The focus of this project has been the complexities of converting the Danish energy system from using coal as a main power source, to sustainable energy, wind energy in particular. The biggest wind farms in Denmark are located at Horns Rev and Anholt. In this assignment the two farms will be described, analysed and compared. The environmental aspects, of constructing a wind farm will be assessed. By the use of a mathematical and physical model, the wind farms will be analysed. The net present value of Anholt wind farm is calculated to prove that it is financially viable to invest in wind energy. A description of electrolysis is also included. This is used to convert power into gas, when turbines are overproducing electricity. Furthermore, the problems and/or benefits of replacing coal-fired power plants with wind energy will be discussed.

1. Group&3& & Semester&project&2014&
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Offshore(wind(farms(–(Horns(Rev(and(Anholt(
Semester(project(Energy(Technology(Autumn(2014(
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Aagaard,&Søren&Andreas;&071290&
Christensen,&Kristoffer;&030395&
Korsgaard,&Jonas;&270993&
Nissen,&Christian;&190991&
Olesen,&Mads&Odsgaard;&131092&
Plougmann,&Alexander;&110191&
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2. Group&3& & Semester&project&2014&
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!
Title:!! !
Offshore&wind&farms&–&Horns&Rev&and&
Anholt&&
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Project:!
& 1st&semester&project&
!
Project!period:!!
& September&2014&–&December&2014&
&
Project!group:!
& Group&3&
&
Students:!
& Søren&Andreas&Aagaard&
& Kristoffer&Christensen&
& Jonas&Korsgaard&
& Christian&Nissen&
& Mads&Odsgaard&Olesen&
& Alexander&Plougmann&
&
Supervisor:!
& Muhyiddine&Jradi&
!
Number!of!copies:&3&
Pages:&55&
Number!of!characters:&72.000&
Space!occupied!by!figures:&20%&
Appendix!amount!and!>kind:!49&pages&
Course!code:!ETVEEEEVE1&
Finished!on!16>12>2014!
!
The!content!of!the!rapport!is!freely!accessibly,!but!publication!(with!source!is!acknowledged)!is!only!allowed!with!permission!
from!the!authors.
&
Abstract!!
The&focus&of&this&project&has&been&the&
complexities&of&converting&the&Danish&
energy& system& from& using& coal& as& a&
main& power& source,& to& sustainable&
energy,&wind&energy&in&particular.&&
The& biggest& wind& farms& in& Denmark&
are&located&at&Horns&Rev&and&Anholt.&
In&this&assignment&the&two&farms&will&
be& described,& analysed& and&
compared.& The& environmental&
aspects,& of& constructing& a& wind& farm&
will&be&assessed.&
By& the& use& of& a& mathematical& and&
physical& model,& the& wind& farms& will&
be&analysed.&&
The&net&present&value&of&Anholt&wind&
farm& is& calculated& to& prove& that& it& is&
financially& viable& to& invest& in& wind&
energy.&&
A& description& of& electrolysis& is& also&
included.& This& is& used& to& convert&
power& into& gas,& when& turbines& are&
overproducing&electricity.&
Furthermore,& the& problems& and/or&
benefits&of&replacing&coalVfired&power&
plants& with& wind& energy& will& be&
discussed.&
&
&
&
The&Faculty&of&Engineering&
University&of&Southern&Denmark&
Niels&Bohrs&Allé&1&
5230&Odense&M&&
http://sdu.dk&

3. Group&3& & Semester&project&2014&
& Page 3 of 55&
Preface(
&
The&overall&goal&with&this&project&was&to&gain&bigger&understanding&concerning&renewable&energy&–&in&
particular&wind&energy.&Danish&electricity&is&mostly&coming&from&coalVfired&power&plants,&which&is&a&big&
issue&towards&the&environment&in&Denmark&and&in&the&world&nowadays.&Fossil&fuels&are&slowly&
destroying&the&planet&and&therefore&the&research&on&renewable&energy&is&playing&a&big&role&in&today’s&
society.&Denmark’s&biggest&share&in&this,&are&wind&turbines.&In&Denmark&the&goal&is&to&become&
completely&independent&of&fossil&fuels&in&the&future,&but&right&now&the&overall&plan&is&that&35&%&of&all&
Danish&energy&has&to&come&from&renewable&energy&by&the&year&of&2020.&&
&
This&assignment&is&written&to&obtain&knowledge&of&the&construction&of&the&Danish&power&grid,&the&wind&
turbines&and&their&impact&on&the&total&Danish&energy&production.&The&assignment&is&discussing&the&
various&issues&regarding&the&erection&and&disposal&of&wind&turbines,&but&also&giving&insight&in&the&
construction&by&giving&a&mathematical&model&of&wind&turbines.&The&consequences&and&possibilities&of&
replacing&all&coalVfired&power&plants&with&wind&turbines&are&being&discussed&as&well.&&
&
By&working&with&Muhyiddine&Jradi,&Professor,&Assistant,&Centre&of&Energy&Informatics,&this&assignment&
has&been&a&lot&easier&to&work&with&and&he&has&been&a&great&help&in&the&understanding&of&the&issues&
regarding&this&topic.&
&
16th&of&December&2014&
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& & & &
Alexander&Plougmann&
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& & & &
Jonas&Korsgaard&
&
& & &
Mads&O.&Olesen&
&
&
&
&
& & & &
Christian&Nissen&
&
& & &
Kristoffer&Christensen&
&
& & &
Søren&A.&Aagaard&

4. Group&3& & Semester&project&2014&
& Page 4 of 55&
Symbol! Name! Unit!
A! Annuity& DKK&
AC! Alternate&Current& V&
AEC! Alkaline&Electrolysis& &
As! Areal&of&wing&span&& m2&
aq! Aqua& &
Cl! Lift&Coefficient&& &
Cd! Drag&Coefficient& &
Cp! Power&Coefficent& &
DC! Direct&Current& V&
DKK! Danish&Crowns& DKK&
e.g.! Example&Given& &
F! Force& N&
G! Gas& &
GLPS! Global&Lightning&Protection&Service& &
HAWT! Horizontal&Axis&Wind&Turbine& &
HVAC! High&Voltage&Alternate&Current& V&
HVDC! High&Voltage&Direct&Current& V&
HVDC>LCC! High&Voltage&Direct&CurrentVLine&Commutated&Converter& V&
HVDC>VSC! High&Voltage&Direct&CurrentVVoltage&Source&Converter& V&
I! Moment&mass&of&inertia& Kg*m2&
i! Rate&of&return& %&
i.e.! Id&Est&(That&Is)& &
J! Joule& J&
km! Kilometres& km&
kWh! Kilo&Watt&Hours& kWh&
L! Length& m&
l! Liquid& &
LCA! Life&Cycle&Analysis& &
M! Mass& kg&
!! Mass&Flow& Kg/s&
m3! Cubic&Metres& m3&
MARR! Minimum&Attractive&Rate&of&Return& %&
N! Years& Years&
NPV! Net&Present&Value& DKK&
P! Power& J&
PEMEC! Polymer&Electrolyte&Membrane&Electrolysis&& &
PV! Present&Value& DKK&
R! Radius& m&
r! Inflation&rate& %&
RPM! Rotations&per&minute& &
R&D! Research&and&development& &
sec! Seconds& s&
SOEC! Solid&Oxide&Electrolysis& &

5. Group&3& & Semester&project&2014&
& Page 5 of 55&
V! Volts& V&
v! Velocity& m/s&
VAWT! Vertical&Axis&Wind&Turbine& &
W! Watt& J/s&
T! Temperature& K&
℃! Degrees&Celcius&(Temperature)& ℃&
€! Euro& €&
∆!°! The&Gibbs&Free&Energy& kJ/K&
∆!!°! Enthalpy&of&reaction& kj/mol&
∆!°! Entropy& kJ/mol*K&
!!! Electromotive&Force& V&
!! Density& Kg/m3&
!! Angular&Velocity& Rad/s&
!& Magnetic&Flux& Wb&
!& Impedance& Ohm&(Ω)&
&
&
! &

6. Group&3& & Semester&project&2014&
& Page 6 of 55&
Table(of(contents(
1!PHYSICAL!AND!MATHEMATICAL!MODEL!OF!A!WIND!TURBINE! 9&
1.1!WIND!ENERGY!SYSTEMS! 9&
1.1.1&FOUNDATION:& 10&
1.1.2&NACELLE:& 11&
1.1.3&ROTOR:& 11&
1.2!TRANSMISSION! 12&
1.2.1&DENMARK’S&TRANSMISSIONVGRID& 12&
1.2.2&CABLES& 13&
1.2.3&SYNCHRONOUS&ZONES& 13&
1.3!ECONOMY! 14&
1.3.1&PRICES&FOR&CONVERTER&STATIONS.& 14&
1.4!DESCRIPTION!AND!EXPLANATION!OF!THE!MODEL! 15&
1.4.1&COLLECTION&OF&DATA& 15&
1.4.2&CALCULATIONS& 15&
2!COMPARATIVE!ANALYSIS!OF!ANHOLT!AND!HORNS!REV! 18&
2.1!HORNS!REV!OVERVIEW! 18&
2.2!ANHOLT! 18&
2.3!COMPLEXITIES!FOR!AN!OFFSHORE!WIND!FARM! 19&
2.4!DEVELOPMENT!IN!AN!OPTIMIZATION!POINT!OF!VIEW! 20&
2.5!SUGGESTIONS!FOR!IMPROVING!THE!FUTURE!OFFSHORE!WIND!FARMS! 20&
3!NET!PRESENT!VALUE! 21&
3.1!THE!NET!PRESENT!VALUE!OF!ANHOLT!OFFSHORE!WIND!FARM! 21&
3.2!ASSUMPTIONS! 21&
3.2.1&POWER&PRICE& 22&
3.2.2&SALVAGE&VALUE& 22&
3.2.3&THE&EXPENSES& 22&
3.2.4&INFLATION& 22&
3.3!CALCULATION!OF!THE!NPV! 23&
4!ANALYSIS!OF!ENVIRONMENTAL!ASPECTS! 26&
4.1!CONSTRUCTION!PERIOD! 26&
4.2!LONG!TERM!EFFECTS! 26&
4.3!EFFECT!ON!BIRDS! 27&
4.4!VISUAL!IMPACT! 28&
4.5!IMPACT!ON!THE!OVERALL!DANISH!CO2!EMISSIONS! 28&
4.6!DISPOSAL! 30&
5!THE!CURRENT!DANISH!POWER!GRID!TOWARDS!2020! 31&
5.1!THE!FUNCTIONALITY!OF!THE!POWER!GRID! 31&
5.2!SECURITY!OF!SUPPLY!IN!THE!POWER!GRID! 32&
6!FLUCTUATION!OF!ENERGY!PRICES!AND!SOLUTIONS! 33&

7. Group&3& & Semester&project&2014&
& Page 7 of 55&
6.1!FLUCTUATION!OF!ENERGY!PRICES! 33&
6.1.1&OUTSIDE&INFLUENCES& 33&
6.1.2&RENEWABLE&SOURCES&IMPACT&ON&THE&FLUCTUATIONS& 33&
7!ELECTROLYSIS! 37&
7.1!WHY!FOCUS!ON!ELECTROLYSIS?! 37&
7.2!ELECTROLYSIS!TECHNOLOGIES! 37&
7.2.1&ALKALINE&ELECTROLYSIS&(AEC)& 37&
7.2.2&TECHNOLOGY&OVERVIEW& 38&
7.2.3&RESEARCH&AND&DEVELOPMENT&(R&D)& 38&
7.3!OUTLINE!THE!TECHNOLOGY!FOR!AN!ELECTROLYSIS!PLANT! 39&
7.4!ELECTROLYSIS!THROUGH!POWER!PROVIDED!BY!WIND!TURBINES! 39&
7.4.1&THERMODYNAMICS& 39&
7.4.2&HYDROGEN&PRODUCTION& 40&
7.5!PUT!INTO!PERSPECTIVE!THE!POSSIBILITIES!OF!USING!HYDROGEN!IN!THE!ENERGY!SECTOR! 41&
7.5.1&ENERGY&VALUE&CHAIN& 41&
7.5.2&PRODUCTION& 41&
7.5.3&CONVERSION&–&PHASE&1& 41&
7.5.4&STORAGE& 42&
7.5.5&CONVERSION&–&PHASE&2& 42&
7.5.6&END&USERS& 42&
7.6!BALANCING!THE!ENERGY!SYSTEM!BY!THE!USE!OF!HYDROGEN!AND!FUEL!CELLS! 42&
7.6.1&SMART&GRID&V&ELECTROLYSIS& 42&
7.6.2&STORAGE&OF&ELECTRICITY& 42&
DISCUSSION! 44&
CONCLUSION! 45&
REFERENCES! 46&
APPENDIX! 55&
&
! (

8. Group&3& & Semester&project&2014&
& Page 8 of 55&
Introduction(
&
Since&the&start&of&the&industrial&revolution&there&has&been&a&tremendous&lift&in&the&quality&of&life&for&
people.&This&has&however&had&a&great&impact&on&the&overall&climate&conditions.&The&use&of&coal&and&oil&
for&production&of&energy&and&transport&has&changed&the&climate&balance.&To&prevent&this&from&
escalating&any&further,&an&international&agreement&was&established&at&Kyoto.&This&was&a&steppingstone&
for&an&increased&focus&upon&the&issues&caused&by&the&greenhouse&effect.&&
Denmark&has&committed&to&reduce&its&overall&impact&on&climate&change.&To&ensure&a&focused&effort&on&
this,&Denmark&signed&an&agreement&in&March&2012,&dedicating&itself&to&increase&the&amount&of&
electricity&produced&by&wind&turbines&to&50%.&&This&is&a&part&of&the&overall&plan&for&reducing&the&total&
CO2&emission,&by&40%&in&2020&compared&to&1990.&&
To&ensure&this,&a&lot&of&issues&need&to&be&dealt&with,&and&a&broader&understanding&is&needed.&The&
following&project&will&give&an&overall&understanding&of&the&issues&faced&today&and&in&the&future.&&
We&are&considering&two&wind&farms,&Horns&Reef&and&Anholt&Wind&Farm,&for&analysis.&
There&will&be&made&a&thorough&mathematical&and&physical&model&of&an&offshore&wind&farm,&where&
analysing&environmental&aspects,&including&the&impact&it&has&on&the&total&Danish&CO2&emission,&will&be&
included.&Furthermore&the&analysis&will&compare&the&two&wind&farms&by&different&measures.&Discussing&
how&the&visions&of&replacing&all&Danish&coalVfired&power&plants&with&energy&from&wind&turbines&have&
on&the&environment&and&the&Danish&power&grid’s&stability.&The&focus&will&be&regarding&why&this&may&
have&a&negative&effect&on&the&stability&and&how&we&can&prevent&this&by&using&present&and&future&
technology.&Calculating&the&net&present&value&of&Anholt&wind&farm,&the&wind&farm&will&be&projected&
through&a&cost&benefit&analysis&to&estimate&future&profits.&
To&limit&the&extent&of&the&assignment&the&focus&will&be&on&wind&turbines&in&a&Danish&context.&&&&
&
To&make&the&assignment&easy&to&reed,&every&section&is&started&by&an&introduction,&followed&by&the&main&
text&with&footnotes&for&easy&access&to&literature&and&a&numerated&structure&of&each&paragraph&and&
figure.&The&results&found&are&summed&up&in&a&partial&conclusion&written&in&italic,&that&leads&up&to&a&
discussion&and&a&final&conclusion.&&
& &

9. Group&3& & Semester&project&2014&
& Page 9 of 55&
1(Physical(and(mathematical(model(of(a(wind(turbine((
1.1(Wind(energy(systems(
The&purpose&of&wind&energy&systems&is&to&convert&the&kinetic&energy&from&air&into&electric&energy,&
which&then&can&be&utilized&by&electric&applications.(
When&discussing&wind&energy&systems,&two&main&technologies&are&on&the&table.&The&Horizontal&Axis&
Wind&Turbine&(HAWT)&and&the&Vertical&Axis&Wind&Turbine&(VAWT).&&
The&HAWT&technology&is&the&most&used&technology&for&largeVscale&purposes,&including&the&technology&
used&both&at&Anholt&and&Horns&Rev&Wind&farm.&Therefore,&the&focus&in&the&following&will&be&on&the&
HAWT.&
&
In&general,&the&structure&of&HAWTs&is&rather&complex,&due&to&their&usually&large&size.&The&structure&of&a&
standard&HAWT&could&be&as&follows:&
&
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Fig.!1.1:!Model&of&a&wind&turbine1!
&
The&most&noteworthy&main&components&of&the&wind&turbine&are&the&foundation,&the&Nacelle&and&the&
rotor.&
&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
1&“Energy&Systems”:&Lecture&5,&PowerPoint&slide&24&

10. Group&3& & Semester&project&2014&
& Page 10 of 55&
1.1.1(Foundation:(
The&foundation&of&the&wind&turbine&is&an&important&component&of&the&structure&in&terms&of&economy&
and&stability.&When&choosing&and&designing&foundations&for&offshore&wind&turbines,&considering&the&
size&of&the&turbine,&soil&conditions&and&depth&of&water,&is&very&important.&There&are&3&basic&foundationV
types:2&
• Gravity&foundation&
• Monopile&foundation&
• Jacket&foundation&
Fig.!1.2:&Model&of&foundations2&
!
In&shallow&waters,&depth&5V20&meters,&the&most&commonly&used&turbine&foundation&is&monopile&(about&
70%&of&all&wind&turbine&foundations)&and&gravity.&In&deeper&waters,&the&wind&turbines&are&bigger,&
which&means&bigger&foundations&in&diameter.&This&attracts&bigger&waves&and&creates&issues&with&
stability&and&installation.&&
In&the&depth&of&20V35&meters,&it&is&possible&to&use&monopile,&gravity&or&jacket&foundation.&One&of&the&
advantages&of&using&jacket&foundation&is&less&wave&load&and&therefore&this&type&of&foundation&has&the&
best&potential&at&deeper&waters,&compared&to&monopile&and&gravity.&This&type&of&foundation&is&more&
expensive,&but&calculations&by&Rambøll&have&shown&that&the&costs&of&using&jacketV&or&monopileV
foundation&are&equal&at&a&depth&of&35&meters.&Depths&below&35&meters&therefore&suggest&the&use&of&
jacket&foundation.&
Due&to&the&large&costs&of&foundations&in&deep&water,&research&is&carried&out&involving&e.g.&floating&
foundations.&
&
Both&AnholtV&and&Horns&Rev&wind&farm&is&constructed&with&monopile&foundations&due&to&the&placement&
in&shallow&waters.&
&
& !
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2&Appendix&D&–&The&HAWT&
Depth:!5?20m!Depth:!20?35m!Depth:!35m!and!
below!

11. Group&3& & Semester&project&2014&
& Page 11 of 55&
1.1.2(Nacelle:(
The&nacelle&is&the&“house”&of&all&the&mechanical&and&electrical&controls&e.g.&gearbox,&generator&and&
control&system.&
Two&types&of&drive&systems&are&usually&available&for&wind&turbines:3&
• Drive&system&with&gearbox&
• Direct&drive&system&without&gearbox&
&
1.1.3(Rotor:(
The&rotor&consists&of&the&Hub,&the&blades&and&sometimes&blade&pitchVdrives&are&interposed.&
Mounted&into&the&hub&are&the&blades.&The&manufacturers&often&consider&these&the&most&crucial&part&of&a&
turbine&due&to&their&great&impact&on&the&electrical&output.&&
Through&the&blade&design&the&rotation&of&the&rotor&is&created&because&of&aerodynamics.&Today&blades&
are&molded&with&an&airfoil,&known&from&the&aviation&industry,&to&create&uplift&and&therefore&rotating&
the&blades.&The&design&of&the&blades&tends&to&become&complex.&&
&
The&pitch&drives&can&be&interposed&between&the&blades&and&the&HUB.&The&main&goals&of&these&drives&
are:&
• To&ensure&the&rotor&speed&is&within&its&operation&limits&by&regulating&the&angle&of&attack&with&
respect&to&the&change&in&wind&speed.&In&other&words,&maximizing&the&output&of&the&wind&
turbine.&
• A&safety&precaution&in&case&of&wind&speeds&above&the&maximum&rated&wind&speed&and&in&case&of&
emergency&shutdowns.&In&both&cases&by&feathering&(minimizing&frontal&surface&area&in&the&
wind&direction)&the&blades&to&stop&rotation.&
In&other&words,&the&pitch&drives&are&regulating&the&rotational&speed&of&the&wind&turbines.&
&
It&is&important&to&regulate&the&wind&turbines&daily,&to&ensure&maximum&output&and&secure&them&when&
weather&conditions&are&bad.&
&
Engineers&and&designers,&use&aerodynamic&principles&like&feathering&and&stall,&as&tools&for&regulating&
the&turbine.&
&
Types&of&regulation4:&
• Pitch&control&
• Stall&control&
• Active&stall&control&
&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
3&Appendix&D&–&The&HAWT&
4&Appendix&D&–&Types&of&regulation&

12. Group&3& & Semester&project&2014&
& Page 12 of 55&
1.2(Transmission(
This&section&will&be&regarding&the&Danish&transmission&grids&construction.&The&key&components&to&the&
grid&will&be&explained&together&with&each&of&the&components&significance&to&the&transmission&by&either&
electricity&by&high&voltage&alternating&current&(HVAC)&and&high&voltage&direct&current&(HVDC).&The&
technical&advantages&and&disadvantages&will&be&illuminated&in&the&following.&
1.2.1(Denmark’s(transmissionOgrid((
Transmission&is&within&electricity&an&expression&of&a&transfer&of&energy.&By&transmission&is&understood&
a&transfer&of&electricity&from&one&place&to&another.&The&Danish&transmission&grid&consists&of&overhead&
AC&high&voltage&wire.&The&voltages&in&high&voltage&wires&in&Denmark&are&up&to&400&kV,&which&entails&a&
significantly&lower&energy&loss5.&The&Danish&grid&is&divided&into&three&different&transmission&levels.&The&
highest&level&are&on&400&kV&and&is&the&superior&electricity&transmission&grid,&that&both&domestic&and&
abroad&is&used&to&connect&the&larger&power&plants&to&one&another&and&to&destitute&the&energy&to&lower&
transmission&grids.&The&middle&level&is&the&regional&transmission&grid,&it&is&either&on&150&kV&or&132&kV.&
This&connects&the&superior&transmission&grid&to&the&distribution&grid,&which&is&the&third&and&final&
voltage&level&in&Denmark.&
&
Fig.!1.3:&The!three!voltage!levels!in!the!Danish!power!grid6.!
&
Overhead&high&voltage&lines&have&been&around&for&several&decades,&because&of&its&ability&to&transmit&
high&voltage&almost&without&any&danger&to&the&surroundings.&This&method&to&transmit&current&has&been&
tested&thorough,&to&map&the&strengths&and&weaknesses.&Even&though&the&weaknesses&is&not&nearly&as&
substantial&in&a&country&like&Denmark&like&it&is&in&countries&like&Russia&and&USA,&where&extreme&
weather&conditions&are&more&frequent.&A&weakness&in&Denmark&would&be&the&significant&amount&of&
water,&more&especially&all&the&islands&and&offshore&wind&farms,&in&these&cases&submerged&cables&is&the&
only&solution.&The&conditions&under&water&are&different,&and&that&needs&to&be&taken&into&account&
weather&or&not&it&would&be&favourable&to&use&HVDC&instead&of&HVAC.&There&are&advantages&and&
disadvantages&in&both&types,&which&will&be&discussed&in&the&following&chapters.&&
& !
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
5&Appendix&D&V&Transformer&
6http://www.energinet.dk/SiteCollectionImages/DK/ANL%C3%86G%20OG%20PROJEKTER/Br%C3%B8dtekst
%20grafik%20max%20454%20bred/KJE%20reaktiv%20kompensering.jpg&

13. Group&3& & Semester&project&2014&
& Page 13 of 55&
1.2.2(Cables(
Burial&of&cables&over&the&countryside&has&been&used&for&several&years&in&Denmark.&It&is&more&expensive&
to&transmit&power&through&buried&cables,&but&it&insures&stability,&because&wind&and&weather&cannot&
inflict&damage&to&the&cable.&Furthermore,&cables&do&not&disturb&nature&in&the&same&way&as&overhead&
wires,&which&is&an&important&factor&when&deciding&whether&to&use&buried&cables&or&overhead&wires.&If&
transmission&is&needed&under&water,&it&is&a&necessity&to&use&cables.&
&One&of&the&problems&with&using&buried&cables&instead&of&overhead&wires&is&that&a&cable&sheath&protects&
the&core&in&the&cable,&in&this&cable&sheath&is&a&voltage&on&0&V.&In&regular&overhead&wires&occurs&a&
capacitance&between&the&wires,&while&in&cables&the&capacitance&occurs&between&the&wire&and&the&cable&
sheath.&The&size&of&the&capacitance&is&depended&on&the&distance&between&the&two&conductors.&Because&
of&the&distance&is&far&greater&in&the&overhead&wires&than&in&a&cable,&the&capacitance&is&greater&in&cables&
than&in&the&wires.&A&second&problem&is&heat&in&transmission.&Heat&is&produced&as&a&byVproduct&in&the&
conductors,&but&because&it&is&possible&for&overhead,&wire&to&dispose&of&the&heat&more&efficiently&than&
buried&cables,&and&because&of&that&the&cables&will&be&heated&the&most.&Because&the&resistance&in&the&
conductor,&will&increase&the&more&the&conductor&is&heated.7&
!
1.2.3(Synchronous(zones(
The&world’s&power&grid&is&based&on&ACVconnections.&These&ACVconnections&are&divided&into&different&
zones&all&over&the&world,&inside&the&zones&the&current&are&synchronous.&The&zones&are&a&synchronous&in&
relation&to&one&another,&which&means,&the&frequency&is&not&precisely&the&same.&That&makes&it&
impossible&to&transmit&AC&from&one&zone&to&another.&This&is&a&reality&in&Denmark&too,&Zealand&belongs&
to&the&Nordic&zone&and&Jutland,&Funen&and&Germany&belongs&to&the&European&zone.&To&solve&this&
problem&DC&connections&are&often&used.&When&converting&the&AC&to&DC&the&current&evens&out,&and&
afterwards&converted&back&to&AC&now&adjusted&to&the&zone&the&power&is&being&transmitted&too.&This&
method&is&being&used&in&the&connection&between&Funen&and&Zealand.& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
7&Raymond!A.!Serway!og!John!W.!Jewett.!Physics!for!Scientists!and!Engineers!with!Modern!Physics,!Eighth!Edition&

14. Group&3& & Semester&project&2014&
& Page 14 of 55&
1.3(Economy(
Converter&stations&of&different&type&and&capacity&prices&and&energy&losses&are&compered.&
1.3.1(Prices(for(converter(stations.(
The&price&difference&on&the&cables&used&for&AC&and&DC&are&close&to&insignificant,&why&in&this&rapport&it&
has&been&chosen&to&ignore&it.&Focus&has&been&on&the&converter&stations&and&the&loss&of&power.&
&
The&total&price&for&converter&stations&on&different&capacity&levels:&
&
&
&
&
&
Table!3.1:&Price!for!converter?!and!transformer!stations.8!!
HVDC?LCC:!high!voltage!direct!current?line!commutated!converter.!!
HVDC?VSC:!high!voltage!direct!current?voltage!source!converter.!!!&
&
&Table&for&converter&stations:&&
&
&
&
&
Table!3.2:&Converting!loss!in!pct.5!&
&
VSC&has&larger&a&higher&cost&at&construction&and&a&larger&energy&loss&due&to&the&conversion&than&LCC.&&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
8&Cigré!B4.52.!HVDC!Grid!Feasibility!study,!2013.!
&
Converter&station&& HVAC&& HVDCVLCC&& HVDCVVSC&&
500MW&& 16&mio.&€&& 40&mio.&€&& 51&mio.&€&&
1000MW&& 28&mio.&€&& 90&mio.&€&& 110&mio.&€&&
1500MW&& 40&mio.&€&& 120&mio.&€&& 153&mio.&€&&
Converter&station&& HVDCVLCC&& HVDCVVSC&&
500MW&& 0,85&pct.&& 1&pct.&V&2&pct.&&
1000MW&& 0,75&pct.&& 0,9&pct.&V&1,75&pct.&&

15. Group&3& & Semester&project&2014&
& Page 15 of 55&
1.4(Description(and(explanation(of(the(model(
1.4.1(Collection(of(data(
This&sections&data&is&based&on&Anholt&wind&farm.&Siemens&manufactured&the&model&SWT&3.6&120,&which&
is&the&model,&used&in&Anholt.&
The&wind&farm&consists&of&111&turbines,&each&with&a&capacity&of&3,6MW,&which&makes&the&total&capacity&
of&the&wind&farm&400MW.&From&data&received&from&Siemens&it&was&possible&to&create&a&model&of&the&
wind&turbine.&
&
1.4.2(Calculations(
Based&on&the&turbines&specific&power&curve,&there&were&made&a&bestVfit&trend&line&(look&in&appendix)&
descripted&by&this&3.&degree&polynomial:&
&
Power!output!=!?12,397*w3!+!202,82*w2!–!478,57*w!+!512,97!!!(1.1)!
&
Data&from&Siemens&showed&that&the&turbines&RPM&value,&at&the&lowest&point&is&5&RPM&and&at&the&
highest&point&13&RPM.&An&assumption&was&made&that&the&RPM&value&would&rise&linear,&there&were&
made&an&estimate&on&the&RPM&at&each&wind&speed.&
Due&to&the&previously&estimate&of&the&RPM&enough&data&is&gathered&to&calculate&the&blade&tip&speed.&
&
!"#$%!!"#!!"##$ =
!"#
!!"
!!"
∗ !"#$%&'#!!"#$%&%' ∗ !
60
!!!(1.2)&
&
The&gathered&data&is&plotted&into&a&diagram&and&a&bestVfit&trend&line&(look&in&appendix)&descripted&this&
1.&Degree&polynomial:&
&
!"#$%!!"#!!"##$ = 5,5817! + 25,847&&&(1.3)&
&
The&air&density&has&an&impact&on&how&efficient&the&turbines&are.&It&is&calculated&from&this&formula:&
&
!"#!!"#$%&' =
!"#!"#$%!!"#$$%"#
!"#!!"#$%&#% !"# ∗ !"#$"%&!'%" ! + 273,15
!!!(1.4)&
&
Data&given&by&Siemens&are&used&to&calculate&the&area&of&the&wingspan:&
&
!"#$!!"!!"#$%&'# =
!"#$%&'#!!"#$%&%'
2
!
∗ !!!!(1.5)&
&
The&power&coefficient&is&a&number,&which&indicates&how&much&of&the&winds&potential&energy&there&is&
utilized&into&electric&energy.&The&German&physicist&Albert&Betz,&made&a&discovery,&better&known&as&
“Betz&law”&that&a&wind&turbine&never&will&be&able&to&have&a&power&coefficient&above&16/27.&The&reason&
will&be&explained&in&the&following:&
It&is&assumed&that&the&average&wind&velocity&is:&
! =
!! + !!
2
!!!(1.6)&

16. Group&3& & Semester&project&2014&
& Page 16 of 55&
! = ! ∗ !! ∗ ! = ! ∗ !! ∗
!! + !!
2
!!!(1.6)&
&
Energy&consumed&from&the&wind&by&the&rotor:&
! =
1
2
∗ ! ∗ !!
!
− !!
!
!!!(1.7)&
&
Merging&the&two&equations&
! =
1
2
∗ ! ∗ !! ∗
!! + !!
2
∗ !!
!
− !!
!
!!!(1.8)&
! =
1
4
∗ ! ∗ !! ∗ !! + !! ∗ !!
!
− !!
!
!!!(1.9)&
&
Power&in&the&wind:&
!! =
1
2
∗ ! ∗ !! ∗ !!
!
!!!(1.10)&
&
The&relation&between&P&and&P0:&
!
!!
=
1
4
∗ ! ∗ !! ∗ !! + !! ∗ !!
!
+ !!
!
1
2
∗ ! ∗ !! ∗ !!
!
!!!(1.11)&
!
!!
=
1
2
∗ 1 +
!!
!!
∗ 1 −
!!
!!
!
!!(1.12)&
! =
!!
!!
!!!(1.13)&
!! =
1
2
∗ 1 + ! ∗ 1 − !!
!!!(1.14)&
!!!
!"
=
1
2
∗ 1 + ! ∗ 1 − !!
!!"!!!(1.15)&
!!!
!"
=
1
2
−
!!
2
+
!
2
−
!!
2
!!"!!!(1.16)&
!! = −2! + 1 − 3!!
!!!(1.17)&
0 = −3! − 2! + 1!!!(1.18)&
! =
−! ± !! − 4!"
2!
=
2 ± 2! − 4 ∗ −3 ∗ 1
2 ∗ −3
!!!(1.19)&
! =
1
3
!!!(1.20)&
!! =
1
2
∗ 1 +
1
3
∗ 1 −
1
3
!
!!!(1.21)&
!! =
16
27
≈ 0,59!!!(1.22)&
&
& &

17. Group&3& & Semester&project&2014&
& Page 17 of 55&
The&time&to&connect&to&the&grid&has&been&calculated,&and&can&be&seen&in&appendix.9&This&was&found&to&be&
13,87&seconds&from&idling.&
&
&
To!conclude,!different!aspects,!e.g.!stability,!economy!and!efficiency!are!taken!into!consideration!when!a!
wind!turbine!is!build.!These!considerations!will!help!achieve!the!best!possible!potential!for!the!turbine!in!
its!surroundings.!The!efficiency!of!the!wind!turbine!depends!on!the!design!of!the!rotor!and!components!
the!nacelle.!!
&
&
Now&that&there&has&been&given&a&basic&overview&of&how&a&wind&turbine&works,&it&is&time&to&take&a&look&
at&the&two&parks&that&serves&as&a&baseline&for&the&analysis&of&the&Danish&power&grid.&&
&&&&
&
& !
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
9&Appendix&D&–&Mathematical&model&

18. Group&3& & Semester&project&2014&
& Page 18 of 55&
2(Comparative(analysis(of(Anholt(and(Horns(Rev(
2.1(Horns(Rev(overview(
The&project&at&Horns&Rev&started&in&2002&with&phase&1,&also&known&as&Horns&Rev&1.&In&2008&they&began&
the&next&project,&which&was&the&second&phase,&Horns&Rev&2,&which&was&established&in&2010.&In&2017&
they&expect&to&have&finished&the&third&phase&of&Horns&Rev&project,&Horns&Rev&3.&Dong&Energy&operated&
all&three&phases&and&today&the&companies&Dong&Energy&and&Vattenfall&own&it.&You&can&find&more&details&
about&the&three&phases&of&Horns&Rev&project&in&the&appendix.10&
&
&
2.2(Anholt(
Anholt&wind&farm&is&Denmark’s&largest&with&a&total&of&111&wind&turbines.&It&has&a&capacity&of&3,6&MW&
per&unit&and&400&MW&in&total.&It&is&located&between&Djursland&and&the&island&of&Anholt&in&Kattegat&and&
has&an&area&of&88&km2.&It&has&a&water&depth&ranging&from&15V19&m.&The&turbine&model&is&a&SWTV3.6V120&
from&Siemens.&The&111&turbines&are&partially&owned&by&3&companies:&“Dong&Energy”&(50&%),&
“PensionDanmark”&(30&%)&and&“PKA&Pension”&(20&%).&&
The&total&cost&of&the&project&was&1520&mio.&Euros,&and&was&build&by&the&Danish&company&Dong&Energy.&
They&started&building&in&2010&and&finished&the&project&on&time&in&2012.&The&wind&farm&is&producing&
enough&energy&to&supply&about&400.000&Danish&households.&That&is&the&same&as&4&%&of&the&total&Danish&
power&consumption.&In&relative,&the&Danish&environmental&2020Vplan&says&that&35&%&of&the&total&
energy&has&to&come&from&renewable&energy&in&2020.&
&
Anholt&has&the&chosen&this&layout&to&provide&the&most&optimum&position&of&the&wind&turbines&in&order&
to&exploit&the&wind&and&at&same&time&taking&into&account&the&challenging&soil&conditions.&&
&
Fig.!2.1:!Anholt!wind!farm.11!
&
One&of&the&problems&during&the&building&of&Anholt&wind&farm&was&the&restricted&sailing&through&the&
area.&This&caused&a&lot&of&angry&sailors,&who&uses&the&seas&between&Anholt&and&Djursland&very&often.&It&
has&been&discussed&whether&or&not&Dong&Energy&has&been,&and&still&are&being,&paid&too&much&for&the&
electricity&due&to&the&fact&that&the&cost&of&the&111&wind&turbines&was&not&as&much&as&expected.&&
&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
10&Appendix&E&–&Comparative&analysis&of&Anholt&and&Horns&Rev&
11&http://www.anholtVwindfarm.com/en/theVproject/projectVsiteVandVscope&

19. Group&3& & Semester&project&2014&
& Page 19 of 55&
&
&
! Horns!Rev!1! Horns!Rev!2! Anholt!
Turbine!model! Vestas&V80V2.0&MW& Siemens&SWTV2.3V93& Siemens&SWTV3.6V120&
Rated!power!pr.!turbine! 2&MW& 2,3&MW& 3,6&MW&
Wind!farm!capacity! 160&MW& 209,3&MW& 399,6&MW&
Location! Blåvandshuk,&North&Sea& Blåvandshuk,&North&Sea& Grenå,&Kattegat&
Number!of!turbines! 80& 91& 111&
Rated!wind!speed! 16&m/s& 13,5&m/s& 12,5m/s&
Wind!farm!area! 20km2& 33km2& 88km2&
Hub!height! 70m& 68m& 81,6m&
Commission!year! 2002& 2010& 2013&
Estimated!project!cost! 270&mio.&€& 470&mio.&€& 1520&mio.&€&
Structure!type! Monopiles& Monopiles& Monopiles&
Table!2.1:!In!this!table!there!is!the!most!important!information!about!the!3!projects/wind!farms!to!compare!Anholt!
wind!farm!with!Horns!Rev.12!
!
2.3(Complexities(for(an(offshore(wind(farm(
Before&establishing&an&offshore&wind&farm,&different&factors&have&to&be&taken&into&account.&Some&of&
these&are&listed&below.13&
&
• Foundation&cost&
• Cable&cost&
• Wind&
• Connecting&the&wind&farm&to&the&grid&
• Lightning&
&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
12&www.lorc.dk!specified!in!literature!&
13&Appendix&E&V&Complexities&

20. Group&3& & Semester&project&2014&
& Page 20 of 55&
2.4(Development(in(an(optimization(point(of(view(
&
Fig.!2.2:!Size!evolution!of!wind!turbines!over!time.14!
!
The&model&shows&how&the&development&in&optimizing&the&wind&turbines&has&been&over&the&past&29&
years.&Today&there&has&successfully&been&tested&8&and&10&MW&wind&turbines.15&Another&improvement&is&
the&fundament&for&the&turbines.&Today&floating&foundations&are&being&researched.&This&helps&reducing&
the&cost&of&the&offshore&wind&turbines,&and&so&the&cost&of&kWh&will&be&lower.&
&
2.5(Suggestions(for(improving(the(future(offshore(wind(farms(
To&improve&an&offshore&wind&farm&you&have&to&look&at&the&complexities&first.&Some&ways&to&improve&
the&wind&turbines&is&to&make&them&more&effective&and&reduce&the&cost&of&production.&This&can&be&done&
through&the&following&examples:&
• Increased&capacity&
• Fuses&to&protect&from&lightning&
• Better&transportation&of&energy&
• Floating&wind&farms&
• More&space,&which&means&bigger&bladed&and&increased&efficiency&
&
&
The!two!offshore!wind!farms!show!how!the!development!for!wind!technologies!has!been!improved.!
Looking!at!table!2.1,!it!shows!how!the!capacity!of!the!wind!turbine!has!been!improved.!At!the!same!time!
the!size!of!the!farm!and!the!number!of!turbines!has!grown.!Even!though!Horns!Rev!exists!of!two!wind!
farms,!Anholt!wind!farm!is!still!bigger.!Future!wind!farms!are!going!to!be!even!bigger,!if!the!development!
continues.!This!leads!to!improvement!of!cables!and!foundations.!
&
Now&with&a&deeper&understanding&of&both&the&complexity&of&the&turbine&itself,&and&how&the&parks&are&
build,&the&interesting&thing&is&the&economics&behind.&For&the&transition&to&a&future&with&less&fossil&fuel&to&
be&successful,&the&green&alternative&needs&to&be&able&to&compete&on&the&commercial&market.&&
& (
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
14&http://ec.europa.eu/research/energy/eu/index_en.cfm?pg=researchVwind&
15&http://www.powerVtechnology.com/features/featuretheVworldsVbiggestVwindVturbinesV4154395/&

21. Group&3& & Semester&project&2014&
& Page 21 of 55&
3(Net(present(value(
3.1(The(net(present(value(of(Anholt(offshore(wind(farm(
To&calculate&the&net&present&value&there&are&some&values&and&terms&that&needs&to&be&known.&The&NPV&
includes&these&terms:&
• Term&of&project&
o The&time,&which&the&cash&flow,&is&divided&into.&
• Initial&cost&
o The&money&invested&in&the&project&
• Annuity&
o The&cash&flow&into&and&out&of&the&project&
• Salvage&value&
o The&value&that,&you&get&for&the&project&after&its&lifetime.&
&
In&discounting&cash&flow&analysis&there&are&two&additional&terms&that&are&used:&
• Interest&rate&
o The&rate&you&find&if&NPV(i)=0&
• Minimum&attractive&rate&of&return&(MARR)&
o The&minimum&rate&of&return&on&a&project&a&company&is&willing&to&accept&before&starting&
a&project.&
To&find&out&whether&or&not&the&NPV&is&positive,&there&has&to&be&done&a&discounting&analysis&using&the&
MARR&as&discount&rate.&If&the&NPV&of&the&project&is&positive&it&will&be&financially&viable.&The&general&
equation&for&NPV&is:&&
!" = !
1 + ! ! − 1
! 1 + ! !
16!!!(3.1)&
!"# = !"
!
!
!!!(3.2)&
&
The&table&shows&some&of&the&information&about&Anholt&wind&farm&we&need&to&find&the&NPV.&(rest&of&the&
information&is&in&the&calculation&part)&
Investment& 10&billion&kr.&
Commission&year&& 2013&
Wind&farm&lifetime& 25&years&
Table!3.1:!The!investment,!commission!year!and!lifetime!of!Anholt!wind!farm.17!
3.2(Assumptions(
To&find&the&NPV,&it&is&necessary&to&make&some&assumptions.&The&assumptions&needed&are&listed&here:&
• The&power&price&
• Salvage&value&&
• Expenses&
• Inflation&
&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
16&Francis&M.&Vanek,&Louis&D.&Albright&and&Largus&T.&Angenent:&“Energy&Systems&EngineeringV&Evaluation&and&
Implementation”,&Mc&Graw&Hill&Education,&2.&Edition,&page&81&
17&Link&for&information:&http://ipaper.ipapercms.dk/DONGENERGY/Internet/DK/V
WindPower/AnholtOffshoreWindFarm%20DK/&page&3&and&5&

22. Group&3& & Semester&project&2014&
& Page 22 of 55&
3.2.1(Power(price((
The&power&price&for&Anholt&wind&farm&is&1,051&kr/kWh&the&first&20TWh&that&correspond&to&about&12&
years.&After&12&years,&in&year&2026&it&is&assumed&to&decrease&to&the&spot&price&of&power.&The&spot&price&
for&2026&to&2030&can&be&found&in&first&table&in&the&calculation&of&NPV.&Because&the&lifetime&of&the&wind&
farm&will&last&to&year&2038,&the&average&increasing&value&from&2026&to&2030&will&be&assumed&to&be&the&
increase&for&each&year&after&2030.&The&average&increasing&value&is&calculated&by:&
&
( ) ( ) ( ) ( )( ) kWhDKK
kWhDKK
/037,0
4
/583,0594,0570,0583,0488,0570,0447,0488,0
=
−+−+−+−
&&&(3.3)
&
This&value&is&used&to&calculate&the&power&price&after&year&2030.&
&
3.2.2(Salvage(value(
In&the&“Ernst&and&young”&analysis,18&the&salvage&value&or&the&scrap&value&is&found&to&be&52,7&Mio.&DKK.&
This&is&the&cost&to&remove&the&Anholt&wind&farm&after&its&lifetime.&
&
3.2.3(The(expenses(
The&expenses,&is&found&in&table&3.2,&and&is&used&to&calculate&the&annuity.&
&
Table!3.2:!Used!operation!cost!in!the!Anholt!wind!farm!project!(DKK’000).19!
!
The&sum&of&the&expenses&is:&
year1− 5: 182624⋅103
+31608⋅103
+35120⋅103
+3210⋅103
( )DKK = 252,562⋅106
DKK 3.4( )
year 6 − 25: 217744⋅103
+31608⋅103
+35120⋅103
+ 4335⋅103
( )DKK = 288,807⋅106
DKK 3.5( )
&
&
3.2.4(Inflation(
The&inflation&in&Denmark&is&assumed&to&be&0,5%&because&that&is&the&actual&yearly&inflation&in&
Denmark20.&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
18&http://www.ens.dk/sites/ens.dk/files/undergrundVforsyning/vedvarendeVenergi/vindkraftV
vindmoeller/havvindmoeller/idriftsatteVparkerVnye/ErnstYoung%20baggrund_v_1%200.pdf&
19&http://www.ens.dk/sites/ens.dk/files/undergrundVforsyning/vedvarendeVenergi/vindkraftV
vindmoeller/havvindmoeller/idriftsatteVparkerVnye/ErnstYoung%20baggrund_v_1%200.pdf&page&4&
20&http://da.tradingeconomics.com/denmark/inflationVcpi&

23. Group&3& & Semester&project&2014&
& Page 23 of 55&
3.3(Calculation(of(the(NPV!
&
Table!3.3:!Table!of!the!spot!price!in!the!years!2011?2030.21!“Nord!Pool!uvægtet”!are!the!numbers!used.!
&
The&values&for&the&spot&price&are&found&in&table&3.3&and&used&to&calculate&the&NPV&in&table&F.122.&
&
The&power&produced&in&a&year&is&calculated&on&the&assumption&that&20TWh&is&produced&in&12&years.&
1TWh =109
kWh
power produced each year :
20⋅109
kWh
12 months
=1666,67⋅106
kWh / year 3.6( )
&
&
The&annuity&is&calculated&by&using&the&income,&which&is:&
Income1−12 =1,051DKK / kWh⋅1666,67⋅106
kWh / year =1752,02⋅106
DKK / year 3.7( )&
This&is&the&income&for&the&first&12&years&of&the&project.&Afterwards&the&spot&price&is&multiplied&with&the&
yearly&power&production.&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
21&”Forudsætninger&for&samfundsøkonomiske&analyser&på&energiområdet&2011”:&Danish&Energy&Agency&
22&Appendix&F&V&NPV&

24. Group&3& & Semester&project&2014&
& Page 24 of 55&
Then&taking&the&tax,&which&is&20%&and&deduct&it&from&the&income.&&
Tax : 1752,02⋅106
DKK( )⋅20% = 350,4⋅106
DKK 3.8( )
(1752,02⋅106
−350,4⋅106
)DKK =1401,61⋅106
DKK 3.9( )
&
Then&the&expenses,&including&the&inflation,&will&be&deducted&from&the&rest&of&the&income,&and&then&we&
get&the&annuity:&
Expenses(N) = expenses⋅ 1+r( )
N
r = inflation
&
Expenses year1( )= 252,562⋅106
DKK( )⋅ 1+0,5%( )
1
= 253,825⋅106
DKK 3.10( )&
Expenses year 6( )= 288,807⋅106
DKK( )⋅ 1+ 0,5%( )
6
= 297,58⋅106
DKK 3.11( )&
Annuity year 1( )=1401,61⋅106
DKK − 253,825⋅106
DKK =1147,51⋅106
DKK 3.12( )&
Annuity year 6( )=1401,61⋅106
DKK −387,03⋅106
DKK =1103,76⋅106
DKK 3.13( )&
The&same&method&is&used&to&calculate&the&annuity&for&all&the&years.&Year&one&and&six&was&just&some&
examples.&
&
The&present&value&is&calculated&by23:&
P1 = A1
1+i( )
N
−1
i 1+i( )
N
=1147,51⋅106
DKK ⋅
1+ 5%( )
1
−1
5% 1+ 5%( )
1
=1092,87⋅106
DKK 3.14( )
&P6 =1103,76⋅106
DKK ⋅
1+ 5%( )
1
−1
5% 1+ 5%( )
6
= 823,64DKK 3.15( )
&
This&method&is&used&to&calculate&the&present&value&for&all&the&years.24&
&
The&sum&of&the&present&value&for&all&years&is&the&net&present&value,&it&is&2,2&billion&DKK&and&because&it&is&
positive,&the&project&is&viable.&
The&salvage&value&will&affect&the&NPV,&and&in&this&situation&it&will&affect&the&NPV&negative.&The&Salvage&
value&can&in&many&projects&be&positive&and&affect&the&NPV&for&a&project&in&a&positive&way,&but&because&
the&scrap&value&for&a&wind&turbine&is&so&high,&the&salvage&value&will&reduce&the&NPV.&Because&the&NPV&in&
this&project&is&so&high,&the&salvage&value&in&this&situation&will&not&affect&the&NPV&very&much.&Looking&at&
the&table&in&appendix25,&it&seems&that&the&salvage&value,&V52,7&million&DKK26,&will&reduce&the&NPV&by&
52,7&million&DKK.&&
&
With&the&function&“goal&seek”&in&excel&it&will&be&possible&to&find&the&interest&rate&of&return&because&if&the&
NPV=0&the&rate&of&return&is&called&the&interest&rate&of&return.&&
NPV i( )= 0
interest rate of return: i=7,71%&
This&means&if&the&minimum&attractive&rate&of&return&is&under&7,71%&the&project&will&be&a&good&
investment.&&
&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
23&Francis&M.&Vanek,&Louis&D.&Albright&and&Largus&T.&Angenent:&“Energy&Systems&EngineeringV&Evaluation&and&
Implementation”,&Mc&Graw&Hill&Education,&2.&Edition.&Page&81&
24&Appendix&F&V&NPV&
25&Appendix&F&V&NPV&
26&http://www.ens.dk/sites/ens.dk/files/undergrundVforsyning/vedvarendeVenergi/vindkraftV
vindmoeller/havvindmoeller/idriftsatteVparkerVnye/ErnstYoung%20baggrund_v_1%200.pdf&page&4&

25. Group&3& & Semester&project&2014&
& Page 25 of 55&
So&if&the&MARR>7,71%,&then&the&project&is&financial&viable.&There&are&three&main&reasons&to&set&a&good&
MARR.&The&first&reason&is&the&inflation,&the&MARR&have&to&be&over&the&inflation&if&the&company&wants&to&
earn&money&on&the&project.&In&Denmark&the&inflation&is&about&0,5%,&so&the&MARR&have&to&be&above&
0,5%.&Then&the&second&reason&is&an&alternate&investment,&which&means&that&the&rates&of&return&from&
available&alternate&investments&determine&the&baseline&acceptable&value&for&the&MARR.&The&last&reason&
is&the&risk.&A&risk&could&for&example&be&investing&in&new&unproven&technology.&Anholt&wind&farm&is&not&
the&first&offshore&wind&farm&in&Denmark.&Much&research&has&been&done&before&the&project&began,&so&the&
risk&is&not&very&high&at&that&point.&The&inflation&is&difficult&to&anticipate,&so&that&is&a&big&risk.&Another&
risk&could&be&the&power&production&each&year.&It&is&not&possible&to&tell&the&exact&yearly&power&
production.&With&these&factors,&a&good&MARR&could&be&5%,&because&it&is&still&lower&than&the&interest&
rate&of&return,&and&it&can&cover&all&the&factors,&which&was&listed&before.&&
&
&
The!NPV!is!positive!which!means!that!after!all!expenses!are!paid!the!value!for!Anholt!wind!farm!is!still!
worth!more,!so!project!would!make!a!good!deal.!With!a!MARR!on!5%!the!estimated!expenses!and!risks!
are!covered!and!the!NPV!is!2,24!billion!DKK.!!
!
!
It&is&now&safe&to&say&that&the&erection&of&wind&turbine&parks&is&financially&favourable,&but&construction&
cannot&yet&start.&First&multiple&things&need&to&be&taken&into&consideration,&one&of&them&being&the&
environmental&consequences,&both&positive&and&negative.&&
!
& &

26. Group&3& & Semester&project&2014&
& Page 26 of 55&
4(Analysis(of(environmental(aspects((
When&a&largeVscale&project&like&the&construction&of&a&wind&turbine&project&is&commissioned,&there&is&a&
large&number&of&things&that&need&to&be&taken&in&to&account.&One&of&the&areas&that&needs&a&thorough&
investigation&is&the&environmental&effects&on&the&surrounding&wildlife.&It&is&not&only&required&out&of&a&
moral&obligation&to&nature,&there&are&also&a&strict&set&of&rules&issued&by&the&government,&to&prevent&
habitat&destruction&and&the&loss&of&native&Danish&wildlife.&Even&though&this&seems&unnecessary,&as&it&
has&no&direct&effect&on&the&goal&of&erecting&the&park,&which&is&to&produce&green&energy,&it&is&a&key&part&of&
the&initial&research.&&This&is&because&the&Danish&government&has&set&strict&rules&on&the&research&of&the&
effects&on&marine&and&bird&wildlife&and&if&they&are&not&followed,&the&Danish&Energy&Agency&has&the&
authority&to&shut&down&the&project.27&This&means&that&the&environmental&research&conducted&in&the&
initial&faces&of&the&project&is&just&as&important&as&the&development&of&the&physical&outline&of&the&park,&
because&without&it,&the&project&will&not&be&approved.&&
4.1(Construction(period((
The&biggest&change&in&the&marine&environment&happens&during&the&construction&of&the&park.&During&
this&process,&a&lot&of&drilling&is&done&into&the&seabed&in&order&to&mount&the&turbines&to&the&seabed&and&
bury&the&power&cable&connecting&the&park&to&the&mainland.&In&this&process,&a&lot&of&sediment&is&moved&
around&and&the&native&flora&and&fauna&that&is&not&able&to&move&out&of&the&way&because&it&lives&in&or&is&
attached&to&the&seabed&will&die&from&being&dug&up&or&buried&in&the&left&over&sediment.&This&however&is&
not&affecting&a&very&large&percentage&of&the&animas&in&the&area&because&the&wind&turbines&are&located&
with&a&large&distance&between&them&e.g.&300V400m&for&Horns&Rev&1.&In&addition,&the&quantum&of&
biomass&in&the&sand&on&the&seabed&is&not&very&high&as&it&is&not&very&rich&of&nutrients.&However,&a&large&
amount&of&boulders&from&the&excavation,&making&space&for&the&foundations&of&the&monopoles,&has&been&
used&to&create&25&artificial&stone&reefs&in&the&area.&The&artificial&reefs&are&introduced&as&habitats&that&
provide&new&feeding&and&breeding&conditions&for&animals&and&fish&in&the&area&of&the&wind&farm.&&
Another&aspect&of&the&building&phase&that&has&a&larger&effect&on&the&marine&life&is&the&noise&produced&as&
the&pillars&are&drilled&into&the&ground.&This&courses&many&animals,&especially&mammals,&to&flee&the&area&
resulting&in&a&loss&in&biodiversity.&Research&has&shown&that&given&time,&when&the&building&process&is&
done&and&the&noise&is&gone,&animals&will&return&to&fill&in&the&missing&parts&of&the&food&chain.28&
&
4.2(Long(term(effects((
On&the&side&of&the&long&term&consequences&of&the&presence&of&a&wind&turbine&park,&the&only&thing&that&
has&caused&concern&for&some&people&is&the&vibrations&caused&by&the&rotation&of&the&blades,&being&
transferred&through&the&tower&and&into&the&water&disturbing&the&sensory&of&animals&using&
echolocation.&This&was&assessed&by&the&EIS&(Environmental&impact&Assessment)&and&shows&no&
significant&effect&on&the&communication&between&animals&in&the&area.&&
When&the&park&is&erected&however&and&it&is&producing&clean&energy&for&people,&it&is&also&bettering&life&
underneath&the&water&surface.&Introducing&concrete&pillars&up&to&10&meters&in&diameter&creates&an&
enormous&potential&for&the&increase&of&many&different&species.&A&good&example&is&the&common&clam,&
which&has&benefited&tremendously&from&the&park.&
& &
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
27&http://www.ens.dk/sites/ens.dk/files/undergrundVforsyning/vedvarendeV
energi/EIA%20Guidance%20Document%20final%20feb%202013.pdf&page&2&&
28&http://188.64.159.37/graphics/Publikationer/Havvindmoeller/kap04.htm&&

27. Group&3& & Semester&project&2014&
& Page 27 of 55&
&
!
!
!
!
!
!
!
! !
!
!
!!!!!!!!Fig.!4.1:!The!density!of!fish!expressed!by!the!!!!!!!!!!Fig.!4.2:!Common!mussels!tagging!over!the!structure!at!
!!!!!!!!distance!from!the!turbines,!at!Horns!Rev!1.!!!!!!!!!!!!Horns!Rev.!
!
The&introduction&of&the&pillars&has&given&them&a&hard&surface&to&grow&on&enabling&them&to&filter&the&
water&at&different&depths.&A&lot&of&other&animals&depend&on&hard&surfaces&to&grow&on&and&their&
presence&pave&the&way&for&other&species&further&up&the&food&chain&like&crabs,&fish,&birds&and&mammals&
extending&the&amount&of&biomass&in&the&area.&This&can&be&seen&on&the&graph&above&that&shows&that&the&
further&away&from&the&pillars&you&come,&the&smaller&the&amount&of&fish.29&&
&
4.3(Effect(on(birds(
(
(
(
&
&
&
&
&
&
&
Fig.!4.3:!Mean!orientation!(±!")!of!184!!!!!!!!!!!!!!!!!!!!!Fig.!4.4:!Mean!orientation!of!northward!bird!!
southbound!tracks!of!migrating!birds!recorded!!!!!!!!!migrations!at!Horns!Rev!during!spring!2004!
by!radar!north!of!the!wind!farm!in!spring!2004!!!!!!!!!based!on!a!total!of!1.316!bird!tracks!recorded!!
and!autumn!2003!in!relation!to!distance!to!the!!!!!!!!!by!radar.!!
wind!farm.!
&
A&research&program&has&been&made&in&connection&to&the&erection&of&Anholt&wind&farm,&to&find&out&more&
about&the&possible&bird&fatalities&when&they&migrate&through&the&area,&that&Anholt&wind&farm&is&located.&
In&general&there&has&not&been&an&increase&of&bird&deaths&in&the&area.&The&birds&are&clever&enough&to&fly&
around&the&turbines&as&shown&in&figure&4.430.&In&addition,&the&blades&on&the&turbines&rotate&at&a&speed&
so&"slow"&that&the&risk&of&a&bird&being&hit&by&flying&in&to&one&of&the&three&blades&is&close&to&none&existing.&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
29&http://188.64.159.37/graphics/Publikationer/Havvindmoeller/kap04.htm&
30http://188.64.159.37/graphics/Energiforsyning/Vedvarende_energi/Vind/havvindmoeller/vvm%20Horns%
20Rev%202/Horns%20Rev/fugle/horns%2520rev%25202004.pdf&Page&20&and&23.&&

28. Group&3& & Semester&project&2014&
& Page 28 of 55&
There&are&radars&placed&on&the&shore&of&Anholt,&as&well&as&on&the&shore&of&Jutland,&to&gather&the&
necessary&information&about&the&birds&migrating&through&Anholt&wind&farm.&
Studies&show&that&the&real&enemy,&when&it&comes&to&birds’&wellbeing,&is&windows&and&taller&buildings.&
4.4(Visual(impact((
The&recreational&value&of&Anholt&wind&farm&is&indeed&great.&When&the&general&population,&with&a&bit&of&
knowledge,&looks&at&the&farm,&they&will&get&some&kind&of&satisfaction&knowing&that&Denmark&is&working&
on&reducing&the&total&CO2Vemission&of&the&country&by&using&"clean"&energy&as&the&main&power&
contributor.&
The&placement&of&the&farm&helps&a&lot&when&talking&about&the&visual&effect&is&has&on&the&Danish&
landscape.&Had&the&wind&farm&been&onshore&the&potential&neighbours&might&not&have&liked&the&idea&of&
looking&at&a&wind&farm&with&111&units&every&single&day,&instead&of&look&at&the&beautiful&Danish&
countryside.&
As&of&right&now,&the&future&will&bring&more&wind&farms,&so&that&the&goal&of&cutting&the&total&Danish&CO2V
emission&down&by&40%&by&2020&compared&to&1990&will&be&a&reachable&one.&To&help&achieve&the&goal,&a&
wind&farm&called&Horns&Rev&3&is&being&erected&in&2017.&
&
4.5(Impact(on(the(overall(Danish(CO2(emissions((
The&goal&of&putting&up&wind&turbines&is&to&lower&the&overall&CO2&emissions&of&the&energy&production.&
The&wind&turbines&is&just&one&of&the&ways&of&achieving&independence&from&fossil&fuels,&but&just&how&
much&does&one&wind&turbine&park&matter&in&the&overall&account&of&the&Danish&CO2&emissions.&
V !!!!!"#$$%!%#&'!!"#!!"#$:!0,093
!
!"
31&
Horns&rev&2:&209&MW&
V !" = ! 209!" ∗ 3,6
!"
!"
∗ 4000!ℎ!"#$!32! = !3009600!!"!&&&(4.1)&
V 3009600!" ∗ 0,093
!
!"
= 279892,8!!"!!!!
!&&&(4.2)&
Anholt:&400MW&
V !" = (400!" ∗ 3,6
!"
!"
) ∗ 4000 = !5760000!"&&&(4.3)&
V 5760000!" ∗ 0,093
!
!"
= !535680!!"!!!!
!!!(4.4)&
&
To&get&an&idea&of&how&large&a&difference&it&makes&for&the&overall&CO2&emissions&to&install&the&two&parks,&
it&is&compared&to&the&emissions&of&2014:&&
Annual&emissions&for&2014&in&Denmark:&39.9&million&tons.33&
&
1 − (
39900000 − 535680 + 279892,8
39900000
∙ 100 = 2,04%!!!(4.5)&
&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
31&A&number&is&found&in&the&excelVdocument∈&table&8,&under&documents&in&the&link:&
http://www.ens.dk/info/talVkort/fremskrivningerVanalyserVmodeller/samfundsokonomiskeVberegningsV
forudsaetninger&&
32&The&number&is&a&given&value&of&full&load&hours&for&wind&turbines,&taken&from&the&first&assignment&in:&
energisystemer&og&miljøaspekter.&&&
33&https://eVlearn.sdu.dk/bbcswebdav/pidV3687954VdtVcontentVridV4891716_2/courses/ETVEEEEVU1V1V
E14/energistatistik2012.pdf&page&38&

29. Group&3& & Semester&project&2014&
& Page 29 of 55&
As&shown,&these&two&large&projects&only&have&a&small&impact&on&the&overall&Danish&emissions.&So&for&
Denmark&to&become&independent&form&fossil&fuels,&it&will&take&a&lot&of&projects&like&this,&and&that&does&
not&even&guarantee&for&the&production&to&exceed&the&demand,&because&of&the&fluctuations,&as&discussed&
later&in&the&assignment.&&&
(
&
&
&
(
&
&
&
&
&
&
&
Fig.!4.5:!Danish!CO2!emissions!from!1990!to!2022.!!!
!
As&visible&in&this&graph,34&the&initiatives&taken&by&the&government&to&decrease&the&CO2Vemissons&has&
had&a&positive&effect&because&of&projects&like&the&parks.&The&reason&why&the&prognoses&shows&an&
increase&in&the&amount&of&CO2&emitted&to&the&atmosphere&is&because&the&power&plants&in&the&future&will&
run&more&on&bioVfuel.&Materials&like&straw&and&wood&has&a&higher&CO2Vcoeficient&than&coal&but&it&is&still&
a&good&thing,&because&these&materials&has&absorbed&carbon&from&the&air&in&its&growth&period&and&is&
therefore&perceived&as&CO2&neutral.&This&lowers&the&overall&emission&by&not&having&to&burn&fossil&fuel&
that&took&carbon&from&the&air&millions&of&years&ago&and&puts&it&into&the&air&today.&&
&
How!much!CO2!can!be!saved!using!wind!turbines!
Turbine!size!! Production!pr.!year!!! CO2!saving!pr.!year!!
850!kW! 1842800!kWh! 1.445!tons!!
2,3!MW!land! 6900000!kWh! 5.410!tons!!
2,3!MW!sea!! 9200000!kWh! 7.213!tons!!
Table!4.1:!The!table!calculates!with!784g!for!1kWh!from!a!standard!coal!plant.35!
!
One&common&mistake&made&by&people,&is&that&wind&turbines&are&100%&free&of&CO2&emissions.&That&is&
not&the&case,&because&both&the&production&and&removal&process&requires&machines&and&so&on,&that&
emits&CO2.&Therefore&it&is&interesting&to&look&at&the&amount.&If&the&CO2&emitted&during&the&entire&life&of&
the&turbine&is&spread&out&over&the&amount&of&kWh´s&it&produces,&it&is&possible&to&compare&it&to&other&
forms&of&energy&production.&To&do&this,&a&useful&tool&is&a&lifecycle&analyses&(LCA).&If&the&LCA&for&a&wind&
turbine&is&compared&to&a&LCA&for&a&power&plant,&the&turbine&emits&only&5&g&of&CO2&pr.&kWh&and&a&power&
plant&emits&600&g&pr.&kWh.&Because&the&turbines´&production&is&120&times&smaller,&it&is&attractive&and&
necessary&to&change&from&one&type&of&production&to&the&other.&The&savings&pr.&Wind&turbine&compared&
to&a&coal&plant&is&shown&in&the&table&above.&&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
34https://www.energinet.dk/SiteCollectionDocuments/Danske%20dokumenter/Klimaogmiljo/Udvikling%20i%
20emissioner%20af%20CH4,%20N20,%20CO,%20NMVOC%20og%20partikler%201990V2022.pdf&page&6.&&
35&http://www.dkvind.dk/fakta/m2.pdf&&page&3.&&

30. Group&3& & Semester&project&2014&
& Page 30 of 55&
4.6(Disposal(
The&disposal&of&offshore&wind&turbines&is&done,&by&cutting&the&pole&at&about&1&meter&into&the&seabed.&
The&part&of&the&pole&that&is&placed&in&the&seabed&and&stands&about&25&meters&deep&is&kept&there,&
whereas&everything&above&the&seabed&is&transported&to&at&location&where&most&of&it&is&recycled.&The&
link&(a&transistor)&that&connects&the&poles&in&the&seabed&to&the&poles&above&has&an&expected&lifetime&of&
40&years&and&it’s&expected&to&be&reused&when&the&turbine&is&replaced.&&
The&biggest&issue&regarding&the&disposal&of&a&wind&turbine&is&the&blades.&There&is&a&partially&solution&to&
the&problem&where&the&fibre&enforced&plastic&from&the&blades&are&recycled&in&the&production&of&cement.&
The&wings&are&crushed&to&small&crumbles&that&are&mixed&into&cement.&The&final&result&is&a&substance&
that&can&be&used&by&cement&manufactures&to&replace&fuel&like&coal&and&also&as&raw&material&to&create&
concrete.&&
Regarding&disposal&of&turbine&blades,&there&are&3&scenarios.&First&scenario&is&as&above,&where&100&%&of&
the&blades&are&deposited.&Second&scenario&is&a&total&burning&of&the&blades&without&an&eventual&recycling&
of&the&materials.&The&last&scenario&suggests&a&90&%&recycling&of&the&material&without&including&a&
reprocess&of&the&materials.&10&%&of&the&materials&are&deposited.&The&total&energy&consumption&for&the&
three&scenarios&are&not&that&different,&as&shown&in&the&picture&below.&The&only&thing&worth&mentioning&
is&that&the&volume&of&the&disposal&is&relatively&high&by&using&scenario&1.&
&
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Fig.!4.6:!environmental!effects!of!different!scenarios!of!disposal.36!!
&
On&their&website,&Vestas&claims&that&almost&everything&from&the&wind&turbines&are&recycled.&Only&
plastic&and&concrete&are&nonVrecyclable&and&is&therefore&driven&away&and&disposed&otherwise.&In&the&
appendix&a&table&showing&how&much&of&the&individual&materials&can&be&recycled.&
&
The!expansion!in!the!amount!of!wind!turbines!build!will!have!an!effect!on!the!environment!both!
regarding!CO2!emissions,!animals!and!sea!life.!However,!the!research!into!the!consequences!is!extensive!
and!it!has!yielded!the!implications!negligible.!In!addition,!when!compared!to!the!consequence!of!
proceeding!on!the!path!of!a!fossil!fuel?based!supply,!wind!energy!is!the!better!and!necessary!choice.!!!
&
Now&that&all&the&environmental&concerns&has&been&taken&into&account&and&the&project&is&not&in&the&risk&
of&being&rejected&by&the&Danish&Energy&Agency,&it&needs&to&be&put&into&the&broader&context&of&the&entire&
Danish&power&grid&and&the&effects&of&supplying&the&grid&with&wind&energy.&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
36&“Livscyklusvurdering&af&vindmøllesystemer&og&deres&anvendelse”:&Henriette&Hassing,&Miljø&page&14V15&

31. Group&3& & Semester&project&2014&
& Page 31 of 55&
5(The(current(Danish(power(grid(towards(2020(
The&Danish&power&grid&had&to&go&through&a&dramatic&change&back&in&the&1970’s&because&of&major&oil&
crises.&What&this&change&did&to&the&Danish&power&grid&is&elaborated&in&the&appendix.37&
5.1(The(functionality(of(the(power(grid(
With&the&production&of&electricity&in&Denmark&today,&which&is&quite&fluctuating&because&of&wind&energy,&
the&power&grid&needs&to&be&in&constant&balance.&The&balance&is&between&power&production&and&power&
consumption,&and&whereas&this&task&was&easier&when&the&decentralized&thermal&power&plants&
dominated,&the&task&of&keeping&the&grid&in&balance&is&much&more&complicated&now.&&
Those&responsible&for&keeping&things&running&smoothly&in&Denmark&energyVwise&are&Energinet.dk.&
They&use&different&tools&to&keep&energy&flowing&into&the&houses,&factories&etc.&in&Denmark.&&
Primarily&they&use&production&planning&to&keep&things&in&balance.&Production&planning&uses&supply&and&
demand&to&find&out&what&the&next&24V36&hours&will&be&like&on&the&power&grid.&These&data&are&found&on&
Nord&Pool&Spot&and&a&supply&and&demand&curve&is&made.&From&the&supply&and&demand&curve&
Energinet.dk&can&compose&a&plan&of&operation.&&
If&the&wind&blows&more&or&less&than&expected&and&the&wind&turbines&generate&more&or&less&energy&than&
there&is&being&used,&Energinet.dk&uses&liabilityVpartners&to&either&increase&or&decrease&energy&
production&or&usage.&That&is&how&they&manage&the&balance&in&the&power&grid&if&deviations&from&the&
original&production&plan&appear.&&
To&ensure&a&steady&supply&on&the&energyVmarket,&Energinet.dk&purchases&energy&reserves,&which&is&
used&to&regulate&the&market.&If&a&situation&occurs&where&the&supply&cannot&keep&up&with&the&demand,&
the&reserves&are&used&to&balance&out&the&lacking&supply.&The&reserves&are&divided&into&two&different&
kinds,&fast&reserves&and&slow&reserves.&The&fast&reserves&have&to&be&able&to&be&activated&within&seconds,&
where&slow&reserves&are&activated&between&15V90&minutes.&&
&
The&Danish&power&grid&is&under&constant&surveillance&by&Energinet.dk.&This&means&that,&if&errors&or&
unbalances&in&the&stability&of&the&power&grid&occur,&they&can&regulate&and&balance&the&grid&at&a&cheaper&
price.&A&key&element&for&Energinet.dk&is&early&notifications&of&possible&irregularities&in&the&grid.&
Therefore&a&control&centre&tries&to&predict&what&might&happen&in&the&system&concerning&usage&and&
production&of&electricity.&This&is&where&sustainable&energy&such&as&wind&turbines&can&be&a&challenge,&
because&of&the&constant&changes&in&weather&conditions.&Precise&predictions&are&therefore&necessary&to&
prevent&greater&fluctuations&in&the&power&grid.&&
&
Although&it&can&be&a&nightmare&to&control&and&regulate&the&Danish&power&grid&regarding&sustainable&
energy&sources&and&its&fluctuations&because&of&the&weather,&there&is&a&bright&side&to&fluctuating&
elements&in&the&power&grid.&The&Danish&power&grid&has&connections&to&its&neighbours&and&hence&an&
increased&possibility&to&export&the&overproduced&electricity.&This&way&the&value&of&the&extra&electricity&
is&increased&for&the&reason&that&the&electricity&is&not&traded&back&in&to&the&Danish&market.&&
In&general&the&interaction&between&fluctuating&power&production&and&waterVreserves&in&Norway&and&
Sweden&is&good.&The&reserves&acts&like&a&large&battery&and&can&be&used&to&even&out&irregularities&in&the&
power&grid.&Information&about&storage&is&found&in&section&6.2.&&&
&
&
& (
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
37&Appendix&H&–&The&Danish&power&grid&towards&2020&

32. Group&3& & Semester&project&2014&
& Page 32 of 55&
5.2(Security(of(supply(in(the(power(grid(
Energinet.dk&and&ens.dk&uses&the&following&definition&of&security&of,&“The&probability&that&there&is&
power&to&the&consumers&when&they&need&it”.&But&there&is&no&real&definition&of&the&security&of&supply.&
Not&even&the&power&supply&legislation&has&a&precise&definition&on&the&matter.&&
&
Security&of&supply&is&measured&by&how&many&minutes&each&individual&consumer&has&been&without&
power&within&the&period.&This&means&that&Denmark&has&a&security&of&supply&at&99,991%&implying&that&
each&consumer&has&been&without&power&in&45&minutes.&Some&users&can&have&been&without&power&for&
several&hours&where&others&might&not&have&had&any&power&loss&during&the&period.&&
&
&
Fig.!5.1:!Minutes!without!power!per!1?24!kV!supply?point!per!year.!!
V Grey:!Outside!own!area!
V Orange:!Force!majeure!in!own!area!
V Green:!Planned!in!own!area!
V Purple:!Follow?breaches!in!own!area!
V Blue:!Errors!in!own!area!
The!graph!shows!how!many!minutes,!in!average,!each!consumer!was!without!power!in!the!period!1990?2011.!The!
numbers!are!covering!the!gross!amount!of!disconnections!whether!they!occurred!due!to!errors!in!the!local!
distribution!net!or!the!power!grid.!!
For&further&information&on&how&the&Danes&are&affected&by&power&cuts,&see&appendix.38&&&
&
Towards!the!year!2020!the!production!of!electricity!from!wind!turbines!will!increase!from!30%!to!above!
50%.!This!is!going!to!change!the!requirements!of!the!Danish!power!grids!flexibility.!The!power!grid!will!
not!have!to!have!the!same!amount!of!capacity!from!power!plants!in!the!future!as!it!has!now.!Flexibility!on!
other!power!plants!will!be!necessary!as!backup!and!for!regulating,!if!disconnections!of!different!units!
occur!in!the!power!grid.!The!plants!will!not!have!to!be!located!in!Denmark!but!can!be!located!in!
neighbour!countries!where!the!Danish!power!grid!is!connected.!!
In!the!future!the!power!grid!can!develop!in!to!a!system!where!there!is!no!need!for!national!capacity!from!
the!power!plants.!!This!will!only!be!the!case!if!it!is!show!to!be!more!economical!attractive!to!the!Danish!
society!to!use!flexible!power!plants!located!in!other!countries!than!Denmark.!
!
!
Now&that&it&has&been&established&that&the&stability&of&the&grid&is&changing&because&of&the&transition&to&
renewables,&it&is&necessary&to&know&what&this&will&do&to&the&energy&prices,&and&how&it&is&possible&
increase&stability.&&&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
38&Appendix&H&–&Security&of&supply&