European Offshore Wind 2009

2009 09 15 | Kriegers Flak Wind Farm | Göran Loman | PYP 1

European Offshore Wind 2009

Conceptual Foundation Study

for Kriegers Flak

Göran Loman, Vattenfall

Thomas Stalin, Vattenfall

Helge Gravesen, Grontmij | CarlBro

or

A Marathon race in 15 minutes


Participants in the project

• Ballast Nedam• Cowi• GrontMij|Carlbro• ISC AS• MT Højgaard• MT Piling• Per Arsleff AS• Pihl & Søns AS• Rambøll• SGS• Skanska• Vattenfall

Financed by Vattenfalls project Kriegers Flak Wind Farm and by the Swedish Energy Agency


Vattenfall Windpower

Vattenfall • Owned by the Swedish government

Activities• Today

– DK, FI, DE, NL, PL, SE, UK, – 2 TWh/a– One of the leading generators

in the Nordic countries– Significant share of the world

offshore market

• Development– Seven ongoing large projects under

construction– Several under development

• Goal– Climate neutral 2050 (Vattenfall group)


Kriegers Flak Wind Farm

• 30 km south of Trelleborg

• 17-40 m water depth

• 128 plants

• Each 5 MW

• 2.6 TWh/y


The scope of work

Aims

• Evaluate existing kinds of foundations

• Develop more cost efficient concepts

Project development

• Open seminar in February 2008presentation of concept

• Some ten consultants and contractors where engaged

• The experts work with design

• Evaluation of fabrication, installation, costs

• Adjustments and final design

• Final presentation at EOW

• Final report

Regular meetings where the concepts where discussed and evaluated


Actual site assessment was used

• Geotechnical surveys

• Fino2

• Hydrographic measurements


The concepts

• Foundations

– Steele monopile

– Steele quadroped

– Concrete gravity

– Concrete gravity tripod

– Concrete monopile

• Sea bed preparation robot


Steel monopileRambøll and MT Højgaard

• Conventional design

• Suitable conditions for monopile

– Drilling needed where boulders occur

• 3.1 M€ (35 m, 5 MW)

– More compatible at shallow depth

• Limited storage area needed


Steele quadropedRambøll and MT Højgaard

• Design

– Concrete transition piece

– 2 levels of X-braces

• Less wave load

• 3.0 M€ (35 m, 5 MW)

– More competitive at deeper water

• Possibilities for further optimisations


Steele quadropedInstallation


Concrete gravity Cowi and Aarsleff

• Three designs– Conventional cone– Floating (KIS)– Semi floating

• Conventional– Cost effective, 2.4 M€ (35 m, 5 MW)– Durable and robust– Maintenance friendly– Heavy lifting floating cranes

• Floating– The floating concept need more

concrete and deeper harbour– KIS 4 M€, semi floating 3 M€– No heavy lifting floating crane– Could be improved


Concrete gravity triopod ISC and Skanska

• Design

– Three legs, triangular shape

– Standardised parts

– Prefab elements, in situ casting

– Total installation concept

• Heavy (>3,000 tons)

• Expensive 3.8 M€ (35 m, 5 MW)

• Need to be improved


Concrete monopileBallast Nedam and MT Piling

• Design

– Prefab concrete monopile

– Vertical drilling

• Concrete

– Less expensive than steel

– High fabrication capacity

• No uw noise or vibration during installation

• Unproven technique (or?)

• 3,1 M€ (5 MW, 40 pc)

– 2 M€ for 130 pc


Stone bed preparation robot, Pihl

• No divers needed

• One stop for

– Soil investigation (vibro cores, CPT)

– Final levelling of the sea bed

– Surface measurements

– Creating the stone bed (fall pipe)


Summary

• Several interesting concepts were evaluated and improved

• There is a potential for further optimization

• Need to iterate with turbine suppliers

The foundations, you don’t see them, but you need them!


Kriegers Flak Wind Farm

More information:

www.vattenfall.com/kriegersflak

European Offshore Wind 2009

Documents

Transcript of European Offshore Wind 2009