Current Offshore Wind Energy Technology and Deployment Activities Robert Thresher National Renewable Energy Laboratory National Wind Technology Center, Director Operating Agents Jørgen Lemming Walt Musial Supported by Sandy Butterfield and Flemming Øster IEA Offshore Wind Energy

IEA stands for the International Energy Agency IEA is an energy forum for 25 industrialised countries established in Since 1977 undertaken collaborative R&D projects approved as annexes through more than 40 Implementing Agreements. Headquarters in Paris What is IEA

Currently 23 Members from 21 Countries, plus the EU Commission and EWEA (as sponsor) Collaboration tasks based on national wind energy programmes in the member countries. Strategic plans for long term R&D needs Annual Reports (national programs and overviews). IEA wind web site: IEA Wind Energy

Annex 11Technology Information - Topical Expert Meetings and Joint Action Symposia's. Annex 19Wind Energy in Cold Climates. Annex 20Advanced Aerodynamic Modeling Annex 21Dynamic models of wind farms for power system studies Annex 23Offshore Wind Energy Technology and Deployment Annex 24Integration of Wind and Hydro Systems Annex 25Cost of Wind Energy (not approved yet) Ongoing and new Annexes

Annex XXIII Offshore Wind

CountryMembership Status/ Contracting Party Organization United StatesCommitted/US Department of Energy NREL  MIT  University of Massachusetts  GE Energy DenmarkCommitted/RISØ National Laboratory RISØ National Laboratory  Vestas  Elsam  Carlbro NorwayCommitted/Enova SF  NTNU-BAT United KingdomComitted/Department of Trade and Industry  Garrad Hassan  Ceasa NetherlandsCommitted  ECN GermanyCommitted  University of Stuttgart  GE Energy South KoreaCommitted  Inha University FinlandTBD  VTT SwedenTBD  Chalmers JapanTBD  MITI Annex 23 Participation

Ecological Issues and Regulations [[ Suggested areas of collaboration: Baseline data and research methods Impacts on the environment (assessment criteria) Experience and application of Environmental Impact Assessments  Summarize preliminary conclusions from EU COD project.  Potential cumulative effects to the marine ecology  Conclusions from avian and mammal surveys Permitting processes  Streamlining planning and approval procedures  Educating the regulators and facilitating interagency cooperation Pre- and post-construction monitoring of operating wind facilities Public (stakeholder) involvement and acceptance Decommissioning processes and procedures

Grid Integration First meeting held in Sept 2005, Manchester UK The five critical issues to be included in the work plan:  Offshore wind meteorology and impact on power fluctuations and wind forecasting  Behavior and modeling of high-voltage cable systems  Grid Code and security standards for offshore versus onshore  Control and communication systems of large offshore wind farms  Technical architecture of offshore grid systems and enabling technologies. Next Meeting: In Planning. Draft work plan was sent to members last month for comment. Members will narrow focus to most critical issues.

External Conditions, Layouts and Design of Offshore Wind Farms Suggested areas of collaboration: Exchange, validate, and evaluate wind resource data and wind maps specific to regions with high potential for wind development. Share databases and innovations to enhance measurement accuracy of marine buoys pertaining to long-term sea-state and MET-Ocean data. Technical exchange of wave loading methods and validation experience of wave loading on wind turbine structures. Share experience with long-term measurement techniques and instrumentation at offshore stations. Layout and array effects (Energy production, mutual shadow effects of large, closely spaced farms) New turbine and foundation designs for shallow water facilities

External Conditions, Layouts and Design of Offshore Wind Farms First Meeting Held at Risoe Dec 2005 Three working groups were formed: 1) Wake modeling and benchmarking of wake models 2) Marine boundary layer characteristics 3) Met-ocean data and loads Wake modeling subgroup will meet May31-June 1. 1) Step: Workshop on status existing works 2) Step: Workshop on evaluating the quality of models and results Other sub-group meetings are being planned.

Modeling wakes

Measured Wake losses at Horns Rev Wind Direction

2) Marine boundary layer characteristics To investigate the marine boundary layer defined as the lowest ~1 km of the atmosphere above the wave surface of the ocean. To review current experience particularly with regard to developing wind farms in coastal areas (~50 km from the coast) To assess the reliability of remote sensing methods offshore including satellite observations, sodar and lidar, where the aim is to observe wind and turbulence profiles at 100 m and above and to include tall mast measurements where available To assess the accuracy of model predictions including local scale, mesoscale and LES models as available.

What is the Wind Speed = ?? Neutral Boundary Layer Convective Boundary Layer Stable Boundary Later with Low Level Jet Graphic Credit: Bruce Bailey AWS Truewind 2) Marine boundary layer characteristics

Wake loss Assessment at Horns Rev European Remote Sensing Satellite -2 Global Measurements and Images including Sea State, Sea Surface Winds, Ocean Circulation, and Sea and Ice Levels.

3) Met-ocean data and loads Turbulent winds Irregular waves Gravity / inertia Aerodynamics:  induction  skewed wake  dynamic stall Hydrodynamics:  scattering  radiation  hydrostatics Elasticity Mooring dynamics Control system Fully coupled

Scope Code Comparisons for: Wave loading Support structures Geotechnical Coupled system dynamics Goal 1.Quantify offshore load prediction capability 2.Identify critical modeling deficiencies common to all codes. Offshore Code Comparison: Collaboration (OC3) Lead: Sandy Butterfield-US DOE/NREL

Work done Baseline models complete (rotor, aerodynamics, controls, tower, turbulence model, wave kinematics) Basic turbine dynamics comparison complete. Support structure models defined but not complete Geotechnical model defined by not complete

Status: Phase 1.1: Baseline Model dynamics Comparisons (8 codes)

Planned Work Phase I (monopile) complete by June Phase II (quadropod) complete by December 2006 Phase III (floating) complete by May codes in comparison Participating countries institutions:  NREL (US)  Risoe (DK), Vestas (DK), Siemens (DK), Elsam (DK), DNV (DK)  Garrad Hassan (UK)  GL Windenergie (DE), Stuttgart (DE)  NTNU (NO) Next Meeting: June 8-9, 2006 Pittsburg

Annex 23 Summary Current Status: 4 research areas are planned with 3 making good progress starting the second year (4 year time line) Active collaborative technical working groups are formed with seven countries currently participating and three pending