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Offshore wind technology, possibilities and trends

Madsen, Peter Hauge; Rasmussen, Flemming; Hjuler Jensen, Peter

Publication date:2009

Link back to DTU Orbit

Citation (APA):Madsen, P. H. (Author), Rasmussen, F. (Author), & Hjuler Jensen, P. (Author). (2009). Offshore windtechnology, possibilities and trends. Sound/Visual production (digital)

https://orbit.dtu.dk/en/publications/5202152e-e340-497e-9f27-655eee0f36fa

Offshore wind technology, gy,possibilities and trends

Peter Hauge MadsenFlemming RasmussenPeter Hjuler JensenPeter Hjuler Jensen

Presented at Risø International Energy Conference 2009

Population centres often at the coast

17/04/2008Presentation name2 Risø DTU, Technical University of Denmark

Abundant resourceAbundant resourceEU27 power from the North Sea


The wind pits of Europe – The North Sea

E ll t i d•Excellent wind resources 10‐11 m/s average

50-100mm/s average

•Manageable water depths

25 50m

p

•Large population densities around it 25-50m

•Vast in size


Available areas - Plans for future offshore wind f i D kfarms in Denmark

• Status 2008 3163 MW 423 • Status 2008 – 3163 MW, 423 MW offshore

• 2009-2012 additional 840 MW offshoreMW offshore

• Report on future Offshore sites, Update of action plan from 1997

• 23 Sites each 44 km2 for a capacity of 4600 MW Wind PowerP d ti 18 TWh j t • Production 18 TWh, or just over 8% of total energy consumption in Denmark or approximately 50% of Danish approximately 50% of Danish electricity consumption


World market for wind energy – 2008 World market for wind energy 2008

Installed Wind Power in the World- Annual and Cumulative -

30,000 150,000

GLOBAL STATUS

20,000

25,000

ar

100,000

125,000

MW

GLOBAL STATUS• 28 GW installed in 2008• 122 GW installed in total

1% ff h 2008

10,000

15,000

MW

per

ye

50,000

75,000

Cum

ulat

ive • ~1% offshore 2008

• ~3.4 % offshore 2013• ~22 % in EU 2020 (40/180

MW)

0

5,000

1983 1990 1995 2000 2008

Year

0

25,000

Source: BTM Consult ApS - March 2009

MW)• 1.3 % of global electricity• Power-consumption

growing 3 3% per yearpdat

e 2008

growing 3.3% per year• Wind power growing 25%

per year• Installed power doubles

rld M

arke

t U

p Installed power doubles every 3 years

• Factor 10 in ~10 years• Goal 2020: 12 %, 1200


Wor Goal 2020: 12 %, 1200

GW

d l i

Short term

Key development issuesDanish MEGAVIND Strategy -June 2008

ffShort term• Cost• Reliability, maintainability,

avaliability

Offshore technology, aiming to:

– develop new concepts for electricalinfrastructure in offshore wind farms

y• Design conditions and process• Validation• Grid integration

– develop design procedures for the turbine, support structure and foundations to reducedesign uncertainty

– develop and optimze concepts for foundationsGrid integration

Medium to long-term• Cost

develop and optimze concepts for foundationsand installation, focusing on depths > 15m

– develop condition monitoring and data acquisition systems to map fault accorences

• Cost• Design methods• Upscaling• Larger waterdepth

and optimize O&M

– improve access and safety

– improve knowledge of geotechnics and • Larger waterdepth• Grid integration• New concepts

geophysics

– develop knowledge on materials with focus oncorrosion


– develop optimal O&M strategies

Costs - Offshore wind farms

Wind Energy – The Facts, EWEA, 2009


Why Offshore Wind Differs fromTraditional Offshoread t o a O s o e

• Offshore Wind Turbines Characteristics– Highly dynamic responseg y y p– Strict eigen frequency requirements– Actively controlled load response– Wind and wake effectsWind and wake effects– Undamped cross-wind vibrations

• Design Considerations– 50-year return period on extreme event50 year return period on extreme event– Wind load dominated (water depth?)– Overall fatigue driven (incl. low cycle)

• Traditional Offshore Structures:• Traditional Offshore Structures:– Passive in their load response– 100-year wave load dominated

Build in structural redundancy– Build-in structural redundancy


Beatrice Offshore Wind Turbine - UK

Wind loads dominated by wake effects

CFD – Large eddysimulation


Influence of wind and wave directionality onfatigue loads at the mudlinefatigue loads at the mudline

1.5

1.2

1.3

1.4

omen

t ran

ge

0 8

0.9

1

1.1

norm

alis

ed e

quiv

alen

t mo

0.5

0.6

0.7

0.8

1 H

z n

0 10 20 30 40 50 60 70 80 90

Wave misalignment [deg]

dMx dMy

Normalised equivalent bending moment t th dli (f 0 33 H )ranges at the mudline (f=0.33 Hz)


Grid integration - Power fluctuations –2 casescases

800

400

500

600

700

wer

(MW

)

HRBHRA

Horns Rev B

Horns Rev A

Djursland Anholt O

Djursland Anholt P

0

100

200

300Pow HRA

HR2HR1Horns Rev

Horns Rev 2

Time

28/1-2000 29/1-2000 30/1-2000 31/1-2000 1/2-2000

800

400

500

600

700w

er (M

W)

DAPDAO

Horns Rev B

Horns Rev A

Djursland Anholt O

Djursland Anholt P

0

100

200

300Pow HR2

HR1Horns Rev

Horns Rev 2

Horns Rev A


Time

28/1-2000 29/1-2000 30/1-2000 31/1-2000 1/2-2000

Connection of offshore wind farmsConnection of offshore wind farmsRadial or meshed

Tradewind - Integrating Wind, Developing Europe’s power market for the large-scale integration of wind power, February 2009


Kriegers Flak new concept for offshore Kriegers Flak – new concept for offshore wind farm connection

Both transmission of power to land grid and exchange of powerexchange of power

Advantages:

Optimal regional economy

Improvement of market

Added security of supplyAdded security of supply

Demonstration of new technology

Pil t j t f th N th Pilot project for the North sea


Developments and innovationDevelopments and innovation

• Upscaling• Soft foundations• Floating• Combined wave and wind• Vertical axis

Gravity causes steadyloads

Aerodynamic loads are~cyclic


UPWIND – EU Integrated project

Objective:Objective:Develop improved design models and verification methods for wind turbine components

• Very Large Wind Turbines

• More Cost Efficient Wind Turbines

• Offshore wind farms of • Offshore wind farms of several hundred MW


Up-ScalingThe wind turbines have 200820082008

250 m Ø

The wind turbines have increased in size – despitephysics

??????????????

Jos BeurskensJos Beurskens

Repower

Jos Beurskens

Repower

Jos Beurskens


WG 4 Foundations and support structuresstructures


UPWIND: Foundations and support structuressupport structures

Monopile Jacket Floating sparMonopile…..Jacket…..

Floating spar


Compliant structures: How do they work?

Design structure such Design structure such that:

Sw(ω)

1st

mode

2nd

mode

–1st mode ‘below’ wave spectrum

[m2s]

spectrum

–2nd mode ‘above’ wave 2 mode above wave spectrum 0

0f [Hz]

31.40

T [s]

0.03 0.06 0.10 0.13 0.16 0.19 0.22

15.7 10.5 7.9 6.3 5.2 4.5 [ ]


Concepts for compliant support structures for offshore wind turbines

??

Slender Guyed tower Buoyant towerArticulated

buoyant towerTower with mass trap

Compliant piled tower


Monopiley y y p

b S il dHYWIND concept by StatoilHydro

• 2-5MW pitch controlled windturbineturbine

• Floating spar bouy attached to three mooring lines

• Intended for water depths between120 – 700m.

• Demonstration project withSiemens 2.3MW 10km outside westcoast of Norway.


i ll iHYWIND concept - installation

• HAWC2 was used for the design loads.

• Coupled version of HAWC2 pand SIMO/RIFLEX

• Stand-alone edition of HAWC2


Focus on the HYWIND concept: Vibration Focus on the HYWIND concept: Vibration modes.New vibrations mode occurs for the floating concept1. Horizontal translation (2 modes)0.01Hz2. Rigid body rotation, tilt (2modes) 0.035Hz3 Vertical translation 0 037Hz3. Vertical translation 0.037HzThese modes are more low frequent than the dominating

wave excitation.

F i il h t bi th l tFor a similar on-shore turbine, the lowestNatural frequency is1st tower bending 0 4Hz1 tower bending 0.4Hz


SWAY concept• Downwind rotor• Wire construction to limit tower

load• Single tension leg (Stiff in Single tension leg (Stiff in

torsion)• Special joint bearing to avoid

b di i t i lbending in tension leg• Yaw bearing between tower

bottom and tension legg• Tower shape with non-circular

shapeG a it an ho s stem• Gravity anchor system


Blue H – the first floating turbineBlue H the first floating turbine

• Demonstration project 10km from coast of Italy ongoing• Very sparse information available, but turbine is small and y p ,

construction huge . . .


id C bi d d i dPoseidon – Combined wave and wind

• Wave energy platform• Dimensions are very

large. Three turbines canproduce extra power produce extra power from wind – and contribute to the total damping of motiondamping of motion.


Poseidon


Poseidon: Simulation results

Ongoing work:Ongoing work:

- HAWC2 is coupled to WAMSIM (Code for floating vessel motion, DHI)

- Full aero/hydro/structure simulation for floating platform with threeb l d


turbines are simulated.

Unlimited ressource for offshore wind energy

Conclusions

• Unlimited ressource for offshore wind energy• Rapid growth in installations• EU promotion of offshore developmentEU promotion of offshore development• Engineering challenges• Grid integration of offshore wind a challenge and an

f hopportunity for the power system• Offshore development the key driver for wind power

technology developmenttechnology development• Deep water concepts under way

• Offshore wind is just at the beginning – all options areopen


Thank you for your attentionThank you for your attention


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