IEC TC88 : Wind turbines Republic of Korea

Outline New Proposal of Korea Status of the WTs in Korea Roadmap of an On/Offshore WTs in Korea Design & Motion Analysis of the FOWT Conclusions

New Proposal of KOREA Title Scope Standard for Floating Offshore Wind Turbine(FOWT) Title Scope Purpose • To provide uniform methodology for assessment of the floating offshore wind turbine. • Assessment of design, analysis, installation and maintenance of FOWT for a various types. This work will aim to bring together expert knowledge from the wind energy and offshore engineering industries in order to formulate a guideline specification of the design, analysis, installation and maintenance requirements for FOWT.

New Proposal of KOREA CONTENTS 8.2 Type of hulls 1 Scope 2 Normative references 3 Terms and definitions 3.1 Terms 3.2 Definitions 4 Symbols and abbreviated terms 4.1 Symbols 4.2 Abbreviated terms 5 General requirements 5.1 Fundamental requirements 5.2 Safety requirements 5.3 Basic considerations 6 Design requirements 6.1 Introduction 6.2 General 6.3 Structural Categorization 6.4 Design criteria 6.5 Accidental loads 7 Environmental criteria 7.1 Environmental condition 7.2 Wind, waves, current 7.3 Water depth 7.4 Ice 7.5 Soil conditions 7.6 Marine growth 7.7 Earthquakes 7.8 Scour 7.9 Other environmental conditions 8 Floating offshore wind turbine structure design and analysis 8.1 Introduction 8.2 Type of hulls 8.3 Hydrostatic stability 8.4 Hydrodynamic response analysis 8.5 Structural design and strength analysis 8.6 Fatigue analysis 8.7 TLP design and analysis 8.8 SPAR design and analysis 8.9 Barge design and analysis 8.10 Other hulls design and analysis 9 Mooring system design and analysis 9.1 Fundamental requirements 9.2 Safety requirements 9.3 Design situations 9.4 Design criteria 9.5 Anchoring systems 9.6 Corrosion 9.7 Fatigue life 9.8 Strength and fatigue analysis 10 Fabrication, installation, inspection and maintenance 10.1 Introduction 10.2 Structural fabrication 10.3 Mooring system fabrication 10.4 Transportation 10.5 Installation operations 10.6 Inspection and testing 10.7 Maintenance and repair 11 Materials, welding, and corrosion protection 11.1 Introduction 11.2 Steel 11.3 Corrosion protection system 11.4 Nonlinear materials 12 Reference

Global WIND ENERGY 2000-2030 (in GW) Offshore 40 GW Offshore 150 GW Source : EWEA Global offshore wind trend

Economics of Fixed type vs. floating type Source : OTC

Resource of Wind Turbine in Korea Classification Unit Onshore Offshore Theoretical Potential TWh/y 987 881 Capacity GW 369 309 Area km2 97,545 79,539 Geographical 99 176 37 62 9,755 15,908 Technical 49 88 18 31 4,877 7,954 Water depth[m] Wind velocity[m/s] Energy density[W/m2] Wind energy(offshore<20m depth) Source : KIER Wind Map v1.1

Status of Wind Turbine Market in Korea • Period of 3-5 years in Wind turbine will invest 9 million dollar annually by Korea Government. • Technology development plan for the future Market -“Development of floating offshore wind turbine systems” selected as Strategic Technology by Korea Government • A distribution plan 2.25GW through Wind turbine by 2012. -3MW, 5MW offshore wind turbine development • Various offshore wind farm Investment Agreement in progress (MOU). Company Location Capacity Timeframe(year) KUMHO industrial. Jeonnam Yeosu city ￦2000 billion KOSPO(Korea southern power co.ltd) Busan city 350 MW KHNP (Korea hydro & nuclear power co.ltd, Doosan) Jeju city 30MW DONGKUK S&C Jeonnam Shinan(Bigeum-island) 90MW Target by 2013 POSCO Jeonnam Southwestern Sea 600MW Target by 2015 HANWHA E&C Incheon-City Muui-Do(Island) 2.5 MW * 39 1step by 2012

Status of Wind Turbine Market in Korea Installed wind farm Being installed wind farm Nanjido 100 kW KIER 100 kW Saemangeum 7,900 kW Wolryeong 100 kW Hangyeong 22,700 kW Woljung 1,500 kW Haengwon 9,795 kW Seongsan 20,000 kW Hoengseong 40,000 kW Angang 30,000 kW Daegwanryeong 102,890 kW Daegiri 2,750 kW Ulleung-gun 600 kW Taebaek 6,800 kW Yeongyang 18,000 kW Yeongdeok 39,600 kW Pohang 660 kW Miryang 750 kW Gori 750 kW Installed 277,995 kW Yanggu 20,000 kW Yanggu 19,500 kW Gyeonggi 3,000 kW Ansan 3,000 kW Nuaeseom 7,500 kW Taean 267,500 kW Saemangeum 22,500 kW Sinan 300,000 kW (1st 3MW) Jindo 100,000 kW Samdal 20,000 kW Deokcheon 40,000 kW Hangyeong 30,000 kW Dongbuk 20,000 kW Cheongsuri 3,000 kW Gapado 27,000 kW Gangneung 25,000 kW Daegiri 40,000 kW Pyeongchang 19,800 kW Jeongseon 50,000kW Donghae 60,000 kW Seokbo-myeon 160,000 kW Gimcheon 200,000 kW Sajapyeongwon 110,000 kW Prospect WTs 1,630,000 kW Sangdo 31,500 kW Nansan 14,700 kW Pyosyeon 20,000 kW Godeok 20,000 kW Yangsan 8,000 kW

R&D Roadmap of Wind Turbine in Korea Onshore System Large scale Wind Farm Development Site Searching Component Analysis and Design Component Localization and Export Site testing & Supplying Medium Sized Systems Pioneering abroad Market for components 750kW – Site test 2MW – Site test Offshore wind turbine Component Design 10kW Manufacturing Large Offshore wind farm Searching Hybrid System Development 10kW-Site test Large scale Offshore Wind Farm Development Supply Small Sized Systems Pioneering abroad market for Components Wind farm Construction in Asia 2MW – Design and Manufacturing 2MW Remodeling and Manufacturing 5~6MW Design and 3MW – Concept 3MW Design and 3MW – Site test 100kW-Site test 100kW Design and 5~6MW – Site test Multi MW class Offshore Wind turbine Supply Pioneering abroad market Main Target Offshore Small Medium sized System Commercialization / Component Development Large System Development /Component Localization and Expert Large System Export/ Commercialization of Application technology 1st Stage 2004~2007 Technology development and Industrialization 2nd Stage 2008~2012 Technology Accumulation 3rd Stage 2013~2018 Creating new Industry

Analysis Models(Plan) Model No. 1 2 3 Platform Type TLP Spar Barge Stabilized by Tether Tension Ballast Buoyancy Position Keeping Taut Catenary Slack Catenary

Conceptual Design Framework Design Basis Basic Requirement - Turbine Capacity, Motion Requirement Environmental Condition - Water depth, Wind, Current, Wave, Ice etc Hydrodynamic Data - Wind Load, Current Load - Motion Analysis : Motion RAO, Force Transfer Function Time Domain Analysis - Platform Motion : Angular Displacement, Acceleration - Mooring Line Tension Initial Design Hull Sizing Mooring System Loading Condition Stability Check Prediction of Motion Characteristics Hydrodynamic Analysis Structural Analysis Global/Local Strength Fatigue Analysis

Analysis Methodology & Procedures STEADY ENVIRONMENTAL LOADS DESIGN ENVIRONMENTAL CONDITION VESSELS LOW FREQUENCY MOTIONS STATIC MOORING SYSTEM DISPLACEMENTS AND TENSIONS VESSELS WAVE FREQUENCY MOTIONS TIME DOMAIN LINE TENSIONS DAMAGE CONDITION (incl. TRANSIENT) ANALYSIS ? CRITICAL MOORING LINE REMOVED DYNAMIC CONDITION ANALYSIS ? ANALYSIS COMPLETED DYNAMIC STUDY YES NO

Design Basis Rotor Environment (survival) Nacelle Mass(ton) Tower Diameter [m] Maximum RPM Maximum Tip Speed [m/s] Shaft Tilt [degree] Rotor Mass [ton] Nacelle Mass(ton) Tower Height [m] Diameter – bottom [m] Diameter – top [m] Thickness – bottom [mm] Thickness – top [mm] Mass [ton] Overall CoG Location (above tower bottom, m) X Y Z Environment (survival) Significant Wave height Wind Speed Water Depth Current Speed Tide Topsides Platform Weight Topside Weight Draft Motion Maximum Angular Motion Tower Top Acceleration

Design Basis of WT Platform Horizontal Motion Limits Rotational Motion Limits Acceleration Limits Simple Geometry Minimizing Heave Motion Pretension Offshore Platform Type = ? Number of Mooring Lines Displacement

TLP Type Total Weight Topside weight Steel Weight Fixed Ballast Displacement Draft VCG VCB GMT,L Radius of Gyration (@ COG) Rxx Ryy Rzz Mooring Line Characteristics No. of Line Dia. Elasticity Modulus MBL

Results – Motion time Series(TLP)

SPAR Type Total Weight Topside weight Steel Weight Fixed Ballast Displacement Draft VCG VCB GMT,L Radius of Gyration (@ COG) Rxx Ryy Rzz Mooring Line Characteristics No. of Line Dia. Elasticity Modulus MBL

Results – Motion time Series(SPAR)

Characteristics of floating offshore WT for each types TLP Type TLP Horizontal Motion, surge mode, has to be improved to meet excursion limitation which is generally 5% of water depth in offshore field Vertical motions are too good to be true Motion criteria, especially acceleration at the location of nacelle will be needed at the early design stage KG is higher than KB SPAR Type SPAR Permanent eccentricity is to be counter-balanced by the arrangements of the fixed ballast Simple structure KB is higher than KG Lowered KG by fixed ballast

Conclusion • At present, the technology of a floating offshore wind turbine is not established and studying continuously. • Experts need to create a new standard to compare the calculation data of floating offshore wind turbine for various load cases. • A new standard should be dealt with by experts separately(>IEC 61400-3)

Thank you!