Wind Turbine Technology
Wind Turbine
Technology
Context
Since 1968 the world population has increased from 3.5 billion
to over 7 billion. The majority of people live in undeveloped or
developing countries. With increasing development comes an
increasing demand for energy. There is however growing
realisation that the use of fossil fuels has had undesirable
consequences and that we need to reduce CO2 emissions.
Alternative and more sustainable sources of energy will be
increasingly required to meet agreed targets.
Worldwide, solar and wind power are the most rapidly growing alternative
energy sources. The chart shows the rapid growth in installed wind power
in the past decade or so.
With
Rotor blade
Since
minut
to 180
drive
gener
gearb
parts,
and s
have
coils a
600) a
diame
magn
Nacelle
Hub
Tower
A 3 megawatt direct drive wind turbine
How does a generator work?
In 1831 Michael Faraday discovered the key to the generation of electricity.
He found that a voltage is produced between the ends of a conductor when it
is moved across a magnetic field. If the conductor is formed into a coil then
the induced voltage is proportionately greater, depending on the number of
turns. Also, the faster the conductor cuts across the magnetic field, the
greater the voltage. In practice multiple coils and magnets are used (e.g. 12).
Wind power has been the most rapidly growing form of energy in Ireland
over the past ten years; installed capacity has risen from about 600 MW
(in 2004) to 2190 MW (in 2014). Wind power is generally greatest in Ireland
during winter when the demand is highest − in contrast to solar power.
Since wind is very variable the actual capacity is, on average, about 25% of
installed capacity. So although wind power sometimes accounts for over
50% of the country’s immediate electricity needs (roughly 3000 MW ± 1400
MW), wind energy currently accounts for roughly 20% of our total annual
electricity (18% in 2013) and about 3.5% of our total annual energy use.
The target set by Government is for 40% of the country’s electricity to be
derived from renewable resources by 2020.
Background
In 1800 Volta invented the battery and it was an immediate sensation.
Within months several discoveries were made: the heating effect of electric
current, electrolysis and electroplating. However the discovery of the
magnetic effect of an electric current was not made until 1820. The first
practical electric motors were made in the 1830s but they still depended
on batteries.
What was needed was a practical dynamo, but that development took
another thirty years (1866). Further improvements in dynamos and
alternators led to the first commercial electricity distribution systems (1879)
and electric public lighting (1880s).
For over 1000 years people have been using wind power to grind grain.
Its application to the generation of electricity came in 1887 when the Scottish
engineer, James Blyth, built a wind-powered battery charger.
rotating
armature
North pole
of magnet
South pole
of magnet
Conc
enviro
neody
have
altern
Syn
The f
voltag
to the
as tho
peak
1. Sy
th
wi
2. A
th
ch
fre
ov
slip ring
Whe
a.c. out
carbon
brush
Different configurations
1. The coils (called armature coils) rotate in a fixed magnetic field. This is
the preferred configuration when the magnets are heavy.
2. The coils are arranged in a fixed ring or annulus outside the rotating
magnets; the magnets need to be light and strong (e.g. neodymium
magnets).
3. In place of permanent magnets, coils can be used to produce the
magnetic field. These field coils may be fixed or rotating; they use a
small fraction of the electricity that is generated — much less than 1%.
Slip rings provide electrical contact with the rotating coils, whether field
coils or armature coils.
Air m
of air
kilogr
of a w
of ove
If, for
air mo
This h
7.8 M
If the
down
The tu
powe
of the
are ge
Betz’s
availa
turbine
ricity.
when it
il then
mber of
e
.g. 12).
his is
ng
m
a
1%.
r field
Wind Turbine Technology
With or without gears
Since large wind turbines spin relatively slowly (10 to 20 revolutions per
minute) gearboxes are used to increase the rotation speed of the generator
to 1800 rpm. More recent direct
drive systems use low speed
generators that do not need a
gearbox; they have fewer moving
parts, require less maintenance
and so are more reliable. They
have a large number of smaller
coils and magnetic poles (e.g.
600) and so tend to have a large
diameter; some use permanent
magnets but most use field coils.
Concerns about the
environmental impact of
neodymium mining in China
have boosted the search for
alternative direct drive systems.
The nacelle of a geared generator
Synchronous and asynchronous generators
The frequency of the mains electricity in Europe is 50 Hz. The typical output
voltage of a wind turbine is about 690 volts, AC but it may not be connected
to the national grid unless its voltage, frequency and phase are the same
as those of the grid. (Alternating voltages are in phase if they reach their
peak at the same instant.) There are two ways in which this can be achieved.
1. Synchronous generation: The turbine has a fixed speed of rotation so
that the output voltage is synchronised with that of the grid. Many early
wind turbines operated in this way.
Siemens has been a major driver of innovation in the
wind power industry since 1980 when wind turbine
technology was still in its infancy.
Technology has changed with the times, but Siemens’
commitment to providing its customers with proven wind
turbine solutions remains the same.
The combination of robust and reliable turbines, highly
efficient solutions for power transmission and
distribution, and a deep understanding of the entire
energy market ensures that Siemens will continue to
take the wind power industry to new levels.
Long-lasting customer relationships – based on a track
record of successful, reliable project deliveries – provide
a sound, sustainable, and profitable investment. Drawing
on more than 30 years of experience in the wind power
industry, a strong focus on renewables, and a global
network of highly skilled and trained employees,
Siemens has proven itself to be a trustworthy and
reliable business partner and will continue to do so in
the future.
2. Asynchronous generation: The turbine’s speed of rotation varies with
the wind speed to maximise the power output. The output is then
changed to direct current (DC) and then back to AC at the voltage and
frequency of the grid. Although this involves some conversion loses, the
overall efficiency is greater.
With an increasing number of turbines being installed at
inland, coastal, and offshore sites, reliability and
best-in-class maintenance under challenging conditions
are essential for optimising the return on investment
throughout a project’s lifecycle.
Where does the energy come from?
Over the past 30 years, Siemens has accumulated
millions of hours of service experience. Drawing on this
substantial knowledge, the company has established a
flexible range of service solutions that are designed to
optimise the output of wind turbines.
Air may seem weightless but in fact it has significant mass. A cubic metre
of air under normal atmospheric conditions has a mass of about 1.2
kilograms. When it is moving it has kinetic energy (E=½mv 2). If the rotor
of a wind turbine has a diameter of 100 metres then it sweeps out an area
of over 7500 square metres (i.e. π r 2).
If, for example, the wind speed is 12 metres per second then the volume of
air moving through the rotor area every second is 12 × 7500 = 90,000 m3.
This has a mass of 108,000 kg (i.e. 90,000 × 1.2) and its kinetic energy is
7.8 MJ (E=½mv 2).
For further information visit
www.energy.siemens.com/hq/en/renewable-energy/
wind-power/
If the turbine has extracted energy from it then that mass of air is slowed
down. If it has slowed to 10 m/s then its kinetic energy is reduced to 4.5 MJ.
The turbine has therefore removed 3.3 MJ from the air (7.8 − 4.5 MJ). The
power of the turbine is then (theoretically) 3.3 megawatts (MW). This is 42%
of the original wind power (3.3/7.8 = 0.42). Maximum turbine efficiencies
are generally in the range 40% to 45%.
Betz’s Law states that no wind turbine can remove more than 59.3% of the
available kinetic energy from the air. (2 4 ÷ 3 3 = 0.593 = 59.3%).
Find this and other lessons on www.sta.ie
Wind Turbine Technology
Wind
WindTurbine
Turbine
Technology
Technology
Syllabus
Syllabusreferences
references
Student
StudentActivities
Activities
Exa
Ex
The
Themain
mainsyllabus
syllabusreferences
referencesfor
forthe
thelesson
lessonare:
are:
1.1.AAkilowatt
kilowattisisa aunit
unitofofpower.
power.AAkilowatt-hour
kilowatt-hourisisa aunit
unitofofenergy.
energy.
Show
Showthat
thata akilowatt-hour
kilowatt-hourisisequal
equaltoto3.6
3.6million
millionjoules.
joules.
Leav
Lea
Leaving
LeavingCertificate
CertificatePhysics
Physics(HL)
(HL)
2 2
mgh;EkE=k =½mv
½mv
• • Different
Differentforms
formsofofenergy;
energy;EpE=p=mgh;
• • Conversions
Conversionsfrom
fromone
oneform
formofofenergy
energytotoanother.
another.
• • Demonstrations
Demonstrationsofofdifferent
differentenergy
energyconversions.
conversions.
• • Sources
Sourcesofofenergy:
energy:renewable
renewableand
andnon-renewable.
non-renewable.
• • Appropriate
Appropriatecalculations.
calculations.Principle
Principleofofconservation
conservationofofenergy.
energy.(p.(p.27)
27)
• • Electric
Electriccurrent
currentand
andelectric
electricpotential
potential(p.(p.35)
35)
• • Electromagnetic
Electromagneticinduction.
induction.Alternating
Alternatingcurrent;
current;concepts
conceptsofofmutual
mutual
induction
inductionand
andself-induction
self-induction(pp.
(pp.3737– –38)
38)
• • Structure
Structureand
andprinciple
principleofofoperation
operationofofsimple
simplea.c.
a.c.generator
generator(p.(p.44)
44)
Science
Scienceand
andTechnology
TechnologyininAction
Actionisisalso
alsowidely
widelyused
used
bybyTransition
TransitionYear
Yearclasses.
classes.
Learning
LearningOutcomes
Outcomes
On
Oncompletion
completionofofthis
thislesson,
lesson,students
studentsshould
shouldbebeable
ableto:to:
• • Outline
Outlinethe
theprinciple
principleofofoperation
operationofofa agenerator
generator
• • Draw
Drawa alabelled
labelleddiagram
diagramofofa atypical
typicalwind
windturbine
turbine
• • Discuss
Discussthe
thedifference
differencebetween
betweengeared
gearedand
anddirect
directdrive
drivegenerators
generators
• • Explain
Explainthe
thedifference
differencebetween
betweensynchronous
synchronousand
andasynchronous
asynchronous
generators
generators
• • Explain
Explainthe
thedifference
differencebetween
betweeninstalled
installedcapacity
capacityand
andactual
actual
average
averagecapacity
capacity
• • Make
Makea arough
roughestimate
estimateofofthe
thekinetic
kineticenergy
energyofofthe
thewind
windpassing
passing
through
througha aturbine
turbinerotor
rotorand
andestimate
estimatethe
thepotential
potentialpower
powerofofa awind
wind
turbine
turbine(given
(givensome
someinitial
initialdata).
data).
Read
Re
2.2.Ireland’s
Ireland’selectricity
electricityrequirement
requirementininwinter
winterisis3500
3500toto4500
4500MW.
MW.
Assuming
Assumingthere
thereare
are1.4
1.4million
millionhouseholds
householdsininthe
thecountry
countrycalculate
calculate
the
theaverage
averagedaily
dailyenergy
energyuse
use(in(inkW
kWh)h)per
perhousehold.
household.
3.3.Use
Useavailable
availableinformation
informationsources
sourcestotofind
findout
outhow
howrotor
rotorblades
bladesfor
for
wind
windturbines
turbinesare
aremade.
made.Make
Makea aposter
poster(or
(orcomputer
computerpresentation)
presentation)
totoexplain
explainhow
howthe
theconstruction
constructionand
andthe
thechoice
choiceofofmaterials
materialscan
can
reduce
reduceweight
weightofofrotors
rotorswhile
whilemaintaining
maintainingtheir
theirstrength.
strength.
4.4.Compare
Comparethe
theadvantages
advantagesand
anddisadvantages
disadvantagesofofon-shore
on-shoreand
and
off-shore
off-shoresiting
sitingofofwind
windturbines.
turbines.Summarise
Summariseyour
yourfindings
findingsunder
underthe
the
headings:
headings:on-site
on-siteassembly,
assembly,connection
connectiontotothe
thegrid
gridand
andmaintenance.
maintenance.
5.5.Measuring
Measuringthe
theoutput
outputofofa agenerator
generator
For
Forthis
thisexercise
exercisea asmall
smallsolar
solarcell
cellmay
maybebeused
usedasasa agenerator.
generator.
(Later
(Lateryou
youcan
canuse
usethe
thesame
sameprocedure
proceduretotomeasure
measurethe
theoutput
output
power
powerofofa adynamo.)
dynamo.)
AAvoltmeter
voltmeterconnected
connectedtotothe
theoutput
outputwires
wireswill
willgive
givedifferent
differentreadings
readings
depending
dependingononthe
theillumination
illuminationofofthe
thesolar
solarcell.
cell.However,
However,it itwill
willnot
not
measure
measurethe
theoutput
outputpower;
power;power
power= =voltage
voltage× ×current.
current.
Procedure:
Procedure:
Connect
Connecta aresistor
resistor(e.g.
(e.g.100
100Ω)Ω)across
acrossthe
the
terminals
terminalsofofthe
thesolar
solarcell.
cell.
Connect
Connecta avoltmeter
voltmeteracross
acrossthe
theresistor.
resistor.
Power
Power= =voltage
voltage× ×current
current(P(P= =VVI)I)
Voltage
Voltage= =resistance
resistance× ×current
current(V(V= =RRI);I);therefore
thereforeI =I =VV÷ ÷RR
2 2
÷ ÷RR
Therefore
ThereforePP= =VV× ×VV÷ ÷RR= =VV
2 2
If Ifthe
theresistor
resistorisis100
100ΩΩthen
thenthe
thepower
power(in(inwatts)
watts)is:is:VV
÷ ÷100.
100.
(Advanced:
(Advanced:How
Howdoes
doesthe
thechoice
choiceofofresistance
resistanceaffect
affectthe
themax.
max.power?)
power?)
(a)(a)
(b)
(b)
(c)(c)
(d)(d)
(e)(e)
(f)(f)
True/False
True/FalseQuestions
Questions
a)a) InInIreland
Irelandthe
theelectricity
electricitydemand
demandisisaround
around300
300MW.
MW.
TT FF
General
GeneralLearning
LearningPoints
Points
b)b) Wind
Windenergy
energyaccounts
accountsfor
for50%
50%ofofIreland’s
Ireland’stotal
totalannual
annual
energy
energyneeds.
needs.
TT FF
These
Theseare
areadditional
additionalrelevant
relevantpoints
pointswhich
whichare
areused
usedtotoextend
extend
knowledge
knowledgeand
andfacilitate
facilitatediscussion.
discussion.
d)d) AAkilowatt-hour
kilowatt-hour(kW
(kWh)h)isisa ameasure
measureofofenergy.
energy.
TT FF
e)e) Volta
Voltainvented
inventedthe
thebattery
batteryinin1800.
1800.
TT FF
Leav
Lea
f) f) One
Onekilowatt
kilowatthour
hourisisequal
equaltoto3636MJ.
MJ.
TT FF
Whic
Wh
g)g) Direct
Directdrive
drivegenerators
generatorsgenerally
generallyhave
havefewer
fewerpoles
polesthan
than
geared
gearedgenerators.
generators.
TT FF
• • Concerns
Concernsabout
aboutclimate
climatechange
changeand
andthe
thesustainability
sustainabilityofofenergy
energy
resources
resourceshave
haveaccelerated
acceleratedthe
thedevelopment
developmentofofrenewable
renewable
resources
resourcessuch
suchasaswind
windand
andsolar
solarenergy.
energy.
• • Ireland’s
Ireland’simmediate
immediateelectricity
electricityrequirement
requirementisisapproximately
approximately3000
3000
MW
MW(±(±1400
1400MW).
MW).
• • The
Thetotal
totalinstalled
installedwind
windpower
powercapacity
capacityininIreland
Irelandisisabout
about2600
2600
MW.
MW.Because
Becauseofofthe
thevariability
variabilityofofthe
thewind,
wind,the
theactual
actualaverage
averagewind
wind
power
powercapacity
capacityisisabout
about600
600MW.
MW.
• • The
Thetarget
targetset
setbybyGovernment
Governmentisisfor
for40%
40%ofofthe
thecountry’s
country’selectricity
electricity
totobebederived
derivedfrom
fromrenewable
renewableresources
resourcesbyby2020.
2020.
• • Faraday’s
Faraday’sdiscovery
discoveryofofelectromagnetic
electromagneticinduction
inductioninin1831
1831was
was
crucial
crucialtotothe
thedevelopment
developmentofofelectricity
electricitygeneration
generationonona alarge
largescale
scale
——a adevelopment
developmentthat
thattook
tookabout
aboutfifty
fiftyyears.
years.
c)c) The
Thefirst
firstwind-powered
wind-poweredelectricity
electricitygenerator
generatorwas
wasbuilt
builtinin1831.
1831.T T F F
h)h) The
Thefrequency
frequencyofofthe
theelectricity
electricitysupply
supplyininEurope
Europeisisfifty
fiftyhertz.
hertz.T T F F
i) i) The
Theoutput
outputofofasynchronous
asynchronousgenerators
generatorsisisfirst
firstconverted
convertedtoto
direct
directcurrent
currentand
andthen
thentotoalternating
alternatingcurrent
currenttotomatch
matchthe
the
frequency
frequencyand
andphase
phaseofofthe
thegrid.
grid.
TT FF
j) j) The
Themass
massofofa acubic
cubicmetre
metreofofairairisisapproximately
approximately1212kg.
kg.
TT FF
k)k) The
Thekinetic
kineticenergy
energyofofone
onecubic
cubicmetre
metreofofairairmoving
movingatat1010
metres
metresper
persecond
secondisisapproximately
approximately120
120joules.
joules.
TT FF
Check
Checkyour
youranswers
answerstotothese
thesequestions
questionson
onwww.sta.ie.
www.sta.ie.
(g)(g)
(h)
(h)
A.A.
B.B.
C.C.
D.D.
E.E.
e
ate
r
n)
ehe
nce.
e.
gs
ings
ot
er?)
?)
TF F
Wind Turbine Technology
Examination
ExaminationQuestions
Questions
Did
DidYou
YouKnow?
Know?
Leaving
Leaving
Certificate
Certificate
Physics
Physics
(HL)
(HL)
2012,
2012,
Q.Q.
1111
• • Vertical
Vertical
axis
axis
windmills
windmills
forfor
milling
milling
wheat
wheat
were
were
in in
use
use
in in
Persia
Persia
(modern
(modern
Iran)
Iran)
in in
the
the
ninth
ninth
century
century
and
and
possibly
possibly
earlier.
earlier.
One
One
side
side
was
was
sheltered
sheltered
from
from
the
the
wind
wind
byby
a wall;
a wall;
this
this
determined
determined
the
the
direction
direction
ofof
rotation.
rotation.
Mills
Mills
ofof
this
this
type
type
are
are
still
still
in in
use
use
today.
today.
Read
Read
the
the
following
following
passage
passage
and
and
answer
answer
the
the
accompanying
accompanying
questions.
questions.
“ ...
“ ...
AtAt
the
the
moment
moment
about
about
12%
12%
ofof
Ireland’s
Ireland’s
electricity
electricity
needs
needs
are
are
met
met
byby
wind
wind
energy
energy
and
and
it is
it is
planned
planned
toto
increase
increase
this
this
toto
33%
33%
byby
2020.
2020.
3 3
where
where
ρρ
The
The
power
power
PP
ofof
the
the
wind
wind
can
can
bebe
calculated
calculated
from
from
PP
==
ρAv
ρAv
is is
the
the
density
density
ofof
the
the
air,
air,
AA
is is
the
the
area
area
the
the
wind
wind
acts
acts
onon
and
and
v is
v is
the
the
speed
speed
ofof
the
the
wind.
wind.
InIn
theory
theory
it is
it is
possible
possible
toto
extract
extract
58%
58%
ofof
this
this
energy
energy
in in
a wind
a wind
turbine.
turbine.
Much
Much
ofof
the
the
loss
loss
occurs
occurs
asas
the
the
wind
wind
is is
slowed
slowed
down
down
rather
rather
than
than
stopped
stopped
asas
it passes
it passes
the
the
turbine.
turbine.
The
The
rotating
rotating
blades
blades
ofof
the
the
turbine
turbine
transfer
transfer
their
their
energy
energy
toto
anan
a.c.
a.c.
generator,
generator,
which
which
produces
produces
electricity
electricity
byby
electromagnetic
electromagnetic
induction.
induction.
The
The
resulting
resulting
alternating
alternating
supply
supply
has
has
toto
bebe
changed
changed
toto
match
match
the
the
230
230
V,V,
5050
HzHz
that
that
is is
used
used
forfor
electrical
electrical
supply
supply
in in
Ireland.
Ireland.
Many
Many
people
people
are
are
concerned
concerned
about
about
the
the
noise
noise
associated
associated
with
with
wind
wind
turbines.
turbines.
Better
Better
blade
blade
construction
construction
has
has
ledled
toto
reduced
reduced
noise.
noise.
AtAt
about
about
150
150
mm
from
from
a turbine,
a turbine,
typical
typical
sound
sound
intensity
intensity
levels
levels
are
are
4545
dB.
dB.
This
This
reduces
reduces
toto
4242
dBdB
atat
about
about
200
200
mm
away.
away.
These
These
values
values
compare
compare
favourably
favourably
with
with
values
values
ofof
around
around
6060
dBdB
in in
a busy
a busy
office.”
office.”
Adapted
Adapted
from:
from:
Renewable
Renewable
Energy,
Energy,
Edited
Edited
byby
Godfrey
Godfrey
Boyle,
Boyle,
Oxford
Oxford
University
University
Press
Press
in in
association
association
with
with
The
The
Open
Open
University.
University.
(a)(a) What
What
is is
the
the
effect
effect
onon
the
the
power
power
ofof
the
the
wind
wind
if the
if the
wind
wind
speed
speed
is is
doubled?
doubled?
(b)(b) Why
Why
is is
it not
it not
possible
possible
toto
extract
extract
allall
ofof
the
the
energy
energy
in in
the
the
wind
wind
striking
striking
a wind
a wind
turbine
turbine
blade?
blade?
(c)(c) What
What
is is
electromagnetic
electromagnetic
induction?
induction?
(d)(d) How
How
is is
the
the
output
output
voltage
voltage
ofof
a wind
a wind
turbine
turbine
changed
changed
toto
230
230
VV
a.c.?
a.c.?
(e)(e) Estimate
Estimate
the
the
factor
factor
byby
which
which
the
the
sound
sound
intensity
intensity
changes
changes
when
when
you
you
move
move
from
from
a position
a position
which
which
is is
about
about
200
200
mm
away
away
toto
a position
a position
which
which
is is
about
about
150
150
mm
away
away
from
from
a typical
a typical
wind
wind
turbine.
turbine.
(f)(f) What
What
is is
the
the
tiptip
speed
speed
(the
(the
linear
linear
velocity
velocity
ofof
the
the
outer
outer
end)
end)
ofof
aa
blade
blade
ofof
radius
radius
3030
mm
when
when
it completes
it completes
a revolution
a revolution
every
every
33
seconds?
seconds?
TF F
(g)(g) Small
Small
scale
scale
wind
wind
turbines
turbines
are
are
sometimes
sometimes
used
used
toto
charge
charge
batteries.
batteries.
The
The
a.c.
a.c.
output
output
voltage
voltage
has
has
toto
bebe
converted
converted
toto
a d.c.
a d.c.
voltage.
voltage.
How
How
is is
this
this
achieved?
achieved?
TF F
(h)(h) Name
Name
one
one
other
other
renewable
renewable
source
source
ofof
energy.
energy.
TF F
TF F
Leaving
Leaving
Certificate
Certificate
Physics
Physics
(HL)
(HL)
2001,
2001,
Q.Q.
1 (vi)
1 (vi)
TF F
Which
Which
one
one
ofof
the
the
following
following
statements
statements
is is
not
not
correct?
correct?
TF F
A.A. When
When
there
there
is is
a change
a change
in in
the
the
magnetic
magnetic
flux
flux
threading
threading
any
any
closed
closed
loop,
loop,
anan
e.m.f.
e.m.f.
is is
induced
induced
in in
the
the
loop.
loop.
TF F
TF F
TF F
TF F
B.B. AnAn
electrical
electrical
generator
generator
is is
a device
a device
that
that
converts
converts
mechanical
mechanical
energy
energy
toto
electrical
electrical
energy.
energy.
C.C. A A
transformer
transformer
converts
converts
a low
a low
a.c.
a.c.
voltage
voltage
toto
a high
a high
a.c.
a.c.
voltage
voltage
and
and
vice
vice
versa.
versa.
D.D. If an
If an
electric
electric
motor
motor
is is
prevented
prevented
from
from
rotating
rotating
freely,
freely,
the
the
coil
coil
will
will
become
become
hot
hot
and
and
may
may
“burn
“burn
out”.
out”.
E.E. InIn
a circuit
a circuit
using
using
anan
a.c.
a.c.
power
power
source,
source,
a lamp
a lamp
glows
glows
more
more
brightly
brightly
when
when
anan
iron
iron
core
core
is is
inserted
inserted
in in
a solenoid
a solenoid
that
that
is is
in in
series
series
with
with
the
the
lamp.
lamp.
• • InIn
the
the
twelfth
twelfth
century
century
horizontal
horizontal
axis
axis
windmills
windmills
appeared
appeared
in in
Europe.
Europe.
It is
It is
now
now
thought
thought
likely
likely
that
that
these
these
were
were
independent
independent
inventions
inventions
and
and
not
not
copies
copies
ofof
Chinese
Chinese
oror
Indian
Indian
windmills
windmills
from
from
that
that
time.
time.
• • Wind-power
Wind-power
has
has
been
been
used
used
in in
the
the
Netherlands
Netherlands
since
since
the
the
thirteenth
thirteenth
century
century
toto
drain
drain
the
the
land.
land.
InIn
the
the
eighteenth
eighteenth
and
and
nineteenth
nineteenth
centuries
centuries
similar
similar
technology
technology
was
was
used
used
in in
many
many
parts
parts
ofof
the
the
world
world
toto
pump
pump
water
water
from
from
deep
deep
wells
wells
in in
order
order
toto
irrigate
irrigate
agricultural
agricultural
land,
land,
forfor
example
example
in in
America,
America,
Argentina
Argentina
and
and
Australia.
Australia.
• • From
From
the
the
1930s
1930s
small
small
‘wind
‘wind
chargers’
chargers’
were
were
quite
quite
common
common
in in
rural
rural
areas
areas
in in
many
many
countries,
countries,
including
including
Ireland
Ireland
prior
prior
toto
rural
rural
electrification.
electrification.
They
They
were
were
used
used
toto
charge
charge
batteries
batteries
forfor
radio
radio
receivers
receivers
and
and
minimal
minimal
lighting.
lighting.
Biographical
BiographicalNotes
Notes
Werner
Wernervon
vonSiemens
Siemens(1816
(1816– –1892)
1892)
Werner
Werner
Siemens
Siemens
was
was
born
born
in in
Lenthe,
Lenthe,
near
near
Hannover.
Hannover.
OnOn
leaving
leaving
school
school
hehe
entered
entered
the
the
army
army
academy
academy
ofof
Artillery
Artillery
and
and
Engineering
Engineering
which
which
provided
provided
anan
outlet
outlet
forfor
hishis
inventiveness.
inventiveness.
HeHe
devised
devised
anan
alternative
alternative
toto
the
the
Morse
Morse
telegraph
telegraph
and,
and,
with
with
the
the
help
help
ofof
two
two
ofof
hishis
brothers
brothers
setset
upup
anan
electrical
electrical
engineering
engineering
company
company
that
that
grew
grew
into
into
what
what
is is
known
known
today
today
asas
Siemens
Siemens
AG.
AG.
His
His
independent
independent
inventions
inventions
include
include
the
the
first
first
electrically
electrically
operated
operated
lift,lift,
anan
electrically
electrically
operated
operated
bus
bus
(a(a
trolley-bus),
trolley-bus),
a dynamo
a dynamo
and
and
a loudspeaker.
a loudspeaker.
HeHe
advocated
advocated
social
social
democracy
democracy
(vs.
(vs.
capitalism)
capitalism)
and
and
supported
supported
workers’
workers’
rights,
rights,
including
including
their
their
right
right
toto
form
form
unions.
unions.
InIn
1925
1925
a branch
a branch
ofof
the
the
Siemens
Siemens
company
company
was
was
commissioned
commissioned
byby
the
the
fledgling
fledgling
Irish
Irish
Free
Free
State
State
toto
build
build
a hydroelectric
a hydroelectric
power
power
station
station
atat
Ardnachusha
Ardnachusha
onon
the
the
Shannon.
Shannon.
It was
It was
completed
completed
in in
1929
1929
and
and
supplied
supplied
80%
80%
ofof
the
the
country’s
country’s
electricity.
electricity.
It was
It was
atat
the
the
time
time
the
the
largest
largest
ofof
itsits
kind
kind
in in
the
the
world
world
and
and
a model
a model
that
that
others
others
followed.
followed.
Revise
ReviseThe
TheTerms
Terms
Can
Can
you
you
recall
recall
the
the
meaning
meaning
ofof
the
the
following
following
terms?
terms?
Revising
Revising
terminology
terminology
isis
a powerful
a powerful
aid
aid
toto
recall
recall
and
and
retention.
retention.
Alternating
Alternating
current
current
(AC),
(AC),
alternative
alternative
energy,
energy,
alternator,
alternator,
annulus,
annulus,
, direct
, direct
current
current
(DC),
(DC),
direct
direct
drive,
drive,
dynamo,
dynamo,
armature,
armature,
battery,
battery,
CO
CO
2 2
electrolysis,
electrolysis,
electroplating,
electroplating,
field
field
coils,
coils,
fossil
fossil
fuels,
fuels,
frequency,
frequency,
gearbox,
gearbox,
hertz
hertz
(Hz),
(Hz),
induced
induced
voltage,
voltage,
installed
installed
capacity,
capacity,
magnetic
magnetic
field,
field,
magnetic
magnetic
poles,
poles,
megawatt
megawatt
(MW),
(MW),
neodymium
neodymium
magnet,
magnet,
permanent
permanent
magnet,
magnet,
power,
power,
renewable,
renewable,
rpm,
rpm,
slip
slip
rings,
rings,
sustainable,
sustainable,
synchronised
synchronised
Check
Check
the
the
Glossary
Glossary
ofof
terms
terms
for
for
this
this
lesson
lesson
onon
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