines
are so huge is so they can have the blades move slowly, to be more hospitable
to local birds.

~~~
jacquesm
That impression is completely wrong.

The tip speed is what counts, the key governing factor is called the 'tip-
speed-ratio', the apparent wind speed (as seen by the tips of the rotor)
versus the real wind speed (as seen by an observer relative to the ground).

Almost all windmills that want to be efficient have design TSRs somewhere
between 6 and 8, and consequently, in a given wind they all travel about as
fast at the tips.

The design constraints are the speed of sound and the forces on the blade root
as well as the tendency of the blade to start fluttering.

It has absolutely nothing to do with birds. Birds will fly in to a stationary
building just as easily as they'll fly in to windmills, it's rare but it does
happen every now and then.

The larger a windmill, the slower the blades will rotate.

The reason why they are so large is because the power harvested by a windmill
goes up with the square of the rotor diameter, many small windmills are more
costly to maintain and operate than a single larger one. Right now the sweet
spot is somewhere around 2MW and 80 meter rotors for best $/W.

~~~
erikpukinskis
_The reason why they are so large is because the power harvested by a windmill
goes up with the square of the rotor diameter_

Doesn't the Makani wings get around this issue by equivalent to a turbine with
a massive wingspan and a wingtip that generates power, but without the rest of
the structure?

~~~
jacquesm
The outer third of the blades account for roughly 60% of the total power
generated by a windmill, the 'massive wingspan' would have to be normal to the
direction of the wind, in order to say more about what Makani does or does not
do there would have to be a lot more design data available than there is now.

Windmills with 'just the tips' have been proposed and constructed, there are
some good reasons to include the blade all the way to the root. Part of that
is to stem vibration, also to help with rotor start-up and low wind
conditions.

~~~
erikpukinskis
It is normal to the wind direction, that's clear on the site. From the way
you're talking it doesn't sound like you bothered to even look at what they're
doing.

------
noverloop
my nephew got recruited by a similar wind startup.

<http://www.jobyenergy.com/tech>

~~~
relix
Looks like they're still some time away from having a working prototype
though.

------
CptMauli
This will not work. It uses too much space and It looks like it will need
repairs or at least maintenance all the time.

