Installation, commissioning and decommissioning offshore wind

Marcus Bentin

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Faculty of Maritime

Studies

Weiter

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Maritime Industry in Germany

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Installation of offshore wind turbines

• In 2015 3,230 offshore wind turbines in the EU (11,027 MW)

• New installation of 759 offshore wind turbinesin the EU (3,019 MW) in 2015

• Installation of offshore wind turbines is large market sector

• Dismantling or repowering after 20-25 years(by law)

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Installation of offshore wind turbines in Germany

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Installation of offshore wind turbines in Germany

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Commission of Windpark Riffgat in Germany from EWE

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Dismanteling of offshore wind turbines

not so much experiences could be gained yet

2016 Yttre Stengrud, Vattenfall (5 turbines each 2 MW)

http://www.maritime-

executive.com/article/first-offshore-wind-

farm-decommissioning-complete

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Key problem

• Most wind farms (in Germany) are founded in deep water several seamiles off the coast

• Long trip for the workers from the coast to thewind farms

• Often small time windows of good weather

• As yet no established processes fordismanteling

• Sometimes not even established laws andregulations

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Key problem

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Key problem

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Principle decommissioning processsuggested by Rhenus

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Today proposed methods for decomission

• The today proposed methods have there roots in the onshore wind sector, offshore oil and gas industry and the experience from the erection processof the offshore wind farms

• One principle is to do most of the decommission process onshore. The offshore operations are costly and have to be minimized

• The difference to oil and gas is:– there are many smaller sized structures in the field that have to be removed instead of

one big platform. Hence the tools might be oversized?

– the water depth is usualy less than 50m in Germany it can be more

– the distance to the coast is usualy less than 50 miles, in Germany it can be more

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Today proposed methods for decomission

• The operations can be clustered for:

– Wind Turbines

• lift operations

– Fundation of Turbines, Substation, Met Mast

• Cut and lift operations

– Offshore Substation

• Lift operation

– Cables Inter-array/Export

• Cut and remove or left in situ

– Onshore Cables, Substation (wedo not focus here)

e.g. Topham

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Used Literature

• Eva Topham*, David McMillan: “Sustainable decommissioning of an offshore wind farm” in Renewable Energy 102 (2017) p. 470-480

• Gillian Smith, Chris Garrett & George Gibberd: “Logistics and Cost Reduction of Decommissioning Offshore Wind Farms” presented at EWEA Offshore 2015 10 - 12 March 2015, Copenhagen

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Operations for Turbine

• First the turbine has to be prepared todecommission, powerless,– Cut electric cable

– Dismantel Nacelle

• Heavy lift operation around 600t (Rotor and Nacelle)

• Dismantele rotor from nacelle on thedeck of the vessle otherwise it has to bedone before?

https://cdn1.pri.org/sites/default/files/styles/story_main/publi

c/story/images/BIWF%20Tower%201%20complete.jpeg?itok=l

n86I6_z

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Operations for Tower and Transition piece /Monopile

• Most productive way would be liftingTower and Transition piece together withthe foundation– Therefore cutting of foundation only from

outside

– Lifting of 1500t and later even more

http://www.4coffshore.com/windfarms/images/

articles/4/image4(1).jpg

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Operations for Fondations /Monopile

• First the pile has to be inspected (ROVs)

• Score protection has to be removed for cutting?– The effort depends on the protection type

• Cable has to be cut and burried in ground. (ROV, diver)

• Excavation with sea trencher

• Crane hooks are positioned to the lifting points

• The piles are cut below seabed and have to be monitored afterwards

• Removing entire structure??? As alternative

http://www.4coffshore.com/windfarms/images/

articles/4/image4(1).jpg

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Operations for Score protection

• The hope is that it can be left in Situ– But today you cannot realy be sure in

Germany if the general rule is applied everything has to be left as it was before

– Argumentation: new marine habitat, removalwould distroy the habitat

– If they have to be moved productive ideas arenecessary otherwise it is done with a grapperdiver or ROV assistance

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Operations for Cables

• The hope is that they can be left in Situ– If the burial depth of the inter-array and

export cable is deeper than 1m.

– They are cut and removed where they come up less than 1m

• Cut operation with ROV???

• Towed on a drum on board the vessel

• The buried cables have to monitored during years.

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Operations for Offshore Substations

• Here know how of the oil and gas industry is available as well as technology.

• Platforms already have to be removed

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Available Technology for the Operations

• Cutting technology:– Hydraulic shears for cable

– Abrasive wire cutting or abrasive jet cuttingfor 80mm and more wall thickness and over5m diameter

http://miragemachines.com/files/cache/fa500

1c62306763e2a02ab1cdea6b797_f792.jpg

http://www.oceaneering.com/wp-

content/uploads/2013/03/Conductor-Cut-

Pic.jpg

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Available Technology for the Operations

• Logistic and heavy lift operations:– Several offshore vessels from the oil and gas

industry

– Wind park erection vessel, Jack Up Vessels, Heavy Lift Vessels

Project Idea:

Offshore Wind Decommissioning Toolbox for the North Sea Region

Project Titel:

Eco-innovative concepts for the end of offshore wind

energy farms’ lifecycle

Isabel Sünner

Interwork Event, Göttingen, 29.6.2017

Background and Relevance

Offshore wind industry mainly focuses on setting up new

projects

Only little attention is given to decommissioning

It is foreseeable that 50 offshore wind farms will need to be

dismantled until 2038

Hamburg Institute of International Economics (HWWI) Slide 25

Central aim:

is to develop new processes and working tools to organize

the decommissioning of offshore wind energy parks in an

environmentally safe and cost-effective way

Aspects to be considered:

• Economic and legal framework

• Impact on regional development

• Impact on environment

• Requirement profile for new working tools /

operations

• Logistical concepts, including material and

personal resources

• New vessel type

• Recycling / disposal of components

Hamburg Institute of International Economics (HWWI) Slide 26

Envisaged output

• Logistical concepts including material and personal

resources (using a model of wind energy plants)

• Concept for recycling / disposal of particular components

• Definition of requirements for a new vessel type

• Environmental and safety analysis of the new tools

• Exploitation plan for the new tools

• Impact analysis on regional development

Hamburg Institute of International Economics (HWWI) Slide 27

Hamburg Institute of International Economics (HWWI) Slide 28

Isabel SünnerHamburg Institute of International Economics (HWWI)International cooperation and project development

suenner@hwwi.org

Please get in contact!

• Business / Industry Partners (from all over the NSR)

• Cluster organisations in the field of offshore wind (particularly

from BE, DK, NL, UK)

Potential partners

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Project Partners

Confirmed:

• University of Applied Sciences Emden-Leer, Germany

• HILOG, Institute for Logistics, Emden, Germany

• Port of Oostende, Belgium

• Flanders Maritime Cluster, Belgium

• HWWI, Germany

• Energy Valley, Netherlands

• WPT Winschoten, Netherlands

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Possible fonds Interreg North Sea Region (www. http://www.northsearegion.eu)