OO Star Wind Floater

A robust and flexible concept for floating wind

Trond Landbø

Presentation April. 2013

Dr.techn.Olav Olsen AS – Innovative Company

Design Experience – Offshore Wind Foundations

• Offshore Wind Sub-Stations• Concrete foundations• Steel Foundations

• Foundations for Offshore Wind Turbines• Concrete Foundations• Steel Foundations

• Floating Wind Turbines• Hywind (Spar)• Semisub Design• TLP Design

• Foundation Base Solutions• Piles• Gravity Base• Suction Bucket

Floating Offshore Wind - Existing concepts- Limited amount of existing concepts. Many of them seems non-realistic.

Blue H TLP HYWIND Sway WindFloatWindSea

HIPRWindSteel Semi

Dr.techn.Olav Olsen – Development of OO Star Wind Floater- Demand for cost effective and realistic concepts – “Simple, Safe, Robust and Cost Effective”

OO StarConcrete Semi

OO StarHybrid Semi

OO StarSteel Semi

OO Star Wind Floater – Basis for development

Ideol

OO Star Wind Floater – General Description

• The OO Star is a robust, stable and very simple floater concept.

• Water depth potential from 50-60 m (subject to environment)

• Can be built in concrete, steel or a combination (hybrid). Material selection according to optimal design, cost, fabrication facilities etc.

• Concrete material typically for harsh environment, large turbines

• Steel typically for small/medium turbines, more benign waters

• Combination of concrete and steel to fulfil special requirements

• The OO Star consists of a central shaft supporting the WTG, and a tri-star shaped pontoon supporting 3 buoyancy cylinders for optimal stability.

• In principle the permanent buoyancy is in the columns and shaft. The pontoons provide structural support of the bucket cells, weight stability, added mass and temporary buoyancy for inshore assembly.

• The OO Star can be fabricated in a dock, on a barge or on a quay. The structure is well suited for modular fabrication.

• The full substructure can float with very small draft and the unit can be fully assembled at quay-side before tow to site. No requirements for deep waters or expensive heavy lifting offshore.

OO Star – Tuning of geometry

The following main parameters can be adjusted to fulfil requirements with regard to motions and stability:

Full concrete floater with extended base slab

• Draft

• Centre distance columns

• Diameter bucket cells and shaft

• Pontoon width, variations along pontoons

• Pontoon height, variations along pontoons

• Bilge keel – extension of base slab

• Compartments in corner cells

• A concrete version of OO Star is robust and flexible, can be sized for large turbines by changing simple parameters

• Concrete hull - clean and simple configuration

• Simple ballast system, piping from central shaft

• Optimal structural stiffness and dynamic characteristics

• Not fatigue sensitive

• Maintenance free hull

• Long design life, 100+ years (reusable)

• For a concrete floater the elevation for the interface between substructure and tower can be adjusted upwards to reduce fatigue in the steel tower.

OO Star Wind Floater – Why Concrete ??

OO Star Wind Floater – Why Concrete (contd.) ??

• Potential for low production cost through mass production and industrialization, worldwide

• Build-up of “new” supply chain different from offshore- and shipyards

• Local content, can be fabricated anywhere

• High number of potential fabricators can build these units (relatively low tech.) – improved competition

• Environment friendly

• So far OO Star has been developed for 3 MW and 6 MW WTG. Can be sized for 10 MW or larger.

OO Star Wind Floater – Why Steel ??

• Industry culture in particular countries

• Steel yard availability and efficiency

• Ship type structure – stiffened plates

• Lighter structure, simple handling inshore

• Very shallow draft inshore

• Suitable for small or medium size turbines

Hydrodynamic analyses by WADAM and SIMO to calculate heave and pitch periods in addition to floater response

Used for tuning of conceptual design by calibrating spread sheet calculations

OO Star Wind FloaterFirst phase hydro dynamic analyses

FLOATGEN - SIMO simulation

FEA to evaluate stress distribution in shaft/ pontoon interface

Used for establishing a sound connection detail during conceptual design.

OO Star Wind FloaterFirst phase structural analyses

OO Star Wind Floater – Ongoing Activities

• OO Star Wind Floater – Concrete• Concrete semisubmersible wind floater, 6 MW WTG

• Supported by Research Council of Norway

• Total budget 9 MNOK, RCN grants 4,5 MNOK

• Schedule: 2013-2014 (2 years)

• Project owner: Dr.techn.Olav Olsen AS

• Partners: IFE Kjeller, Statoil and Acciona

• Scope: Develop Basic Design for North Sea conditions

• FLOATGEN – Steel • Steel semisubmersible wind floater, 3 MW WTG

• EC-project with total budget 36 M€, EC grants 19 M€

• Schedule: 2013-2016 (4 years)

• Project split in two parts: Gamesa windfloater and Acciona windfloater

• Partners in Acciona group: Acciona, Navantia and Olav Olsen

• Scope: Design, build and install a floating wind turbine, demo unit in Spanish waters in 2016

• OO-scope: Develop floater technology, detail design of floater

Thank You for Listening !