Current Offshore Wind Energy Technology and Deployment Activities

Robert ThresherNational 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 1974.

• 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: www.ieawind.org

IEA Wind Energy

Annex 11 Technology Information - Topical Expert Meetings and Joint Action Symposia's.

Annex 19 Wind Energy in Cold Climates.

Annex 20 Advanced Aerodynamic Modeling

Annex 21 Dynamic models of wind farms for power system studies

Annex 23 Offshore Wind Energy Technology and Deployment

Annex 24 Integration of Wind and Hydro Systems

Annex 25 Cost of Wind Energy (not approved yet)

Ongoing and new Annexes

Annex XXIII Offshore Wind

Annex 23 Operating AgentsRisø and NREL

Subtask 1 (Risø Lemming/Øster)Experience with critical deployment issues

Subtask 2 (NREL Musial/Butterfield)Technical Research for deeper water

Research Area # 4 -Offshore Code Comparison

CollaborationSandy Butterfield - USA

Research Area # 1Ecological Issues and Regulations

TBD

Research Area # 2Electrical System Integration

John Overton - UK

Research Area # 3External Conditions, Layouts and

Design of Offshore Wind FarmsJoergen Lemming - DK

Country Membership Status/Contracting Party

Organization

United States Committed/US Department of Energy

• NREL MIT University of Massachusetts GE Energy

Denmark Committed/RISØ National Laboratory

• RISØ National Laboratory Vestas Elsam Carlbro

Norway Committed/Enova SF NTNU-BAT

United Kingdom Comitted/Department of Trade and Industry Garrad Hassan

Ceasa

Netherlands Committed ECN

Germany Committed University of Stuttgart GE Energy

South Korea Committed Inha University

Finland TBD VTT

Sweden TBD Chalmers

Japan TBD 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

0.001

0.010

0.100

1.000

10.000

100.000

0.01 0.10 1.00 10.00Omega (rad/s)

P-M (m^2/(rad/s))

JONSWAP (m^2/(rad/s))

Kaimal ((m/s)^2/(rad/s))

Wind and Wave Spectra

0.001

0.010

0.100

1.000

10.000

100.000

0.01 0.10 1.00 10.00Omega (rad/s)

P-M (m^2/(rad/s))

JONSWAP (m^2/(rad/s))

Kaimal ((m/s)^2/(rad/s))

Wind and Wave Spectra

ScopeCode Comparisons for:

•Wave loading

•Support structures

•Geotechnical

•Coupled system dynamics

Goal1. 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 9 2006• Phase II (quadropod) complete by December 2006• Phase III (floating) complete by May 2007• 8 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