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thank you for watching >> Cassie Immel: Hello, everyone
I'm Cassie Immel. Tonight, I will introduce.
our speaker, Mitch Bradt. During the years 2005 and 2009
the US Wind Energy Installations
in annual growth rates experienced a growth
In his talk "The Wind Turbine Generators:
The Basics," Mitch will give a
of the fundamental technical presentation on some
maturing energy source. This will includes
mechanical and electrical slides of the energy
conversion process, a sample
as well as the concept of energy production estimates
He'll get into more of of that with you.or.
So, I'd like you all
to wMr. Mitch Bradt.me.
( applause )
Mitch Bradt:
It's really my Thank you, Cassie.
I bring a perspective. pleasure to be here.
and presenting here Iat the university.
I work here at the university.
crowds that are from outside But I enjoy presenting to
Thank you for attending. the university as well.
So, I'll talk to you today about wind
turbine generator basics. I'll also add on a little bonus
feature of a little tour. We're not actually going
to get up and walk
I'm going to actually take you out of here and get on a bus.
electrons move, once we've on a picture tour, on how the
turns into electricity. So we're going to talk about
some introductory material. We'll go through the mechanical
topics, then the electrical.
to torque, torque converts So wind mechanical converts
And then we'll talk about what to electricity.
figure out how much energy capacity means, and how do you
on a yearly basis. you're going to get
of the wind resource Okay, this is a chart
It happens to have been made in the United States.
from Texas named very famous by an oilman
the Pickens plan, signed up T. Bfor 700 turbines fromated
General Electric, walked out
wind turbine market.
(laughs)
As you see, it's been accurately described
in oilman terms, as the Saudi Arabia of wind.
In fact, there is a humongous potential of wind energy here.
It's primarily in that corridor of Minnesota to Montana
from the Canadian border
There's a great deal of wind. There are other places where
there's very, very good wind. In this, as you can see
if you can see in color, the
Now, looking at the installations that have gone
on, here we have a chart
during the year, and also of the cumulative one.ity
I know I've been asked
but I have to for this. Starting here in '95
we have about a gigawatt
about 1,000 megawatts. in the United States
about what a typical That's about, you know
or a big coal power plant produces.
Portage has the Columbia Energy Center.
It's about that much. That's the entire
country of wind farm. Then we have these
little blue bars of increase. If you notice in 1999
there was kind of a pretty big step, right?
Then there was a drop.
Then a step, then a drop. Anyone guess why that got
stimulated, and then didn't?
Tax incentives. Production tax credit.
Congress put it in
Then put it in then let it expire.
And in fact, the developers, and let it expire.
gangbusters to get really, you know, went
and then pulled back. Well, by 2005, they kind
of got wise in Washington and they approved a two-year
and then a three
Now it's been extended more year extension.
of give a little bit for one more year to kind
at least to the business. You can see it really took off
starting at about 2001, or so.
over year expansion in what we were doing.
I will tell you that 2010 the capacity built in 2010
and that's reflected by this multi-color one
was slightly less than 2009.
we had in the previous year. We didn't build more than
to be slightly less but it was a drop of 70%.
So we still have more wind
in the market. but we had a big crash
the crash happened? AnyThere's still all why
these standards that
You've still got customers you've got to meet.
Cheaper natural gas has an paying for green credits.
really the reason ethat caused the crash.
Bear Stearns, AIG.
nobody was lending money The banks crashed
long period of time when you to anybody, so we had a
into Chase or JP Morgan and get a $400 million loan.
They just weren't giving them out for a while.
So we're now at the end of a development cycle when it
hasn't increased as much. That isn't to say that it's
not going to keep growing.
in terms of order entries with the suppliers appears
to be going better. In fact, the world's largest
wind turbine manufacture
has big operations in Colorado a Danish company called Vestas
here in Madison. and a research center
is the biggest year of sales They announced that this
So it's looking up again. inBut it may not be up.
again until 2012, or so.
about power systems. Okay, a little bit
How does energy move How is a power system built?
Well, we start here, and I'm to your house?
I'll try to move it goiso it's easy to see.er.
We start here at a power plant. This could be
nuclear, coal, gas. This building could be a
representation of, you know 100 wind turbines put together.
The power comes out at some what we call medium voltage
15,000 volts would be a medium voltage.
Anything between
we call medium voltage. 5It gets stepped up toat
transmission where it's what we call high voltage.
The highest high voltage
is 345,000 volts. in Places like Ohio andin
West Virginia have 765,000. But these are the big towers
that you see when you're
and you see them running driving on the Interstate
that's moving full power across the landscape - so
from far distant power plants acrosor mutual supportither
from one utility to another like oh, my nuclear power plant
has to go down for new fuel can I buy power from you
so the power moves across the transmission system.
So, it's moving across
It then goes to what we call the transmission system.
is listed here. It may go to sub-transmission
which is more of the same.
but at this point it's a lower voltage.
Because there are several feeders coming
off at sub-transmission there's less power
going different directions. Then it pops down here
at a substation, and you've probably seen these, too.
They look all gray. They're surrounded by a fence.
Sometimes they have signs saying "stay out," and that's
a really good thing.
please stay out of these. IThey're really harmful.re
Then it runs down the street
and probably have miscalled on t"telephone poles."seen
They're actually utility poles. The telephone company gets
to hook on to our poles.
Anyway, along these "telephone poles," excuse me
then to your house or to your business.
That's the way electricity
Okay, I want to take a sidebar makes it's way to your house.
A number of the slides with this slide here.
and introductory. And a few of them, I've taken
out of my real technical stuff
of equations and diagrams and so forth, just let it
wash over you, and just pay attention to what I'm saying.
In controlling a power system and keeping it stable
we need two things to happen. We need the frequency
which in this country is 60hz that means every second
the voltage goes from positive
We need that to stay at 60hz to negative 60 times.
We need the voltage that's at your house
and all over the grid to be about the same all the time.
And based on the flow of power
we can control it. into and out of the system
light bulb in your house Now, if you switch on another
out of the grid. more power is being drawn
to go into the grid. So somewhere, energy has
of light storage, I'll call it. It's only good for just a few
milliseconds, that can handle powering a light bulb
for the first little bit
Then eventually more natural gas has to get
into the turbine, or more coal
or you know, the things that we can control
the power plants that we can
They have to raise their output. dispatch, they have to raise.
in, we can keep the voltage stable and the frequency stable.
If either one of those goes unstable, we get what happened
in 2003 in New York and Ontario,
blackout in the northeast. and you know the great
the mechanical side of wind turbine generators.
Here's a nice picture found in the New York Times that
explains it pretty well.
components that I'll point out. We have, of course, the blades.
We have three of them.
It's known as the Danish That's a very standard design.
get credit for it. because the Danes
upwind turbine. Upwind meaning the blades
are on the upwind side
Connecting the three blades together is the hub.
There's a shaft going into
the tower called the nacelle. That's a French word that
people who are not familiar with aerospace or wind have
not heard, N-A-C-E-L-L-E. The nacelle is basically an
enclosure that holds everything.
various different equipment. Inside the nacelle, you'll have
to raise the speed of the shaft. Usually, you have a gear box
A show of hands. If you've seen those--
driving along the highway have seen turbines?e
Are they spinning fast or slow? Okay, anyone want to care
to venture a guess how fast the tip is moving on those?
Yeah? 130 miles an hour, almost.
(inaudible)
Right at 130? Okay.
A very efficient modern turbine will have speeds
of 150 to 225 miles per hour, typically.
But they're just
But they are moving at a very slow rpm, like 20 revolutions
per minute, or three per second.
No, it couldn't be three per second.
Three seconds per.
I can't even do that, sorry. Thanks, 15 years of math and
so slow and the type of So generators that would beis
in this turbine example need
running at 18 rpm, you need a gear box that will get you
up by a factor of 100 to get up to 1800 rpm.
That's typical generator speed. There are generators that
don't have gear boxes,
weird looking generators. They're made by the Germans.
Very effective, very reliable,
And to give you a perspective, weird looking though.
there's a turbine. on the far right,
most common turbine in this That's tcountry whiche of the
is the General Electric 1 1/2 megawatt machine and the
blades are about 77 meters
might be about 80 or 90 meters. in diameteYeah? the height
Are you also going to tell us about the blades that are
vertical and go around a
Bradt: I'll address it right now.?
They were popular in the 80's when there was a great deal
of expansion into renewable energies and we thought, oh my
goodness, we have to respond
let's research all kinds to the air oil embargo so
The benefit of the vertical axis, the most common one looks
like an egg beater, is called the Darrieus turbine,
the benefit of that is that you don't need to change
directions from your turbine
it'll take wind from any as the wind changes -
Okay? The downside of that turbine
is that they distort
Now if you remember from themselves essentially.
waves and nodes, you probably remember an experiment or
something your teacher did, possibly took a chain or a rope
and they spun it around and you could see the wave
on the rope.
rope like you're holding So there were points on the
in space and you're spinning it, the end of it, it's still
"woo, woo, woo," right? So, you've got this turbine
which is a huge shaft made
it's absolutely fixed in space of metal so it's flexible and
then it's doing this. Now to try to fix this
spot on top in space, they
They try to hold it in space. The problem is you've got all
that vibration going for years, the guy-wires are going
to loosen up and then the thing's going to fall apart.
So for big turbines,
installed them, basically went they got installed, the company
they were abandoned. broke trying to fix them and
used in small application like Now there are vertical turbines
They're easy to put up but putting up top of your house.
about such small forces, in that case, you're talking
the shaft so it's got way andtoo much metal so it canld
tolerate all that and last
Beyond that discussion, I don't talk about them because
in the utility, in the 100-megawatt scale
and the power grid scale, nobody uses them.
Every once in a while, someone
great new discovery! says, oh I made this
of a reinvention of the same And it's just kind
will have the same problems.
(laughs)
Okay, so, how does
First of all, the blade is the turbine work?
a propeller in an aircraft an air-foil, it is just like
It's an air-foil. It has a different shape
on one side than on the other and notice here that this
edge here on the bottom is kind of short and
this edge on the top is a little bit longer.
It's very subtle but there's
And then if we tilt this blade, see this dashed dot line here
going through the middle, we call that the cord.
If we point it a little bit up from the direction
the wind's going, we actually accentuate the differences
in distance that the
So, as wind is hitting that aair foil from the front,
the air molecules coming in that are just slightly above,
they have to go a longer
faster than the air molecules dthat are going underneath.o
As a result, you get a
above the wind and high pressure development of low pressure
So, essentially, this aboairfoil is sucked upwardsnd.
by the aero dynamic forces. Now those a bunch of arrows
that are in a kind
that's sort of how the, ofat each different point,s,
where the forces are pointing,
forces and add them together but we can take all those
which is going kind iof this direction and then
we break those two forces down into two components,
one that is in the direction
bad one - it's called drag - of the wind, that's the
perpendicular because it's lift, and then the good one is
off the ground. Now, let's take that airfoil
and put it on a spar, attach that spar to a shaft,
okay? So it's now like a wind turbine
blade and let's let it spin,
As this is moving forward in this circular arc here,
we have a artificial wind speed that just comes from the blade
moving through the air, right?
the wind coming. And we also have
as a vector and we get We add those two together
Now, would you notice that the resultant wind.
cord, the angle there, this resultant wind and the
is about, you know, roughly tabout the same as what
this one here called. So they're both the
angle of attack.
turbines have the ability to control the, what we call
the pitch of the blade
at the forces, the -- forces a little bit and we can get
particular power setting. So we're creating that,
those lift and drag forces -
that's perpendicular to nthe relative wind and it's
in this direction which is
We don't care about going sideways.
We have--we can take that and decompose it into two
directions, one that's
blade is spinning and one that's perpendicular to that.
So, this is what we call
That's the really good stuff, that's what--that is the force
that is a result of us sucking
Okay, this thrust--this is the energy out of the air.
Because what that's doing is structural engineer's nightmare.
you know, it's being pulled athis way by the torque
but it's being pushed backwards by the thrust.
They kind of have to make sure
down and strike the tower because then turbines fall over.
So they actually have to design these turbines
with advanced deposits and
they don't flex too much. Now, once we have the blades
on here and I've chosen to show a two-blader turbine,
not because that's the
because it's easy to draw. common turbine anymore but
you're spinning, we're going And as you're moving, as
into the nacelle on the shaft tand I want you to thinkg
of a topical to tip speed.
130 miles per hour, 150, We mentioned it
to be the rotational speed that tip speed is going
distance of the blade so so the 18 rpm times the
omega times r. in my equations that's
Okay, there's a few equations-- Othese are the last equations.
I'm going to explain to you,
through quickly. the rest I'm going to pass
again, kinetic energy - that's Back to high school physics
we learned that it's 1/2 times the energy of the flowing air -
So a bigger mass has more energy, a faster object has.
much more energy, right?
flow of the air, the flow of the mass is equal to its
density times its speed times its velocity times the area,
okay, so the turbine is going to spin in a circle and you've
got this pancake shaped piece of air coming through it
at any given second.
there's a little dot over it, Sover the m, that means the
change of mass in time -
If you drop that m dot into n, cool little Calculus thing.
now, so then that equation, okay sowhich is e dot second
is actually power.
between energy and power - You know the difference
to do some work, power is enehow much energy you needgy
to move in a given second.
we had that row? So, power, remember
that's the air density. Higher air density is good
and we had a v squared up in the first equation and a v
in the second equation so now we've got v cubed.
And we have an area, so if
we get more power. you make your turbine bigger,
place that has better wind If you site your turbine at a
much more power. as in faster wind, you get much,
eight times the power. In fact, twice the wind,
you know, a turbine is So now, the weakened state
to take all the energy out just not going to be able
it to useful work. of the wind and convert
coefficient of performance - cp. So we're going to define a
in Germany and he did his work Now, Professor Betz lived
of a movie--this makes me think of a movie in the 80's called
"Bill and Ted's Excellent Adventure"
and they're trying to figure
for their history test and so who is this guy named Socrates
and they come up with a answer
which(laughter)a dead dude.
He happened to be a dead Greek dude.
So who's Betz?
He happens to be the father Bof the knowledge of how to
make the aero dynamics
He showed through some Calculus that if you took the
air upstream and you slowed it
the speed, so say 9 meters down so that it was one-third
per second, if you did that, per second down to three meters
you could get out of it. you got the most possible energy
more, you'd actually get less If energy and I won't godown
into the derivation but basically the theoretical limit
he came up with, we've never
Now, on this chart, I'm btrying to show what you can%.
practically get out of a turbine and compare
two or three or four or five
So, on this chart, different turbine types.
coefficient of performance and on the vertical axis we have a
get out versus how much that isenergy is there. can I
And here, on the horizontal axis, I've got the variable
is tip-speed ratio. Remember I talked about
tip-speed, how fast the tip was going, it was a ratio
of how fast the tip speed is going verse how fast
the wind is going and I won't get into the mechanical and
aeronautical details as why that matters but it works out
that that is a significant
varies around that. So, up here on the dash line
that's the Betz limit.
Stynmet limit. This curved line here is the
Well, he's another Who's Stynmet?
He came up with figuring German dead dude.
energy was lost outfrom weight rotation.uch
But I won't get into those details.
(inaudible)
You're right, he was a dead American dude.
So, now looking at the various
we have here, here's the different turbine types
about, here's the Western American wind grows, about
45 million of these got built between 1850 and 1950
and installed.
of for aesthetics. They're mostly now just sort
very early ones, the The original turbines or the
in the 17th century - that's there, and can anyone
tell me why the three-bladed
chart, why everyone's building turbine won, looking at this
It gets the best energy harvest. three-bladed turbines?
that can achieve as high There's no other turbine
And it shows here that it gets as it can get.
what is that, maybe 47% and I'm sure every wind turbine
manufacturer salesman will tell you, oh we do that one better!
But in fact, very rarely can
Just, you lose energy from bugs tthat have smashed themselves
on your surface and dirt
there's all kinds of things that are working against you
at getting that work out. That's about what they can get -
a little less than half of the energy.
Okay, so the electrical type
to ask you to let the slides and this is where I'm going
kind of go super geeked out wwith some of the slidesdo
and I'll just kind
So we're going to talk of talk past them.
of generators that matter - a synchronous generator and
an induction generator and
the types of wind turbines - then we're going to talk about
based on speed control. thWe categorize themem
on speed control. Okay, so the synchronous machine
- this machine generates 99.95% of all the electricity that's
ever been manufactured. This is what is running in
hall plants, nukes, gas fire, hydro, everything you can
think of that are big power plants and including
some wind turbines. It is simply a big
electromagnet - it spins and
on the outside - they see ythese magnetic fields whirring
past them and voilą! Electricity comes out.
And there are three conductor sets, there's
A here, B here, and C here. And because they're
separated by 120 degrees
we get three different phases of electricity and that's
what we're seeing here. We've got the sign waves
and you get three of them.
only get one of those phases Now in your home, you get--you
power company runs the line - it's a three phase line -
into the neighborhood and then splits one this way,
that way and that way to go to different houses.
So you only get single phase
Businesses almost always get in your home.
big motors and stuff. Okay, I'm going to skip this
because I don't want you
but there's a lot of math toinvolved and this is kind ofn
why electrical engineers
Same with this one. studOkay, sorry.th.
There we go.
is that any machine that has What I want to show with this
and electricity can do both. a connection between torque
it can generate electricity. If you run it in one mode,
goes in, electricity goes out. Generation is just torque
You put electricity in and Or it can motor.
And there are ways to control how much you're getting in
and out based on that electromagnet, controlling
that electromagnet, being more magnetic or less or by
how you connect it to the grid. There are ways to get
more power out of it. And that goes back to when
I was talking about the power system that we control
the power to keep it stable,
synchronous machines often. There are other methods too.
Now, the other machine that exists is the induction machine.
This is the machine Nikolas Teslay invented
and I said 99.95% of
synchronous machines. el90 something percent ofby
all motors in the world are this machine.
They're simple, they're rugged, they're built
like a Timex watch if you remember that commercial
- it takes a lickin'
You can beat the hell out of and keeps on tickin'.
They are a little more them and they'll keep running.
they're a little more--harder dto understand in termsd
of the theory.
run is what good's about them. But you plug them in and they
very first wind turbines And I'll point out that the
And what was weird about that weris that nothing else wass.
generating power
And often what they have is instead of an electromagnetic.
on the rotor, they have this cage that we call a
squirrel cage and to me,
to have as a kid for my gerbil it looks like the cage I used
the term squirrel cage and but the industry has selected
all the rotor is. So it's really simple.
Going past, this is just to tell you that the induction
machine can be a rotor
So, comparing the different machine types - I talked to
you about the synchronous machine and the induction
machine - the other--the
machine in the middle is called a permanent magnet machine.
It's a synchronous machine, you don't need an electromagnet,
it has magnets and it's becoming very popular because
it can be really small and
and they're even better than the induction machine.
Although there are some that
I'd taken a lickin' and wokeep on tickin'.e,
In fact, they are what are
That they're all that right now. in hybrid cars.
like I said the very first one So the third type of turbine,
got blades, goes through a is very simple - it's--you've
generator, electricity goes gearout onto the grid.tion
Now, the blades may be able to pitch a little bit
for control - all they can do is basically control so that
the turbine is no longer
it is spinning. They can't actually control
their speed because of the
to--the generator they're motor tconnected to.onnected
It is fixed.
that the electrical grid It has to run at the speed
Remember the sixty hertz has is running at.
to be spinning at the tsame speed all the time.
And so then there are some other
that we might install, accoutrements of equipment
to help with startup--I'm sorry, including capacitor banks
with the current and capacitor banks to help
into those details. So the type two wind turbine,
same machine as we saw before,
at the currents that are however we can actually get
that's moving and we can add in that rotor, the part
And that changes the extra little resistors in.
changing the speed and we can only change the speed by 10%.t
We can make it go 10% faster, which, remember that curve
that showed all the turbines
they had this shape like this - there's an optimum tip speed
ratio that you want to be at
increases, you'd like to spin so that a little faster.d speed
So this is the beginnings of
speed a little bit. Now the type three turbine,
this is currently the state of the art.
We've now taken, where that resistors were, and we've
been kind of adjusting--
on the rotor and we're messing with the currents
Basically these things putting in a power supply.
the bottom- they're basically like a variable speed drive
that might run fans in a
But what it's doing is it's buitaking power off the gridhat.
and circulating it
technical term is to funk with the magnetics in the
machine and adjust
It also allows you because where the voltage is going.
the voltage, you can adjust the frequency, you can make
the machine go slower or faster,
a bunch faster. a Theoretically,nd
plus to minus 50% speed difference, often the
manufacturers only build it with a plus to minus 30%
or thereabouts. So, as your wind speed changes,
you can really try to optimize
rotational speed. itWhen it's operatingent
above synchronous speed,
What will happen is power will come out of the machine,
out of the starter, it will come out this way and power
will also come out--a little power will come
out of the rotor. And when it does that, you get
a net power, you know - a great deal more.
That makes sense -
spinning, lots of power. high wind speed, high
below synchronous speed, you When you're operating
of the power that's coming actually have to take some
primary terminals and you have out of the machine--
And the reason is to basically to circulate it back.
it doesn't cause a collapse kor anything like that.
Now, in net, you get less power out but you're
getting power out.
able to get it, not only can Whereas other machines would be
you can get power out yoat wind speeds that otherds,
turbines cannot.
generator self produced? >> Isn't the induction generator
But if you bring slipperings >> Bradt: They are.
rotors out, you can connect tthese power supply devicese
- they're called inverters
(inaudible)it.
Well they can self induce from the stater side or you
can control what's on the rotor from the rotor side.
You have both effects happening at the same time.
Okay, the type four, the kind of the last step that's been
taken in development is you take essentially those two
power supplies and you put the
the grid on the other side. The result is, is that the
machine puts out its power, it goes through one of the
power converters, and you'll
converters, there's this notice between the two power
that's a capacitor - little device here -
So this AC here from the it'll hold a DC voltage.
and then this converter machputs it back to AC.to DC
So you can control this converter to always give you
exactly sixty hertz, okay?
what the frequency is here Now, over here, we don't care
it to DC anyways and then breinvert it back to 60 hertz.t
So we can run that machine
variation now becomes at anvery, very wide.speed
It becomes as big as
economic considerations aside. you want to build it,
is that you can whack One ofthat gear box.efits
Gear boxes - heavy, it's
considered the biggest problem expensive, and it's often
It breaks a lot and when it breaks, they're big and heavy
and it's hard to fix. So, there are some manufacturers
of turbines that have decided to go that route and they
have what I described as
the (inaudible)d turbines.
Well typically, you're
Can you repeat the question?
Bradt: Oh okay. He was asking to compare the efficiency
overall of a machine that has a gear box and a
conventional method of
versus a machine that you putwhack the gear box andut
you push everything through these converters.
So, the first approach, which is a gear box,
you're going to lose 15 to 20%
and you have humongous of your energy immediately
of all that waste heat. cooMechanical engineersrid
are just not as good as electrical engineers, so.
(laughter)
Then you're going to have about 98% of efficiency
on your motor, on your generator
to have about 95% efficiency. So, 20% loss and then 2% lossg
and then 5% loss, so you're probably coming out -
what's the math? -
If you whack the gear box, about 80% of the power.
a big heat source but you're of course, you're removing
power through the silicon. also pushing a lot more
In general you're going to get more through this.
But here's the thing, it kind of doesn't matter if you're
in a good wind zone what your efficiency is so it's not---
that's not the reason why people
They would decide based on would decide to use it.
Am I going to have to replace my silicon parts more often
or my gear box? Okay, this is an example
of one of those.
called "Clipper," This California company.Iowa,
They have a drive train where it has one slow shaft and it
actually has four high speed
different generators on there. shafts so they have four
one of the generators blows, And the benefit of that is if
quick, run a guy up the tower tor a gal up the tower, pully
the one off, toss it down so
Put the thing back in service with three of them and run
it the graded operation.
interesting design This is kind of an
Here's another one: remember I said weird?
This is weird,
Instead of it looking sleek and narrow than this cell,
so the wind can get around it,
generator down here bhas no gear box, it's notis
going to spin at 1800 rpm,
so it has to be huge, it has it's going to spin at 18, and
And, as a result, then this cell to be like a huge pancake.
It is kind of odd looking is but they have theirape.
efficiency advantages and their reliability issues.
Okay, so I'm going to talk
energy production. about capacity and
about it, that's the nameplate So capacity, if you think
So, a GE one and a half wind turbine has a capacity
of one and a half megawatts.
one and a half million watts. If it runs continuously like
say a nuclear power plant,
1,000 megawatts, you're going to get a full capacity factor.
Now, using this one and a half
8,760 hours in a year, except leap years, and if you multiply
that out, you could get out of that machine 13,000
something megawatt hours
That's a lot of power. or 13 gigawatt hours.
The wind doesn't blow all the time and it doesn't blow fast
enough all the time.
the 13 gigawatts. SoSo let's look at whatet
a turbine can produce.
This is the kind of the performance curve and I want
to point out three different
First one is the cut-in, wind speeds of significance.
which is typically about that means below the cut-in,
you get no power out. Once you get above three,
you start getting some power
You're not getting but you don't get very much.
The next speed is the rate-in, one and a half megawatts.
Once you get to that, tyou got full power..
And to stay at full power without like overheating the
machine, the blades start pitching and spilling wind
as you get too fast,
of the energy go by because they don't have the electric--
magnetic capability to convert all that.
And then the final speed is the cut-out speed,
this is usually about 25 meters per second which
is about--it's above 60 miles per hour and that's gale force
wind at that point. So you have very severe storms
Turbines shut down, furls its blade so it can't
catch any of the wind that is coming and then sometimes
if it's really extended time
okay? And just stay out of the wind
and just try to stand up. They can usually withstand
quite high winds, they cannot,
can withstand a direct hit there's no turbine built that
But there are turbines that are considered hurricane safe.
Not category five but like
Okay, so capacity factor maybe up to three, I think.
annual energy produced - is the ratio of
going to get that 13 gigawatt hours because we're on that
slope some of the time, we're not always getting
the full-out. And so, okay, capacity factor
depends mostly on the wind
in North Dakota, resource - you locate
If you locate in Georgia, you have terrible wind, okay?
You're going to have very low capacity factor.
It can be enhanced by selecting the particular
turbine that may do a little better than the others.
So, let's consider a contrived
that the assessment people do chart,for a one and amething
half megawatt turbine.
average annual wind speed Andis down here, there's a,ur
you know, data to tell you
to get out per year. how much energy you're going
I just picked a spot So let's do this location and
that had an average in Wisspeed of seven.m spot,
Now at seven I'm going to get,
- it's a little hard to see - ifit's 3,500 megawatt hours,rt
so 3.5 gigawatt hours.
you get 26, 26% and that's So divide 3,500 by 13,000,
You can get about 26% capacity. And if you go West from here,
you can get better. I've heard claims of 45.
Some people made claims of 50%
proven to me that that's but I have yet to have that
Okay, so, wind sight assessment, actually occurred.
assessment of how much energy howe're going to producehe
in a year?
is you go out and put a bunch of anemometers - those are
those cup things that whirl around and tell you the speed.
You can also do it with sound.
big huge horn, it bellows, They have sodar which is a
for the sound to be reflected andand it can use Doppler.ens
Same stuff that the cops use
with their radar. They're using with light.
You can also do a light detection so they shoot
lasers up and detect
Anyways, you detect for one, what the speed is.
all the wind over those time two years and you get--you get
How much of the time during athat year are you at zero?.
How much are you at one?
How much are you at 25? HoAnd we just create ao?
distribution chart here, okay?
there at nine meters per second. So I'm going to pick an example
at this location--we're there at nine meters per second,
just a little bit less than 5%
So that's 417 hours per year of the time, 4.76% of the time.
There's the curve of a particular turbine.
This is not the GE 1.5, it happens to be a Vestus V47,
an older turbine which
so .66 instead of 1.5. produce 660 kilowatts,
per wind speed. You notice there's quite a few
wind speeds in the beginning
Now, at nine meters per second, it's producing 362 out of 660
possible kilowatts and so then
square with the middle black if we multiply the top black
black square, okay? So at nine meters per second
at this location with that
you're going to get 150, 151 wind speed profile,
You do that for every wind kilowatt hours per year.
bump, you add them all up, speed, you go bump, bump,
much energy you should and you get how much wind--how
That is the key point of a wind site assessment
that's done for two or three
The banks do not want you to ask for money until you can
tell them and prove it that you're going to get
that much energy. And because they have
all the money, they control what gets built.
(laughter)
Okay, so here are a few little resources, I wanted
to just make a plug for my
courses for people in industry, othree and four day coursest
for people to spin up in an industry and it's the
Department of Engineering Professional Development.
I'll leave you with that. Okay, so this is the tour
I was talking about.
of the balance of plant. We're going to have a picture
what's the balance of plant? The balance of plant--
not the turbine. It's everything that's
engineering drawing with a lot of lines on it.
Every little box, this is a pretty big wind farm,
this is schematic diagram.
here with the text - Every little box
there's three together, therthat's a turbine.one,
That's a single turbine.
run in between them - da da da da - and so forth,
that's the collector, the feeder, that's where
all the electricty
And then each group of turbines come- there's a group,er.
there's a group, and so on
we call home run feeders - all make their way on what
into circuit breakers. back to substation and
bunched into little groups So they get laid out and
Now, that's really neat based and they're all kindated.
of lined up in lines. They're not actually
laid out like that. That's the physical plan
of how they'd be laid out.
has been partly been And the way they're laid out
best wind, and where's where the ridges, where's the
to put turbines on his site because he's going to getu
10 grand a year and where's Farmer Smith that
doesn't like wind turbines. So you've got to work around it.
So I think here is lucky
obstinate Farmer Smith is basically how it comes out.
So, general layout
the turbine and up inside the turbine, you have this is
a symbol for generator and
and protection, you know, all the equipment that's ups
in the tower. Then you have the cables
running down the tower, then you have a transformer
that's usually just outside the turbine on the floor--
on the ground, I'm sorry, that then connects to the
collector system
Now it is possible that the pad-mounted transformer will
be up above in the nacelle
So that's what the turbine but this is typical.
If you ever get to step-up transformer looks like.
here's the entranceway and go to a wind farm, you'll see
almost always green, then there's this--they're
That's what takes the voltages, thyou know, in GE's case,t.
from 575 volts up to 34,000 volts is what we generally
collect at. It's possible to have a
transformer located up
you have really heavy parts up at the front of the nacelle,
it's a good idea to have
in the back of the nacelle. The transformer's nothing but
a big hunk of steel wrapped with some heavy copper.
Okay, so then it makes it down, it's gone through the
transformer and it drops
the cables running away intfrom a turbine towardsare
their next site.
a trench, four feet deep, that actually doesn't look
four feet but I think they
They'll put it in, have lowered the soil.
a very special backfill and then they'll reclaim
the land - they'll put more on it so then you can plant
grass and all that kind of stuff back on there.
Gets laid out on the trench and there's guidelines as
to how that's done, powers
this road to the next site -- this is more than I wanted
to give you but that's what a conductor looks like,
you've got this outer jacket, you've got some protection,
the insulation to make sure that the 34,000 volts doesn't
hurt, harm anyone.
the aluminum or sometimes copper conductor in the middle.
Okay, occasionally we will
the so-called telephone pole type lines.
It's uncommon, farmers don't
because they have to run their, wayou know, their tractorsd
around it.
get the landscape like There are times when you
of granite or something like creek crossings or a lot
to go underground. that where it's just impractical
or something like that. YBut they'll just pop up outng
of the ground and they'll run overhead, usually for a
very short distance,
they prefer not to use this. for aesthetic reasons,
And then you've made it all the way back, you've gone past
all these various turbines
all the power together and collected all the current,
When the cable pops up and and you go into the substation.
cables are coming out of it's hard to see but the
a conduit right here and a pipe right here out of
There's one, there's two, thand there's three and then.
the conductors go up to a bus and that's how the electricity
kind of gets distributed
And that then pops down into these four gray boxes,
there's a fifth one also, that are called
the circuit breakers. A circuit breaker is a device
that if current is flowing
because you have someone and there's way too much of it
caterpillar and the sparking, narking, and there's 50,000
ants when there should be like 400, the circuit breaker
senses that and, poo!, trips. You hear a big bang, bang!
And but it stops the current. The additional breaker is
to protect the next device, I'll show you, which is
the transformer,
We had one that went from 575 to 35 KV, this transformer
then goes 35 KV up to 345.
moved from here through this transformer and out onto
the much higher voltage lines,
and it can make its way to other substations and
into your home. And often there are other
devices that get put
control the power flow, icontrol the voltage there.
We call react developments, capacitors, and the other
device is called a reactor. And then there's what
a capacitor bank
And here's what reactors looks like is boxes.
like donuts stacked one lookon top of another.ally
And then there are special, expensive, but very capable
elements that work like the converters and turbine
to push the voltage around. And I bring those up because
the two biggest competitors for that are both
Wisconsin companies.
Essence C Electric which is in Franklin, a suburb of
Milwaukee, and the other one
which is here in Middleton is American Superconductor
So, that's--this is one of the examples where
wind installations generate a lot of work, particularly
locally here in Wisconsin.
You've been asking them Sthroughout which is greats?
but any...yeah? >> Lots of them are stocked.
It looks to me like 25% of them are stocked.
What's going on there?
as to what exactly is going >>on but what could go on withn
that is that there could be a problem with one of the feeders
or they could have to work
of those breakers. on due maintenance on one
they all get brought in Soin their different groups?ow
Maybe they're working on that feeder and they had to drop
it out and if--there's
they don't let nowhere for the energy to go,
If you ever see a farm that--a the turbines turn.
and it's a really blustery day, there should be a lot of energy,
and all the turbines are off, either the wind farm hasn't
been commissioned yet - it just got built - or that
main power transformer, the one place the power gets up
onto the grid,
That's happened before - that's out of service.
right at the wind farm it happened at the--it happened
that's right near shorthe wildlife refuge.ing
And people were driving by
you put up this thing, for several weeks going,
why aren't they turning? it was super controversial,
with their transformer. So there was nowhere for any
of the energy to go so
What is the role of tso-called rare minerals?
in the action of the turbine? There's a line about Chinese
virtual monopoly on the mining of such minerals.
That is a really good issue.
four turbines, particularly the most advanced ones that
had the most speed control, and also for the motors that
are used in hybrid cars for example, it really became
valuable to use the permanent magnet machines.
Let me give you a little history.
So, permanent magnets were kind of starting to be used
in the '50's with some
They didn't work that great and they're pretty expensive
but then it got a new material
Worked a little better, still pretty expensive.
Then General Electric and also
called Sumitomo got--dually got patents in 1983 for
something called
which is a mouthful. neodymium iron boron
we just call it neo. In the industry,
both in the magnetic And they - it was much better,
that it was--it could heat up. capabilities and the fact
quite a lot for it even though And they started charging
the previous materials because it was less expensive than
and they would trade off they knew it was more valuable
making much more profit. selling less of it for
rescue and they're doing the Well, the Chinese came to the
call it coming to the rescue. saThey took the material andt
they didn't care that these two companies happened to have
a patent on the stuff and they just started selling it
on the market at much lower prices and they crashed
the price about 80% so then it became really affordable
and everybody started using it
valuable this stuff was and now the Chinese have sort of
recognized that, we could sell
of the ground or we could yotake it out of the ground,t
we could smelt it,
we could build motors with it we c- wait, we could build auct,
full wind turbine for you and we could capture all that
value at and all that labor.
for three million dollars than the ore that would go into
it a turbine for, you know, handfuls of thousands.
And that's what's going on. That's essentially the
history of it.
Where is it going from now? There's a political side
to that that I can't answer.
designers of this sort of equipment, both the hybrid
vehicles and the turbine
They don't need to use permanent generators are concerned.
machines but it will take a mabig step in innovationser
to make other types of machines work as well.
So, that work is beginning. So, yeah.
You were next, sorry. >> There's been a certain amount
of concern about infrasound generated by these
wind turbines.
that there is something called Some people have even claimed
which affects the human body vibroacoustic syndrome
long periods of time. What's the status of that and
are there design attempts that are made to try and
avoid this problem? >> Okay, preface to my answer:
I'm not a physician and I am
read and I'll also provide parodying reports that I've
of information is all the from the American Windrce
Energy Association, who is a proponent of wind.
But what is claimed to be independent analyses by both
sound engineers and doctors working together is that the
final conclusion when you get through that VBAS syndrome
and so forth is that, first off,
percent of the human population that's very sensitive to noise.
And there are about that same percentage of people
who are sensitive to wind turbine noise.
So the conclusion I'd draw is if you're really sensitive
to noise, you're going
to wind turbine noise, to be really sensitive
or traffic, or whatever. or train noise,
I do understand the AAmerican Medical Association
or whatever bodies exist
existence of a syndrome so to formally recognize the
have roundly refuted it. the diagnosis can be made
doctor in New York, I can't remember her name, that's it.
Dr. Nina. And she's got all kinds
of what I am told by
is whack-job science.
(laughter)
That's, I think that's a
if the medical community uses tthat but it's just--she'sow
roundly, I don't know if
believed in her science. she's discredited, just not
to lawyers than other physicians She spends more time talking
Yes? is what I understand.
for this system compared >> What is the comparative cost
Oh boy. to anotheOkay, cost. as coal?
Well there's two ways to look at that and that is installed
cost - what's it cost to build it?
and cost of energy, okay? Installed cost for wind turbines
varies around, at one point,
per kilowatt or $1,000,000 it was as low as $1,000
about the scale of a turbine. Coal right now, and it has gone
up as high as $3,000, and that was really in 2007
and '08 when there was a
concrete was more expensive, real commodities bubble and
copper was way more expensive. steel was more expensive, and
being quoted at $5,000 Coal right now is
So, coal is very expensive for installed capacity.
A lot of that has to do with permits and a lot
of the environmental, I don't want to call it
remediation, but what you have
Cost of energy, I don't mean to do with the flu gas, okay.
And you almost can't to pun, but coal is dirt cheap.
I mean, nuclear can beat coal because uranium is even more
dirt cheap, I think you'd call that rock cheap.
(laughter)
But you know wind can,
costs is how much you spend and how much can you get out.
The cost of energy for one and
say a farm of 100 of those a half megawatt turbine or
lot higher than here in Wisconsin could be a whole
in North Dakota, because in Wisconsin than it would be
energy out of it you're getting maybe 80% more
One of the things about renewables is that -
this is a little hyperbole -
not all of it - there's a but allittle bit of it, front,
operation maintenance costs for spare parts and having guys
climb up--or gals, climb up and torque the bolts every,
you know, year. Stuff like that.
Respond to trouble. But basically once you've
spent the money up front, you're paying your debt service
and so forth. It, you know, it's free energy
after that so really a tradeoff on how you finance things.
I'm not sure who's next.
I'll get to you next, okay. >> We've got about ten years
of experience now with wind turbines.
Do we have any idea how long
estimated lifetime, th40 years, 60 years?t's
The kind of the warranty
manufacturers is somewhere claim by most of the turbine
We actually have 30 years in of experience with windrs.
turbines, not the megawatt--
but I mean I've been up in multi-megawatt scale,
and I actually went up to the wind farm there, because I'm
kind of a wind geek, climbed
and they're up grinding away the mountain, saw them,
after 30 years. Some of them aren't but
they're lasting quite a while.
the designs are considerably And I have to say, I think that
25 years is a very safe bet evand perhaps longer. Yes?ay
I noticed a wind farm that's
in Illinois, that's between on the -- and 39.way
Okay?
(inaudible)
I don't know. I know it has Vestus turbines
but I don't know who owns it. Sorry. There was someone back
there, I said you'd get next. There you go, I'm sorry.
It's sort of a financial
In the nuclear power plants, motivation question.
has no property taxes, the township around the plants
There's a story about a Danish island some years ago
that had resistance with
folks all had a financial turbibenefit from it.nding
Is there a movement or a
to rather just have that farmer perceived income than
everyone in that area receive income from it?
Well, let me summarize. The question is:
does money make problems go away?
(laughter)
Here in the United States,
our economy than in Europe we have less planning to
of socialized benefit and socialized cost is more common
there whereas--you know,
different countries in terms this country is really 50
developers here and utilities will do whatever they can get,
you know, if we can get Farmer Brown to take it and
Farmer Smith doesn't like it
trouble, then he but he's not going to cause
Now the township will get payment in lieu of taxes
because there is property and they do claim to have the
authority to take tax on property.
So they do get some revenue in lieu of property taxes,
that happens. I'm not sure how I could
compare it--wind farm to
I could tell you that the revenue stream on a 1,000
megawatt power plant--nuclear power plant is going to be
enormously bigger than
that's been built yet. on any wind farm
to throw around essentially. So there's more money
non-answer, sorry. So that's my kind of answer,
How noisy would one of these Please.
Well, you wouldn't things be in my backyard?
in your backyard because even though it's very, very rare
for them to fall down,
500 feet tall and with the they fall, they're, you know,
angle and wind and stuff, they might hit 750 feet away.
So you'd want it a little ways
Having said that, we know that sound is
inverse square so the farther you are--double the distance,
one-fourth the sound pressure.
requirements at people's homes So, typical sound level
That's actually softer is 50 decibels, sometimes 55.
However, it seems that the than my voice right now.
technical issue, although I'm not an expert, is really
coming into somewhat of the frequencies of the sound but
the tones of the sound, not just the sound pressure,
not just the power
And we've worked very hard of this sound.
- somebody asked earlier are to make the power of this sound
generators doing anything turbineto mitigate that? turbine
And the answer is yes.
it so that you spin the blades There are ways of controlling
given wind and you make it a little bit slower in a
giving up energy. So it's possible to program
a turbine to - and you
as the turbines are working. can do it on the fly,
reducing mode in the winter, You might change to a sound
because the sound travels easier or you might do it
at one sight where there's
that are really upset. a couple of homeowners
I'll make them happy, I'll spill energy, and make less
wind and hope that that helps.
with turbine manufacturers. Also, I will say that part
of the siting prior to doing
how much wind can you get but then all the impact issues.
What's the visual impact? What's the sound impact,
you know? There's the birds thing -
I call it the birds non-issue.
there someone else back here? But gI'm sorry, it was--was
you and then you. >> I read that in Sunday's
paper, that the Governor
between towers be quadrupled is proposing that the distance
What's the reason fromfor increasing distance?is.
Well, actually the proposal is to--well, increasing the
distance between turbines is not what's being proposed.
The distance between turbines is set by the planners that
know how packed they can
interfere with each other. put it before they start to
is to--is the setback from a property line.
So, if we're going to build on your property and your
neighbor is over here and there's a line right here,
we have to be 1800 feet away, which is quite a bit more
than it used to be. I don't have any technical
reason why that should happen.
Two part question. Rob and then you?
reports about climate change One is there's been some recent
wind speed and I'm curious and changes in worldwide
that in terms of the impact if theof the built base?ng on
The other question, unrelated,
moved to wind-tipped vortices is aialmost universally, much
even small, small airjet
And I'm curious, I have yet to see one of these guys
with those and I'm wondering
Second part first. why that isn't beneficial.
on small turbines. It has happened,
it, you know, it adds some They have tried doing that and
The reason it isn't happening on a large scale on all turbines
is primarily a cost issue.
is really built around making sure that that thrust force
doesn't force the blade backwards so that it
hits the tower. That's how all the real
structure is being built now. If you add that tip out there,
you really change some
You can improve efficiency but, you know, it's a tradeoff.
The first part was when people
they're looking at two years are doing wind assessments,
They're predicting into the of dfuture for 30 yearsast.
for the benefit of a bank who cares only, really,
about the first seven years.
in a project by project, So, I don't think, you know,
a wind farm project, I don't you know, I'm talking about
I think the climate scientists think that's being considered.
And I don't mean to amake light of that at all.
I just, you know, pragmatically,
that's not something that you can really--what is this
climate change going
or not and the answer to affis who knows? years
There was over here, sorry. And then you're next.
What's the maximum height you can get a tower and
can you have more than one blade apart?
Maximum height of a tower?
How(laughter)y you got?
As towers get higher, they end up having to be
a considerably stronger which means thicker.
And so the second part of your
blades on the top? question is can you put two
put a blade, put a tower You know, like put a tower,
And it's never been done and I and another one.
know we already have a system think ithat works well.se you
You know, put one up, put one up, put one up.
The other thing is
really well known to--really I don't think that it's
would be of two blades well known what the dynamics
You've got this tower that's swinging at once.
you know, and the wind, beso it's got this going on.d,
And then you got this,
to twist it and maybe this gmoving this way.trying
Now add another one and it just gets more complex.
I'm not saying it can't be done,
looked at that as a barrier bthat's kind of not yete
worth producing--not yet
And frankly, in the places worth pursuing.
red that I showed - thayou got a lot of land.hat
If you want more turbines,
the next farmer over. Or if you can be lucky and
get in West Texas you talk
to a million acres.as
(laughter)
(inaudible)
How many turbines would you need to satisfy
all the Americans demand? I don't really know and it
depends on what turbines there
that while turbines are good would be but I can tell you
clean energy and then, in that they're creating
creating jobs locally and all that, there are some
electrical characteristics
presents challenges of tto the grid control.em--
So the kind of conventional wisdom is that maybe we can
get to 20% wind.
it'll be a challenge to get Qto 10% wind but much above
the 20% wind and you go into wild power swings.
This happens in Denmark when
at 150% wind. tThey're producing more
power than they use.
their power systems survive The onis Germany. they,
So they're just pumping out lots of power to Germany
and Germany is providing the
so if Denmark were cut off, suit would go in that stated,
and all the lights would go out - and on, nothing on, and then
out, you know, it'd be kind of crazy.
Where was the next one, I said. You, thanks.
Is there a significant
the two bladed turbine and sound difference between
Yes. Two blades louder. And the very few number of
one bladed turbines that got
were really, really loud and built, some Italian company,
is spinning so much faster. it'Okay, one more question.tip
I saw this hand over here and we can talk afterwards
if you want.
If there is enough wind to make the turbine go around,
do they sometimes shut them down
and then use energy to get them beup to speed again or is thatd
only some types of turbines?
that required power to start. Turbines aren't manufactured
now, that I know of,
When wind speeds drop off, that do that.
they coast to a stop, tthey sit there,n,
they turn their blade into
efficient angle so that they the most aero dynamically
They will--they essentially can cwon't start moving.lable.
They can't overcome the torque
until they get up thatto that three or foury has
meters per second.
being driven by the wind - They slowly spin up, they're
a motor and then the system thsynchronizes and clunk,by
the circuit breaker closes
Only a little bit, and power's coming out.
I'm told that we're out of time and that's
all the questions.
a little while longer if you want to talk.
(applause)