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

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

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

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

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: 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

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.

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

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

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.

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

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