new concepts for installing windturbines offshore

NEW CONCEPTS FOR INSTALLING WINDTURBINES OFFSHORE


all-in-one offshore turbine installations

les installations éoliennes offshore tout compris

Dolf Elsevier van Griethuysen

Ballast Nedam Offshore Energy

Nieuwegein, The Netherlands

Marseille, Jeudi 19 Mars 2009

Co authors

Edwin van de Brug

Marcel van Bergen

Jurjan Blokland

Ballast Nedam Offshore

Nieuwegein, The Netherlands


Tradition in developping installation concepts:HLV Svanen installing Confederation Bridge, Canada

Tradition in developping installation concepts:HLV Svanen installing Wind turbine Foundations at Egmond, NL

Tradition in developing installation concepts:HLV Svanen installing Wind turbine Foundations in UK

And also a tradition in installing gravity based foundations

HLV Svanen installing offshore wind farm foundations:

• 2006: 36 x at Egmond, The Netherlands

• 2008: 25 x at Rhyl Flats, UK

• 2008/2009: 32 x at Gunfleet Sands, UK

• 2010: 22 x at Baltic I, Germany

New concepts for installing Windturbines Offshore

Present Concepts

for

installing Windturbines


Present Windturbine installation method

Other concepts in development

The Challenges


Challenges in the emerging market of offshore wind:

• political, financial and logistic constraints,

• grid access,

• weather conditions,

• increasing water depths.


Challenges in the emerging market of offshore wind:

• political, financial and logistic constraints,

• grid access,

• weather conditions,

• increasing water depths.

And:

• more powerful and lager turbines

• with the subsequent need for larger installation equipment


Technical challenge I

The concept of present-day installation equipment, mainly jack-ups, is limited by its own inherent contradiction:




• on the one hand lifting capacity should be as extensive as possible




• on the one hand lifting capacity should be as extensive as possible

• on the other hand the soil pressure of the legs should be kept as low as possible.


The Jack Up internal constraint: lifting capacity vs leg pressure

The Jack Up internal Constraint: lifting capacity vs leg pressure

Technical Challenge II

For the installation of some of today’s largest offshore turbines, a one-lift concept has been successfully used, involving the deployment of a floating crane


Technical Challenge II

For the installation of some of today’s largest offshore turbines, a one-lift concept has been successfully used, involving the deployment of a floating crane

Still, operations remain time-consuming and weather, wave and wind-sensitive.


The first all-in-one offshore turbine lift, Beatrice, UK

Using a Sheer Leg or an A-frame has the disadvantage of ‘multiplying effects’ on the movement of the vessel, or barge in larger displacements of the load carried by the hook of the crane.


Using a Sheer Leg or an A-frame has the disadvantage of ‘multiplying effects’ on the movement of the vessel, or barge in larger displacements of the load carried by the hook of the crane.

Lifting the load in the centre of gravity of the crane vessel will substatially reduce this effect


Displacements standard Sheerleg or Crane Vessel

Displacements when load is in centre of gravity

In order to meet the need for suitable and efficient equipment in installing increasingly larger and powerful turbines, new concepts have to be developed if the offshore wind energy sector wishes to contribute to the European targets set with respect to renewable energy.


In the floating crane concept optimum use can be made of water forces.

• A solution should be sought to maintain maximum stability combined with maximum lifting capacity, as required.

• And the problem to be solved is how to control acceleration forces at ‘touch-down’,


Ballast Nedam has developed a concept to control touch-down operations in a one-lift concpt with a floating crane.

The result is a combination of a soft-landing and holding device.

The principle behind the controlled operation is that before touch-down the tower will be indirectly connected to the foundation with a device that introduces a pre-stressed connection which compensates the accelerations during touch-down.


Thus, it is possible to install the heaviest and largest wind turbines in one single controlled and wave-independent operation.


The greatest advantage demonstrated by our concept is not primarily formed by the mere installation costs themselves,



but much rather the fundamental fact that the one-lift concept is actually possible and feasible;




that the entire commissioning and testing process can be completed onshore,




that the entire commissioning and testing process can be completed onshore,

and finally that we have decreased the number of weather, wave and wind-sensitive operations to be held offshore.


This presents a truly revolutionary step in risk mitigation

and thus in cutting back overall costs


Ballast Nedam

Innovation:

The One Lift Concept


PRESS RELEASE Ballast Nedam, 13 March 2009

“BN has developed a frame that enables the heavy lift vessel Svanen to pick up complete heavy windmills in the harbour, transport them to the offshore location, and then install them on site.

This development renders unnecessary the assembly of wind turbines from multiple modules in expensive and risky offshore time.”


Technical details

AnimationOne Lift Concept

Another and recent Innovation:

The Drilled Concrete Monopile


PRESS RELEASE Ballast Nedam, 13 March 2009:

“The technical feasibility of a drilled prefabricated concrete pile as an offshore wind turbine foundation has been demonstrated.

The advantages of this foundation are:

• Reduced noise levels (no percussion),

• lower manufacturing costs,

• greater price stability of concrete compared with steel.”


Drilled (concrete) monopiles, based on existing technologies

(Drilled) concrete monopiles, based on existing technologies

The pile will be built up from vertically poured ring elements which are stored vertical to avoid ovalization and are assembled horizontally.

Drilling and installing of a concrete monopile

Step 10: Continue drilling until target level is reached.

Drilling and installing of a concrete monopile with HLV Svanen

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www.ballast-nedam.com


merci beaucoup

new concepts for installing windturbines offshore

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