ewea wp21 dec 01 - offshore wind energy · Nordex N60 1300 Stall reg., fixed speed 60 Nordex N80 (offshore) 2000 Pitch reg., variable speed 80 1.33 Bonus 1300 (land) 1300 Active stall,

Colin MorganColin Morgan

Garrad Hassan & Partners Ltd

www.garradhassan.com

Garrad Hassan & Partners Ltd

www.garradhassan.com

Concerted Action on Offshore Wind Energy in EuropeState of the art - offshore wind turbine technology

Contract No. NEE5/1999/562


Funded by the European Commission

CA-OWEE ProjectCA-OWEE Project


17 European Partners from 13 Countries:

Principal partners:

• Delft University of Technology, NL (co-ordinator)

• Garrad Hassan & Partners, United Kingdom *

• Kvaerner Oil & Gas, United Kingdom *

• Energi & Miljoe Undersoegelser (EMU), Denmark

• Risø National Laboratory, Denmark

• Tractebel Energy Engineering, Belgium


17 European Partners from 13 Countries:

Other Contributors:

• Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Spain

• Centre for Renewable Energy Sources (CRES), Greece

• Deutsches Windenergie-Institut (DEWI), Germany

• Germanischer Lloyd Windenergie, Germany *

• Netherlands Energy Research Foundation (ECN), The Netherlands

• Espace Eolien Developpement (EED), France

• Ente per le Nuove Tecnologie, l'Energia e l'Ambiente (ENEA), Italy *

• University College Cork, Ireland

• Vindkompaniet i Hemse AB, Sweden *

• Technical Research Centre of Finland (VTT), Finland *

• Baltic Energy Conservation Agency (BAPE), Poland

Objective:

“to define the maturity of the technology currently available for offshore wind farms”

Objective:

“to define the maturity of the technology currently available for offshore wind farms”


Scope:Scope:

l Offshore wind turbine size and configuration

l Support structure

l Installation, decommissioning and dismantling

l Operation and maintenance, reliability

l Electrical transmission and grid connection

l Offshore wind turbine size and configuration

l Support structure

l Installation, decommissioning and dismantling

l Operation and maintenance, reliability

l Electrical transmission and grid connection


Wind turbine size and configurationWind turbine size and configuration

1. Scaling trends

2. Control

3. Rotor blades

4. Gearboxes

1. Scaling trends

2. Control

3. Rotor blades

4. Gearboxes


Growth of the technologyGrowth of the technology

0

500

1000

1500

2000

2500

1988 1990 1992 1994 1996 1998 2000 2002

kW

Offshore

Onshore Germany

Power rating trend - up to 62m rotor diameter

Power rating trend - up to 62m rotor diameter

P = 0.0664D 2.43

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60 70

rotor diameter, D [m]

ratedoutput

power P [kW]

….. with larger machines….. with larger machines

P = 0.1215D2.23

0

500

1000

1500

2000

2500

3000

0 10 20 30 40 50 60 70 80


rate

d ou

tput

pow

er, P

[kW

]

P = 0.1215D2.23

0

500

1000

1500

2000

2500

3000

0 10 20 30 40 50 60 70 80


rate

d ou

tput

pow

er, P

[kW

]

Design blade tip speedDesign blade tip speed

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70 80 90

rotor diameter [m]

blad

e ti

p sp

eed

[m/s

]

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70 80 90

rotor diameter [m]

blad

e ti

p sp

eed

[m/s

]

Increasing tip speedIncreasing tip speedDesign Power

[kW]Controlconcept

Tip speed[m/s]

Ratio(offshore/land)

Vestas V66 (land) 1650 Pitch reg.,variable slip

66

Vestas V80 (offshore) 2000 Pitch reg.,variable speed

80

1.21

Nordex N60 1300 Stall reg.,fixed speed

60

Nordex N80 (offshore) 2000 Pitch reg.,variable speed

80

1.33

Bonus 1300 (land) 1300 Active stall,fixed speed

62

Bonus 2000 (offshore) 2000 Active stall,fixed speed

68

1.10

NEG Micon 1000/60 (land) 1000 Stall reg.,fixed speed

57

NEG Micon 2000/72 (offshore) 2000 Active stall,fixed speed

68

1.19

Control system trendsControl system trends

l Pitch controlOnly around half of models historicallyPredominant in turbines over 70m diameter

l Variable speedLess than 10% of models historically are fixed speedDual-speed; high slip; moderate range variable speed; direct drive systemsSome form of variable speed predominant in large machines

l Pitch controlOnly around half of models historicallyPredominant in turbines over 70m diameter

l Variable speedLess than 10% of models historically are fixed speedDual-speed; high slip; moderate range variable speed; direct drive systemsSome form of variable speed predominant in large machines

Blade technologyBlade technology

y = 0.2699x2.3448

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

0 10 20 30 40 50 60 70 80

rotor diame te r D, [m]

blad

e w

eigh

t [k

g]

GearboxesGearboxes

l Rotor speed approx. 20rpm; generator speed approx. 1500rpm

l Historically, 3 stage - 1 planetary, 2 parallel

l Larger machines likely to require 4th stage (>3MW onshore, larger offshore due to higher rotor speed)

Marked increase in complexity, or,

Increased generator speed, or,

Direct drive approach

l Rotor speed approx. 20rpm; generator speed approx. 1500rpm

l Historically, 3 stage - 1 planetary, 2 parallel

l Larger machines likely to require 4th stage (>3MW onshore, larger offshore due to higher rotor speed)

Marked increase in complexity, or,

Increased generator speed, or,

Direct drive approach

Future trendsFuture trends

l Higher tip speedsLower torque, less mass and cost of tower top

l Increased carbon fibre usageHigher specific strength if solidity is to be maintained

l Direct driveLess mechanical complexity

l Increasingly integrated designSupport structure

Grid connection (e.g. HVDC generator)

Design for installation & maintenance

l Higher tip speedsLower torque, less mass and cost of tower top

l Increased carbon fibre usageHigher specific strength if solidity is to be maintained

l Direct driveLess mechanical complexity

l Increasingly integrated designSupport structure

Grid connection (e.g. HVDC generator)

Design for installation & maintenance

Support structuresSupport structures

Monopile expected to be most common option for future offshore wind projects (but probably least stiff)

Monopile expected to be most common option for future offshore wind projects (but probably least stiff)

Monopile Piled-BracedMonotower

GBS-BracedMonotower

GBSMonotower

GBS-LatticeTower

Monopile designMonopile design

Well-established codes and practices (oil and gas)Structures typically supported by 3 or 4 legs

Single pile through each leg“Skirt” piles around each leg

But, unlike an offshore platform,Turbines exert much higher live loads (shear and bending)Cyclic loading of near-surface soils more importantPotential for loss of soil contact near surface (post-holing)

Much higher volume jobs (I.e. not one-offs)

Nearshore works practice (jetties, etc.) important reference

Well-established codes and practices (oil and gas)Structures typically supported by 3 or 4 legs

Single pile through each leg“Skirt” piles around each leg

But, unlike an offshore platform,Turbines exert much higher live loads (shear and bending)Cyclic loading of near-surface soils more importantPotential for loss of soil contact near surface (post-holing)

Much higher volume jobs (I.e. not one-offs)

Nearshore works practice (jetties, etc.) important reference

Monopile installationMonopile installation

Four options:Above-surface hammeringUnderwater hammeringDrill-driveDrill and grout

Trade-off:Installation speedRequired pile capacityGeotechnical knowledgeRisk of damage to pileRequired placement accuracy

Four options:Above-surface hammeringUnderwater hammeringDrill-driveDrill and grout

Trade-off:Installation speedRequired pile capacityGeotechnical knowledgeRisk of damage to pileRequired placement accuracy

www.offshorewindenergy.orgwww.offshorewindenergy.org


Acknowledgement: EC funding & 17 partnersAcknowledgement: EC funding & 17 partners

ewea wp21 dec 01 - offshore wind energy · Nordex N60 1300 Stall reg., fixed speed 60 Nordex N80 (offshore) 2000 Pitch reg., variable speed 80 1.33 Bonus 1300 (land) 1300 Active stall,

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