1. OO Star Wind Floater A robust and flexible concept for floating wind
Trond Landbø
Presentation April. 2013

2. Dr.techn.Olav Olsen AS – Innovative Company2 2

3. Design Experience – Offshore Wind Foundations
Offshore Wind Sub-Stations
Concrete foundations
Steel Foundations
Foundations for Offshore Wind Turbines
Concrete Foundations
Floating Wind Turbines
Hywind (Spar)
Semisub Design
TLP Design
Foundation Base Solutions
Piles
Gravity Base
Suction Bucket 3 3

4. OO Star Wind Floater – Basis for development
Floating Offshore Wind - Existing concepts
- Limited amount of existing concepts. Many of them seems non-realistic.
WindSea
Ideol
Blue H TLP
HYWIND
Sway
WindFloat
Dr.techn.Olav Olsen – Development of OO Star Wind Floater
- Demand for cost effective and realistic concepts – “Simple, Safe, Robust and Cost Effective”
OO Star
Hybrid Semi
HIPRWind
Steel Semi
OO Star
Concrete Semi
OO Star
Steel Semi

5. OO Star Wind Floater – General Description
The OO Star is a robust, stable and very simple floater concept.
Water depth potential from 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.

6. OO Star – Tuning of geometry
The following main parameters can be adjusted to fulfil requirements with regard to motions and stability:
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
Full concrete floater with extended base slab

7. OO Star Wind Floater – Why Concrete ??
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.

8. 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.

9. 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

10. First phase hydro dynamic analyses
OO Star Wind Floater
First phase hydro dynamic analyses
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
FLOATGEN - SIMO simulation

11. First phase structural analyses
OO Star Wind Floater
First phase structural analyses
FEA to evaluate stress distribution in shaft/ pontoon interface
Used for establishing a sound connection detail during conceptual design.

12. 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: (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: (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

13. Thank You for Listening !