high reliability solutions & innovative concepts for offshore wind turbines
TRANSCRIPT
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63rd IEA Topical Expert Meeting
HIGH RELIABILITY SOLUTIONS AND INNOVATIVE
CONCEPTS FOR OFFSHORE WIND TURBINES
September 21-22 2010
SINTEF Energy Research, Trondheim, Norway
Organized by: CENER
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Disclaimer:
Please note that these proceedings may only be redistributed to persons in countries participating inthe IEA RD&D Task 11.
The reason is that the participating countries are paying for this work and are expecting that theresults of their efforts stay within this group of countries.
The documentation can be distributed to the following countries: Canada, Denmark, EuropeanCommission Finland Germany Ireland Italy Japan Korea Mexico the Netherlands Norway Spain
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International Energy Agency
Implement Agreement for Co-operation in the
Research, Development and Deployment of Wind
Turbine Systems: IEA Wind
The IEA international collaboration on energy technology and RD&D is organized under
the legal structure of Implementing Agreements, in which Governments, or their delegated
agents, participate as Contracting Parties and undertake Tasks identified in specific Annexes.
The IEAs Wind Implementing Agreement began in 1977, and is now called the
Implementing Agreement for Co-operation in the Research, Development, and Deployment of
Wind Energy Systems (IEA Wind). At present, 24 contracting parties from 20 countries, the
European Commission, and the European Wind Energy Association (EWEA) participate in
IEA Wind. Australia, Austria, Canada, Denmark, the European Commission, EWEA, Finland,
Germany, Greece, Ireland, Italy (two contracting parties), Japan, the Republic of Korea,
Mexico, the Netherlands, Norway (two contracting parties), Portugal, Spain, Sweden,
Switzerland, the United Kingdom, and the United States are now members.
The development and maturing of wind energy technology over the past 30 years has been
facilitated through vigorous national programs of research, development, demonstration, and
financial incentives. In this process, IEA Wind has played a role by providing a flexible
framework for cost-effective joint research projects and information exchange.
The mission of the IEA Wind Agreement continues to be to encourage and support thetechnological development and global deployment of wind energy technology. To do this, the
contracting parties exchange information on their continuing and planned activities and
participate in IEA Wind Tasks regarding cooperative research, development, and
demonstration of wind systems.
Task 11 of the IEA Wind Agreement Base Technology Information Exchange has the
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IEA Wind TASK 11: BASE TECHNOLOGY INFORMATION
EXCHANGE
The objective of this Task is to promote disseminating knowledge through cooperative
activities and information exchange on R&D topics of common interest. Four meetings on
different topics are arranged every year, gathering active researchers and experts. These
cooperative activities have been part of the Agreement since 1978.
Two Subtasks
The task includes two subtasks. The
objective of the first subtask is to develop
recommended practices for wind turbine
testing and evaluation by assembling an
Experts Group for each topic needing
recommended practices. For example, theExperts Group on wind speed
measurements published the document
titled Wind Speed Measurement and Use
of Cup Anemometry. A document dealing
with Sodar measurements are presently
Documentation
Since these activities were initiated in
1978, more than 60 volumes of
proceedings have been published. In the
series of Recommended Practices 11
documents were published and five of
these have revised editions.
All documents produced under Task 11
and published by the Operating Agent are
available to citizens of member countries
participating in this Task.
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COUNTRIES PRESENTLY PARTICIPATING IN THE TASK 11
COUNTRY INSTITUTION
Canada National Resources Canada
Denmark Ris National Laboratory - DTU
European Commission European Commission
Finland Technical Research Centre of Finland - VTT Energy
Germany Bundesministerium fr Unwelt , Naturschutz und Reaktorsicherheit -BMU
Ireland Sustainable Energy Ireland - SEI
Italy Ricerca sul Sistema Energetico - RSE S.p.A.
Japan National Institute of Advanced Industrial Science and Technology AIST
Republic of Korea POHANG University of Science and Technology - POSTECH
Mexico Instituto de Investigaciones Electricas - IEE
Netherlands SenterNovem
Norway The Norwegian Water Resources and Energy Directorate - NVE
SpainCentro de Investigaciones Energticas, Medioambientales y Tecnolgicas
CIEMAT
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CONTENTS
Page
INTRODUCTORY NOTE
a) BackgroundIX
b) Techniques..X
c) Topics to be addressedXI
d) Expected outcomes..XI
e) AgendaXII
PRESENTATIONS
1.Presentation of Introductory Note
Mr. John O. Tande SINTEF 01
1.Review of the OC3 IEA Wind Task 23 & Plans for OC4 under Task 30
Jason Jonkman, National Renewable Energy Laboratoy (NREL), USA..09
2.Findings and Prospects in Research on Support Structures and Foundations
in GIGAWIND alpha ventusJan Dubois, Leibniz Univ. of Hannover, Germany ...33
3. DeepCWind Floating Offshore Wind Project in the U.S.
Amy Robertson National Wind Technology Center (NREL) USA 49
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Anand Natarajan. Ris DTU. Denmark ...87
7. IDERMAR METEO: an innovative solution for offshore wind assesment.
Ral Guanche Garca. IH Cantabria. Spain 97
8. ZEFIR Test StationRajai Aghabi Rivas. IREC. Spain 111
9. The status of research and technology development on offshore wind energy in Japan
Chuichi Arakawa.Kyoto University, Japan................121
10. Research and Development of a Hybrid-spar for Floating Offshore Wind Turbine
Tomoaki Utsunomiya, Civil and Earth Resources Engineering Dep, Kyoto Univ. Japan ..133
11. Influence of Waves to Wind Misalignment to Dynamic Characteristics...."
Yoshida Shigeo. Fuji Heavy Industries. Japan 163
12. Integrated Dynamic Response Analysis of Spar-Type Wind Turbines with Catenary and
Taut Mooring.
Madjid Karimirad.Torgeir Moan. NTNU. Norway 169
13. Innovative Concepts for Offshore Wind Installations.
Peter Jamieson. Univ Stratchclyde UK .179
14. WindFlip, a transportation vessel for offshore floating wind turbines.
Torbjrn Mannsker. Marintek. Norway ..201
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European Commission .235
SUMMARY
a) Participants
b) Discussion
c) Future actions under the umbrella of IEA Wind
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INTRODUCTORY NOTE
Prepared by John Olav Tande
a) Background
Targets are set for a massive installation of offshore wind farms. In Europe alone plans suggest 40 GW
by 2020 and 150 GW by 2030 as viable. The development is ongoing, but in an early stage. Only about
2 GW of offshore wind farms have so far been installed, and all relatively close to shore at shallow
waters using what can be called on-shore wind technology. The exceptions are the Beatrice wind farm
installed at 46 m water depth using jacket sub-structures, the Alpha Ventus wind farm demonstratingjackets and tripods for foundation, and the floating wind turbine concepts, HyWind and BlueH. New
concepts are under development, e.g. SWAY, WindFloat and WindSea.
The experience so far indicates that technical challenges related to offshore installation, operation,
maintenance and repairs have been underestimated, though are now being addressed by the industry and
applied research.
Bottom-fixed wind farms, and mainly at shallow waters, are expected to dominate the near term
development, whereas industry-scale deployment of deep offshore (floating) wind farms are expected
after 2020.
A joint challenge in offshore wind is costs. The very ambitious targets for development of offshore wind
farms are only likely to be realized provided significant cost reductions. This can be achieved through
incremental improvements, e.g. gaining cost reductions through more efficient mass-fabrication and
installation procedures, reduction of risks and contingencies through experience and better engineering
tools, improved quality in critical parts and more cost-efficient operation and maintenance.
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b) Techniques
Improving the reliability of offshore wind turbines is paramount to the success of offshore wind
energy in the future. The larger the machine and further away from the coast, the larger the economic
loss for non-operation and associated maintenance. Vintage wind turbines often have the same gearbox
for their entire working lives. Modern wind turbines are much larger and optimised by weight and
efficiency. They need a number of major overhauls during their lifetimes to ensure efficient operation,
as does any conventional power generation plant. Wind turbines are currently designed in such a way
that the exchange of main components or sub assemblies is difficult. More efficient and newer drive
train concepts are needed to bring turbine reliability up to the required level. A more modular build up
of drive trains with more built in redundancy could help faster, cheaper and more efficient turbine
maintenance. The need for extremely reliable machines offshore can also be an extra driver for the
reliability of onshore machines.
Innovative concepts, such as variable speed, direct-drive offshore wind turbines are currently
emerging, with the aim of limiting the number of moving parts and lowering maintenance costs, as
gearboxes are expensive to replace offshore. A multi-pole gearless machine also operates at lower drive
train speeds and thus creates less stress on components. A main challenge for these concepts is to reduce
the weight on top of the tower, in order to optimise the use of material and limit the transport and
installation costs. So far, gearless machines have been heavier and more expensive to produce than their
geared equivalent. Lighter gearless technology is now being tested onshore.
Larger machines (5 to 10 MW), specifically designed for offshore could bring benefits in terms of
economies of scale by placing fewer larger machines on fewer foundations, or increasing the wind
farms power output. For example, economies of scale could also be realised by increasing the lifetime
to 30 years, provided it does not negatively affect the design.
Concepts such as two-bladed downwind turbines could emerge in the medium term. Two-bladed
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volumes required. Therefore the offshore wind industry must take urgent steps to rectify this situation.
In addition, the supply of substructures should not been seen as independent from their transport and
installation as an integrated approach is taken, taking into account unique site conditions and the
location of the wind farm.
Substructures represent a significant proportion of offshore development costs. In the case described
by Papalexandrou , the foundation represents 25% (5 MW turbine) to 34% (2 MW turbine) of
investment costs in 25m water depth. Thus, novel sub-structure designs and/or improved manufacturing
processes that reduce costs will be critical to improving the economics of offshore developments.
c) Topics to be addressed
The main objective is to hold a meeting to discuss and gather information on:
Wind Characteristics Measurement for Offshore Assessment
New Technological Solutions for WT
New Technical Solutions for Support Structures
The participants were encouraged to prepare presentations relevant to these objectives.
d) Expected outcomes
One of the goals of the meeting will be to gather the existing knowledge on the subject and come up
with suggestions / recommendations on how to proceed for future developments. The proceedings
document will contain:
Presentations by participants
Compilation of the most recent information on the topic
Main conclusions of the discussion session.
D fi iti f IEA Wi d RD&D f t l i thi t i
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e)Agenda
Tuesday, September 21st
09:00 Registration. Collection of presentations and final Agenda
09:25 Introduction by Host
President Sverre Aam, SINTEF Energy Research
09:40 Introduction by AIE Task 11 Operating Agent. Recognition of Participants
Mr.Felix Avia, Operating Agent Task 11 IEAWind R&D
10:00 Presentation of Introductory Note
Mr. John O. Tande SINTEF
10:30 Coffee Break
11:10 Review of the OC3 Project under IEA Wind Task 23 & Plans for OC4
under Task 30. Jason Jonkman, National Renewable Energy Laboratoy
(NREL), USA
11:35 Findings and Prospects in Research on Support Structures and
Foundations in GIGAWIND alpha ventus. Jan Dubois, Leibniz University of
Hannover, Germany
12:00 Lunch
13:00 DeepCWind Floating Offshore Wind Project in the U.S.
Amy Robertson. National Wind Technology Center, NREL, USA
13:25 SAEMar Project. Anchoring Systems for Renewable Marine Energies
Offshore Platforms. Ral Rodrguez Arias, Centro Tecnolgico de
Componentes, CTC, Santander .Spain
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15:05 Coffee Break
15:30 ZEFIR Test Station.Rajai Aghabi Rivas. IREC. Spain
15:55 The status of research and technology development on offshore wind energy
in Japan.Chuichi Arakawa,Kyoto University, Japan
16:20 Research and Development of a Hybrid-spar for Floating Offshore Wind
Turbine. Tomoaki Utsunomiya, Department of Civil and Earth Resources
Engineering Kyoto University, Japan
16:45 Influences of Wave to Wind Misalignment to Dynamic Characteristics and
Fatigue Loads on Spar-type Floating Offshore Wind Turbine.
Yoshida Shig, Fuji Heavy Industries. Japan
17:10 Adjourn
19.00 Informal dinner
Wednesday, September 22nd
09:00 Welcome
09:15 Integrated Dynamic Response Analysis of Spar-Type Wind Turbines with
Catenary and Taut Mooring.
Madjid Karimirad.Torgeir Moan. NTNU.Norway
09:40 Innovative Concepts for Offshore Wind Installations.
Peter Jamieson. Univ. Stratchclyde. UK
10:05 WindFlip, a transportation vessel for offshore floating wind turbines.
Torbjrn Mannsker. Marintek. Norway.
10:20 Research activities on bottom-supported wind turbines.
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11:40 EU-funded activities under FP7.
Thierry Langlois dEstaintot. New and Renewable Energy Sources. Directorate-
General Research. European Commission
12:05 Lunch
13:00 Discussion and Summary of Meeting
14:00 Technical Tour to the Ocean Basin Laboratory at MARINTEK.
16:00 End of the meeting
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PRESENTATIONS
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HIGH RELIABILITY SOLUTIONS
AND INNOVATIVE CONCEPTS
John Olav Giver Tande
Director NOWITECH
Introduction to IEA Wind TEM #63
Trondheim, 21-22 September 2010
1
Senior Research Scientist
SINTEF Energy Research
www.nowitech.no
NOWITECH in brief
Objective:Pre-competitive research laying a foundation for industrial value creationand cost-effective offshore wind farms. Emphasis on deep sea (+30 m).
R&D partners: SINTEF, IFE, NTNU + associates: Ris DTU (DK), NREL & MIT(US), Fraunhofer IWES (DE), Universit y of Strathclyde (UK), TU Delft (NL)
Industry partners: Statkraft, Statoil, Vestavind Kraft, Dong Energy, Lyse,Statnett, Aker Solut ions , SmartMotor , NTE, DNV, Vestas, Fugro Oceanor,Devold AMT, TrnderEnergi, EDF + associates: Innovation Norway, Enova,NORWEA, NVE, Energy Norway, Navitas Network
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NOWITECH vision large scale deployment of deep sea offshore wind turbines
an internationally leading research communit y on offshore windtechnology enabling industry partners to be in the forefront.
Means and main ambitions
Combine wind technology know-how with offshore and energy industryexperience to enhance development of o ffshore w ind.
Establish a recruitment and educational programme that provides fo rhighly qualified staff at Master and PhD level for serving the industry.
Build strong relations wi th selected top international research partners.
Facilitate active involvement by industry partners to ensure relevanceand efficient communication and utilization of results.
3
Support to industry is through pre-competitive research commercialdevelopment w ill come as a result and be run in separate projects.
Act ively pursue opportuni ties to increase R&D act ivi ty on crit ical issues.
Strong motivation for of fshore wind R&D
Huge potential
Offshore wind is vital forbattling climate change,
KarmyKarmyKarmy
Offshore 2030: 150 GW*
Offshore 2020: 40 GW* HyWind(floating, 200m)
(jacket, 46m)
security of supply
Development at an early
stage; less than 2% of the
l b l i d it i
Offshore 2009: ~2 GW
TEM 63 "High Reliability Solutions and Innovative Concepts for Offshore Wind Turbines"
TEM 63 "Hi h R li bilit S l ti d I ti C t f Off h Wi d T bi "
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Lots of options to improve bottom-fixed support structures
Mono-pile dominates themarket for shallow waters
Jackets and tripods are-
depths (+30 m)
Various new concepts arebeing developed byindustry, incl. concrete sub-structures (Vici Ventus)
Lots of room forimprovements throughintegrated design, incl.control actions to reduce
5
Design should also consideralternative ways for
installation.
Graphics: copy from Haiyan Long , PhD student NTNU, 2009
Many exciting floating concepts
(2009, 2,3 MW)
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The HyWind demo in operation since Sept. 2009
Turbine power 2,3 MW
Turbine weight 138 tons
Nacelle height 65 m
Rotor diameter 82,4 m
Water depth 150700 m
Displacement 5300 tons
Moorin 3 lines
7
D @ water line 6 m
D submerged 8,3 m
Data from Statoil
One big advantage of floaters: relatively easy installation!
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Is HyWind stable? Yes; according to
Simulations and Test in Ocean Basin Lab (2005)
20
)
-5
0
5
10
wertopdisplacemen
t(
9
100 150 200 250 300
-15
-
Time (s)
To With stabilizer
Without stabilizer
2.5
3
changle[-] controller tuned
controller not tuned
Measurements of HyWind operating at 2,3 MW
1
1.5
2
eantowerpit
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Will floaters be economic?
Wind
turbine
O&MWind
turbine
O&M
Sub-structure
Grid
Sub-structure
Grid
HyWind 2,3 MW floater: 1300 tons of s teel;simple struc ture, suitable for mass
production; quick installation; amounts of
steel can be reduced through
optimization
11
p a entus ac et: tons o
steel; complex structure & installation;
what wi ll the steel weight be at 50 m waterdepth?
Tower top weight is cr itical for keeping the cost down
TEM 63 High Reliability Solutions and Innovative Concepts for Offshore Wind Turbines
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An optimized grid is a key for eff icient in tegration
Hydropower
withstora e
Statnett vision (2009)Main challenges
Many possible grid configurations
New market solutions are required
New technology (HVDC VSC, mult i-
SK
1,2,3
NorNed
SK 4
NORD.LINK / NorGer
Ekofisk
Wind farms
i
terminal, hybrid HVDC/HVAC, .. )
Cost, Reliability and Security of Supply
1080
10100
10120
10140
leconfigurations
13
Wind and hydro:
a win-win combination
0 5 10 15 20 25 3010
0
1020
1040
10
Number of nodes
Numb
erofcab
Why bother with all th is new, when there are
plenty of challenges in need for urgent attention?
Need for both; long term R&Dare the answer to be prepared
for the ur encies of tomorrow
New solutions should be robust
Systems for remote monitoring,
state estimation and control
g y p
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NOWERI: a platform for R&D (expected 2012)
~225 kW
15
Rounding up
Remarkable results are already achieved by industry and
R&D institutes on offshore wind
Technology still in an early phase Big potential provided
The goal of this meeting is to address high reliability
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Review of the OC3 ProjectUnder IEA Wind Task 23
& Plans for OC4 Under Task 30IEA Wind Task 11 TEM #63
September 21-22, 2010
Trondheim, Norway
Jason Jonkman, Ph.D.Senior Engineer, NREL
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
The Offshore Code Comparison Collaboration (OC3)
project operated under Subtask 2 of IEA Wind Task23
The OC3 & OC4 Projects
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IEA Wind Task 11 TEM #63 3 National Renewable Energy Laboratory
OWTs are designed using aero-hydro-servo-elastic codes
The codes must be verified to assess their accuracy
OC3/OC4 Background
Discuss modeling strategies
Develop suite of benchmark models & simulations
Run simulations & process results
Compare & discuss resultsActivities
OC3/OC4 Activities & Objectives
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IEA Wind Task 11 TEM #63 5 National Renewable Energy Laboratory
OC3 Participants & Codes
3Dfloat
ADAMS-AeroDyn-HydroDyn
ADAMS-AeroDyn-WaveLoads
ADCoS-Offshore
ADCoS-Offshore-ASAS
ANSYS-WaveLoads BHawC
Bladed
Bladed Multibody
DeepC
FAST-AeroDyn-HydroDyn
FAST-AeroDyn-NASTRAN
FLEX5
FLEX5-Poseidon
HAWC HAWC2
SESAM
SIMPACK-AeroDyn
Simo
All inputs are predefined:
NREL 5-MW wind turbine, including control system Variety of support structures
Wind & wave datasets
A stepwise procedure is applied:
Load cases selected to test different model featuresApproac
h
OC3/OC4 Approach & Phases
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IEA Wind Task 11 TEM #63 7 National Renewable Energy Laboratory
Load Cases
1.X Full-System Eigenanalysis
Full-system flexibility
Elastic response only
Compared natural frequencies &
damping ratios2.X Rigid
Rigid turbine
Aerodynamics without hydro:
Steady & turbulent winds
Hydrodynamics without aero:
Regular & irregular waves
3.X Onshore Wind Turbine
Flexible tower, drivetrain, & rotor
Rigid substructure
Aero-servo-elastics without hydro:
Steady & turbulent winds
4.X Inverted Pendulum
Flexible support structure
Rigid tower top
Hydro-elastics without aero:
Regular & irregular waves
5.X Full-System Dynamics
Full-system flexibility
Full aero-hydro-servo-elastics:
Steady winds with regular waves
Turbulent winds with irregular waves
Output Parameters
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IEA Wind Task 11 TEM #63 9 National Renewable Energy Laboratory
OC3 Results
1 conference paper per phasepublished/presented:
Phase I: Torque, 2007
Phase II: EOW, 2007
Phase III: AIAA, 2009
Phase IV: EWEC, 2010
Final report reviewing allphases in publication,including updated results
submitted since originallypublished
Journal article in progress
Jump in complexity from monopile to
tripod: Multiple members
Statically indeterminate (loads influencedby relative deflection of members)
Nonaxisymmetric
OC3 Phase III Results: Tripod
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IEA Wind Task 11 TEM #63 11 National Renewable Energy Laboratory
Jump in complexity from fixed to floating:
Low-frequency modes (influence onaerodynamic damping & stability)
Large platform motions (coupling with turbine)
Complicated shapes (radiation & diffraction) Moorings (new component)
Key findings (may only apply to thisspar):
Radiation damping is negligible; so, codes thatapply Morisons equation are adequate
Quasi-static mooring models provide adequatereactions for global response analysis;dynamic mooring models, however, result inmore line excitation at higher frequencies
Turbine structural flexibilities had an effect onturbine loads, but little effect on spar motions
Spar Concept bySIWAY
OC3 Phase IV Results: Spar Buoy
OC3-Hywind Spar Buoy
Title: Verification of simulation codes for ajacket-supported fixed-bottom WT
Coordinator: Fraunhofer-IWES
Rambll has kindly agreed to make theUpWind WP4 reference jacket available to
OC4 Phase I Plans: Jacket
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IEA Wind Task 11 TEM #63 13 National Renewable Energy Laboratory
Title: Verification of simulation codes fora WT on a floating semi-submersible
Coordinator: NREL
OC4 participants will choose betweenPrinciple Power Inc.s (PPI) WindFloat &DeepCwind generic semi-submersibles:
PPI WindFloat is a patented commercialsystem with first full-scale installationscheduled for late 2011
DeepCwind is a generic publically availabledesign to be wave-tank tested at 1/50th scale
in early 2011
Code-to-code comparison results will bepublished in a conference paper in 2012
Spar Concept by SWAY
OC4 Phase II Plans: Semi-submersible
WindFloat(Image: D. Roddier, PPI)
OC4 focuses on code-to-code verification;
code-to-experiment validation also needed OC4 participants dont comprise all experts
needed to develop field validation plan
Separate meeting proposed for 2011
OC4 Code Validation Experts Meeting
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IEA Wind Task 11 TEM #63 15 National Renewable Energy Laboratory
OC3/OC4 aims to verify OWT dynamics
codes
Benchmark models & simulations established
Simulations test a variety of OWT types &model features
Code-to-code comparisons have agreed well
Differences caused by variations in:
Model fidelity
Aero-, hydro-, & structural-dynamic theories
Model discretization
Numerical problems
User error
Many code errors have been resolved
Engineers equipped with modeling experience
Spar Concept by SWAYSemi-submersibleConcept
Summary
Thank You for Your Attention
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IEA Wind Task 11 TEM #63 17 National Renewable Energy Laboratory
IEA Task 23 Organizational Structure
OC3 Coordination & Meetings
E-mail coordination
Net-meetings held every 1-2months
Physical meetings held 1-2
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IEA Wind Task 11 TEM #63 19 National Renewable Energy Laboratory
Countries will pay 5,000/year to participate
9 countries assumed to join, for an annual budget of 45000/yr
No limit on the number of participants, but each participant
should be approved by the countrys ExCo representative Meeting hosts will donate costs voluntarily
Spar Concept by SWAY
OC4 Funding & Cost
Operating Agent Responsibilities Funding (3 yr)
NREL WP2 CoordinationExpert Meeting Coord.
ReportingProject Management
Website
95000
Fraunhofer-IWES WP1 CoordinationReporting
40000
TOTAL 135000
OC4 Project Schedule
ID Tas k Na me
1 ExCo Approval of Annex 302 Receive Commitment Letters3 Receive Funds4 Jacket Code Comparison - Work Package 15 Publish Paper or Report on Jacket6 Establish Floating Design Concept7 Floating Platform - Work Pakage 2
11/9
2/1
3/31
1/29
O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O
2010 2011 2012 2013
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IEA Wind Task 11 TEM #63 21 National Renewable Energy Laboratory
OC4 Organizational Structure
Interested countries must joinTask 30
Committed:
Germany, USA
Declined:
EC, EWEA, Switzerland
Country Commitments
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Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by Midwest Research Institute Battelle
OC3: Benchmark Exercise of
Aero-elastic Offshore WindTurbine Codes
J A Nichols and T R Camp, Garrad Hassan and Partners Ltd.
J Jonkman and S Butterfield, NRELT Larsen and Anders Hansen, Ris
J Azcona, A Martinez and X Munduate, CENERF Vorpahl and S Kleinhansl, CWMT
M Kohlmeier, T Kossel and C Bker, Leibniz University of HannoverD Kaufer, SWE University of Stuttgart
Phase III: Offshore Tripod
Significant jump incomplexity frommonopile substructure.
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IEA Wind Task 11 TEM #63 25 National Renewable Energy Laboratory
Modelling wave loads
Importance of modelling the structure near thesea surface in detail
Without a fine discretisation, sharp jumps areseen in load signals
-4000.0000
-3500.0000
-3000.0000
-2500.0000
-2000.0000
-1500.0000
-1000.0000
-500.0000
0.0000
0 5 10 15 20 25 30 35
Time [s]
ShearForce[kNm]
Upwind leg axial shearforce (coarsediscretisation)
Upwind leg axial shearforce (fine
discretisation)
A
xialForce
(kN)
Modelling overlapping members
It is important to takeaccount of theoverlapping regionswhen structuremembers join at nodes
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IEA Wind Task 11 TEM #63 27 National Renewable Energy Laboratory
Modelling shear deflection
Bernoulli-Euler theoryonly considers purebending of a beam.
One side is compressedwhile the other isstretched.
In real beams, there issome shear deformationof the material.
This becomes importantonce relative deflection ofjoined members becomes
xM
P( )MPl
EI
lx 6)4(
12
2
++=
l
212lGA
EI
S
=
Modelling shear deflection
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IEA Wind Task 11 TEM #63 29 National Renewable Energy Laboratory
Results - Eigenanalysis
0.0000
0.5000
1.0000
1.5000
2.0000
2.5000
3.0000
1stT
owerFore-Aft
1stT
owerSide
-to-Side
1stD
rivetrain
Torsion
1stBlad
eCollectiveFlap
1stBlad
eAsymmetric
Flap
wise
Pitch
1stBlad
eAsymmetric
Flap
wise
Yaw
1stBlad
eAsymmetric
Edgewise
Pitch
1stBlad
eAsymmetric
Edgewise
Yaw
2ndTowerF
ore-Aft
2ndTowerSide
-to-Side
2ndBladeCollective
Flap
2ndBladeAsymmetric
Flap
wise
Pitch
2ndBladeAsymmetric
Flap
wise
Yaw
CENER FASTNASTRAN Natural Frequency (Hz)
CENER Bladed Natural Frequency (Hz)
CWMT ADCoS Natural Frequency (Hz)
GH Bladed Natural Frequency (Hz)
GH Bladed (Timoshenko) Natural Frequency (Hz)
LUH WaveLoadsANSYS Natural Frequency (Hz)
Risoe HAWC2 Natural Frequency (Hz)
Risoe HAWC2_BE Natural Frequency (Hz)
SWE FLEX5Poseidon Natural Frequency (Hz)
Results Output Locations
1
2
3
4
5
6
1
2
3
4
5
6
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IEA Wind Task 11 TEM #63 31 National Renewable Energy Laboratory
Results bending moments due to wave loads
-15000
-10000
-5000
0
5000
10000
5 10 15
Simulation Time (s)
BendingMoment(kNm
-700
-600
-500
-400
-300
-200
-100
0
5 10 15
Simulation Time (s )
BendingMoment(kNm)
-10000
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
5 10 15
Simulation Time (s)
BendingMoment(kNm)
-3000
-2500
-2000
-1500
-1000
-500
0
5 10 15
Simulation Time (s)
BendingMoment(kNm
-1500
-1450
-1400
-1350
-1300
-1250
-1200
5 10 15
Simulation Time (s)
BendingMoment(kNm)
-1800
-1600
-1400
-1200
-1000
-800
-600
-400
-200
0
5 10 15
Simulation Time (s)
BendingMoment(kNm)
1 2
3 4
5 6
-15000
-10000
-5000
0
5000
10000
5 10 15
Simulation Time (s)
BendingMoment(kNm
-700
-600
-500
-400
-300
-200
-100
0
5 10 15
Simulation Time (s )
BendingMoment(kNm)
-10000
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
5 10 15
Simulation Time (s)
BendingMoment(kNm)
-3000
-2500
-2000
-1500
-1000
-500
0
5 10 15
Simulation Time (s)
BendingMoment(kNm
-1500
-1450
-1400
-1350
-1300
-1250
-1200
5 10 15
Simulation Time (s)
BendingMoment(kNm)
-1800
-1600
-1400
-1200
-1000
-800
-600
-400
-200
0
5 10 15
Simulation Time (s)
BendingMoment(kNm)
1 2
3 4
5 6
Results shear forces due to wave loads
-100
-50
0
50
100
150
5 10 15
Simulation Time (s)
ShearForc
e(kN)
-200
-150
-100
-50
050
100
150
200
250
300
5 10 15
Simulation Time (s)
ShearForc
e(kN)
40
60
80
100
ce(kN)
20
30
40
50
ce(kN)
1 2
3 4
-100
-50
0
50
100
150
5 10 15
Simulation Time (s)
ShearForc
e(kN)
-200
-150
-100
-50
050
100
150
200
250
300
5 10 15
Simulation Time (s)
ShearForc
e(kN)
40
60
80
100
ce(kN)
20
30
40
50
ce(kN)
1 2
3 4
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IEA Wind Task 11 TEM #63 33 National Renewable Energy Laboratory
Results axial forces due to wave loads
-7103
-7102
-7102
-7101
-7101
-7100
-7100
-7099
-7099
5 10 15
Simulation Time (s)
AxialForce(kN)
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
5 10 15
Simulation Time (s)
A
xialForce(kN
-1200
-1000
-800
-600
-400
-200
0
200
400
600
5 10 15
Simulation Time (s)
A
xialForce(kN
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
5 10 15
Simulation Time (s)
AxialForce(kN
-6000
-5000
-4000
-3000
-2000
-1000
0
5 10 15
Simulation Time (s)
AxialForce(kN
-7250
-7240
-7230
-7220
-7210
-7200
-7190
-7180
-7170
-7160
5 10 15
Simulation Time (s)
AxialForce(kN)
1 2
3 4
5
6
-7103
-7102
-7102
-7101
-7101
-7100
-7100
-7099
-7099
5 10 15
Simulation Time (s)
AxialForce(kN)
-4500
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
5 10 15
Simulation Time (s)
A
xialForce(kN
-1200
-1000
-800
-600
-400
-200
0
200
400
600
5 10 15
Simulation Time (s)
A
xialForce(kN
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
5 10 15
Simulation Time (s)
AxialForce(kN
-6000
-5000
-4000
-3000
-2000
-1000
0
5 10 15
Simulation Time (s)
AxialForce(kN
-7250
-7240
-7230
-7220
-7210
-7200
-7190
-7180
-7170
-7160
5 10 15
Simulation Time (s)
AxialForce(kN)
1 2
3 4
5
6
Motion of the dynamic support structure
-0.035
-0.030
-0.025
-0.020
-0.015
-0.010
-0.005
0.000
0.005
0.010
5 10 15
Tower
Top
Displacement
(m
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Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by Midwest Research Institute Battelle
IEA Wind Task 23 OC3:Phase IV Results Regarding Floating Wind Turbine Modeling
Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by the Alliance for Sustainable Energy, LLC
Floating Challenges & Phase IV Model
Low frequency modes:
Influence aerodynamic damping & stability
Large platform motions:
Coupling with turbine
Complicated shape:
Radiation & diffractionChallenge
s
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IEA Wind Task 11 TEM #63 37 National Renewable Energy Laboratory
Aero-Hydro-Servo-Elastic Capabilities
FAST Bladed ADAMS HAWC2 3Dfloat Simo SESAM / DeepC
Code Developer
NREL GH MSC + NREL
+ LUH
Ris-DTU IFE-UMB MARINTEK DNV
OC3 Participant
NREL + POSTECH GH NREL + LUH Ris-DTU IFE-UMB MARINTEK Acciona + NTNU
Aerodynamics
( BEM or GDW )
+ DS
( BEM or GDW )
+ DS
( BEM or GDW )
+ DS
( BEM or GDW )
+ DS
( BEM or GDW ) BEM None
Hydrodynamics
Airy++ ME,
Airy + PF + ME
( Airy+or Stream )
+ ME
Airy++ ME,
Airy + PF + ME
Airy + ME Airy + ME Airy + PF + ME Airy++ ME,
Airy + PF + ME
Control System (Servo)
DLL, UD, SM DLL DLL, UD DLL, UD, SM UD DLL None
Structural Dynamics (Elastic)
Turbine: FEMP+( Modal / MBS ),
Moorings: QSCE
Turbine: FEMP+( Modal / MBS ),
Moorings: UDFD
Turbine: MBS,Moorings: QSCE,
UDFD
Turbine: MBS / FEM,Moorings: UDFD
Turbine: FEM,Moorings: FEM, UDFD
Turbine: MBS,Moorings: QSCE,
MBS
Turbine: MBS,Moorings: QSCE,
FEM
Airy+ Airy wave theory+) with free surface corrections
BEM blade-element / momentum
DLL external dynamic link library
DNV Det Norsk Veritas
DS dynamic stall
GDW generalized dynamic wakeFEM
P finite-element method
P) for mode preprocessing only
MBS multibody-dy namics formulation
ME Morisons equation
MSC MSC Software Corporation
PF l inear potential flow with radiation &diffraction
QSCE quasi-st atic catenary equations
SM interface to Simulinkwith MATLAB
UD implementat ion through user-defined
subroutine available
UDFD implementat ion through user-defined force-
displacement relationships
Phase IV Load Cases
LoadCase
Enabled DOFs Wind Conditions Wave Conditions Analysis Type
1.2 Platform, tower,drivetrain, blades
None: air density = 0 Still water Eigenanalysis
1.3 Platform, tower,drivetrain, blades
None: air density = 0 Still water Static equilibrium solution
1.4 Platform None: air density = 0 Still Water Free-decay test time series
4.1 Platform, tower None: air density = 0 Regular Airy: H= 6 m, T= 10 s Periodic time-series solution
4 2 Platform tower None: air density = 0 Irregular Airy: Hs = 6 m Tp = 10 s Time-series statistics DELs
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IEA Wind Task 11 TEM #63 39 National Renewable Energy Laboratory
Output Parameters (57 Total)
Rotor BladeLoads & Deflections
13 Outputs
Drivetrain & GeneratorLoads & Operation
7 Outputs
TowerLoads & Deflections
15 Outputs
EnvironmentWind & Waves4 Outputs
PlatformDisplacements6 Outputs
Mooring SystemFairlead & Anchor
Tensions & Angles12 Outputs
Output Parameters & Results Legend
Results Legend
Full-System Eigenanalysis
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IEA Wind Task 11 TEM #63 41 National Renewable Energy Laboratory
Free Decay
Free Decay in Platform Surge
Free Decay in Platform Pitch
Hydro-Elastic Responsewith Regular Waves
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IEA Wind Task 11 TEM #63 43 National Renewable Energy Laboratory
Hydro-Elastic Responsewith Irregular Waves
Aero-Hydro-Servo-Elastic Responsewith Regular Waves
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IEA Wind Task 11 TEM #63 45 National Renewable Energy Laboratory
Aero-Hydro-Servo-Elastic Responsewith Irregular Waves
Aero-Hydro-Servo-ElasticEffective RAOs
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IEA Wind Task 11 TEM #63 47 National Renewable Energy Laboratory
Close agreement was not achieved by all codes:
What was the reason?
The effective RAO load case was somewhat academic:
What response charateristic is more relevant? Alternative suggested by IF RAOs could be derived from irregular
time series & cross spectra between excitation & response
The stochastic response statistics & spectra are sensitive to
simulation length:
What length would be more appropriate?
How can we eliminate start-up transients from the comparisons?
Unresolved Issues of OC3 Phase IV
OC3-Hywind platform was considered as a rigid body; nohydro-elastic effects
OC3-Hywind platform is simple in shape; only a single member
Hydrodynamic radiation & diffraction was negligible in theOC3-Hywind spar buoy
Sea current was never considered
Limitations of OC3 Phase IV
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FindingsFindings andand ProspectsProspects
in Research on Supportin Research on Support StructuresStructures andand
FoundationsFoundations in GIGAWINDin GIGAWIND alphaalphaventusventus
Raimund Rolfes1, P. Schaumann1, Jan Dubois1,T. Schlurmann1, L. Lohaus1, M. Achmus1, H. Huhn2
1) Leibniz Universitt Hannover2) Fraunhofer IWES
1. The alpha ventus Wind Farm
2. The GIGAWIND alpha ventus
Research Project within RAVE
3. Research Objectives
4. GIGAWIND alpha ventusin DetailWP1 - Load Modelling for WavesWP2 - Fatigue Resistance /
Nov 2009
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1st German offshore wind farm
12 x 5MW OWECs (Multibrid / REpower) Operator: DOTI
Distance from coast: 45 km
Water depth: 30m
Planning: since 2006
Installation: 2008 2009
Research: RAVE
alpha ventus
2nd installationphase 2009
About alpha ventus
Location
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Layout of alpha ventus
Multibrid M5000
REpower 5M
Met MastFINO 1
GIGAWIND project GIGAWIND project
Holistic design concept for offshore windturbine support structures
BMU project (Coordination: LUH)3 Mio.
member in
50 Mio.
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GIGAWIND alpha ventusConsortium
Franzius-Institutfr Wasserbau und
Ksteningenieurwesen
Cooperation Partners:
coordination
deputy coordination
associated project in: funded by:
Cost reduction of OWEC support
structures
lighter support structures
optimised design process
Comprehensive simulation and design
package
holistic design concept
Research Objectives
corrosionrate
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WP1 - Load Modelling for Waves
Large scale model tests
Impact loads of breaking waves
Waveloads of nonbreaking waves
Spatial and time-resolved pressuredistribution
Wave kinematics Validation
Computational fluid dynamics (CFD)
Calibration of numerical models
Analysis of impact loads
Probabilistic design concepts
Influence of sea state parameters
Source: Franzius-Institute for Hydraulic, Waterways and Coastal Engineering, Arndt Hildebrandt, 2010
Wave Loads
Large scale model tests:
Impact loads of breaking waves
Waveloads of nonbreaking waves Spatial and time-resolved pressure
distribution
Wave kinematics
Validation
Wave Loads
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fixture and box
pile
sleeve
testedinlaboratory
anima
tionoffshore
box
Measurements on Grouted Jointsof real structures
Hybrid connections for Offshore-WEC Grouted Joints
WP 2 - Fatigue Resistance /Manufacturing Aspects
Source: Nick Lindschulte, Institute of Building Materials Science, 2010
18m
sea level
tripod
relative displacementbetween pile and sleeve
z
r
t
measuring box
standard inductivesensor
Measurement of manufactured
geometry
Implementation of filters
FE-analyses of imperfect structure
Assessment of fatigue resistance of
imperfect tubular welded joints
Influence of Manufacturing Aspects on Fatigue Assessment
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Transfer of electrochemical laboratory methodsonto offshore structures
Example: EP-coating on thin sheet for tin cans in 3% acetic acid
laboratory cell
proper coating weak coating
10-2
10-1
100
101
102
103
104
103
104
105
106
107
108
109
1010
1011
Impedance/Z/
/
c
m2
10-2
10-1
100
101
102
103
104
103
104
105
106
107
108
109
1010
1011
Impedance/Z/
/
c
m2
t = 0
t = 4d
t = 8d
t = 11d
t = 0
t = 4d
t = 8d
t = 11d
defect after 46 days
Corrosion Monitoring
WP3 - Corrosion Protection
Source: Fraunhofer IWES, Holger Huhn
Implementation and testing of sensor electrodes oncoated samples
2 weeks
6 months
Corrosion Monitoring
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Field exposure test of sensorized and coated samples
WP3 - Corrosion Protection
Corrosion Monitoring
Source: Fraunhofer IWES, Holger Huhn
High Performance Mortar for Corrosion Protection
By polymer modification of the HPM:
The freeze-thaw resistance can beincreased compared to a concrete for
Hydraulic Structures The spalling of the surface decreases
to a minimum (153 g/m)
Spalling of the concrete surfaces after several freeze-thaw-cycles
0
250
500
750
1000
1250
1500
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
freeze-thaw-cycles
spalling[g/m]
reference
styrene-butadiene10,0%
styrene-butadiene20,0%
styrene-acrylate10,0%
styrene-acrylate20,0%
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Example Reduction of stiffness in the upper sectionof the mast by dissolving 264 bolts: ~100%
Method Multi-parameter eigenvalue problem,scanning parameter
Detection Parameter of intact/defect system: 0,999 => 0,004
means reduction of stiffness of 99,6%.
Inverse load detection from measured structural responses
Early damage detection
Damage localisation (global, local)
Damage quantification
Damage curve over life time percomponent
Estimation of residual load capacityand residual life time
Serial, cost-efficient offshore application
Test of the monitoring system atan onshore-WT with girder mast
Sdwind S70 1,5MW
SHM
REpower5
M(
av)
WP4 - Load Monitoring Systems
Monitoring of an Offshore Support Structure (SHM):(foundation, tower and rotor blades)
Source: Institute of Structural Analysis, Johannes Reetz
TP5:Arne Stahlmann
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WP5 - Scour Protection /Scour Monitoring
Research Activities on Scouring Phenomena
0, 3000
RW: d=2.5m, Hm=0.76m, Tm=5.48s
S/D1P: 0.823P: 1.13MC: 1.11 3P
1P
MC
Physical model tests (1:40 & 1:12)
Modeling of scours
Flow pattern and turbulences
Scouring processes at complex offshore
structures
Scour protection systems Calibration and validation of numerical
models
Computational fluid dynamics (CFD):
Simulation of scour depths and evolutions
Forecasting and dimensioning
Soil-structure interaction
Franzius-Institute (2010)
Franzius-Institute (2010)
Innovative Scour Protection Chains
Connected chains of concrete elements;
physical model tests (1:40 & 1:12)
Soil-Structure Interaction (FEM)
Investigations on the effect of scours on
the stiffness distribution, deflection lines
and secant rotations (right figure)
Scour Protection & Soil-Structure Interaction
Monopile: S: scour depth
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Foundation system and loading
condition of monopile foundation
a) pile deflection lines
after N cycles
b) Accumulation rate of horizonatal
displacement at pile topStress distributions from the numerical analyses
WP6 - Soil Modelling
Source: Institute of Soil Mechanics and Foundation Engineering, Khalid Abdel-Rahman, Marina Mller
Investigation based on Cyclic triaxial test results FE simulations
Result: Performance of a monopile
under cyclic loads
Stiffness Degradation Method (SDM):Estimation of Monopile Deformationunder Cyclic Lateral Load
Validation of the Stiffness DegradationMethod (SDM)
SDM Characteristics:
Allows estimating the accumulatedpile deformation under cyclichorizontal loading
Combination of cyclic triaxial testresults and numerical simulations
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WP6 - Soil Modelling
Prediction of the Axial Pile Capacity
Predicting the shaft friction with CPT-based methods
Validated against a database
Just 6 pile tests are relevant for German Conditions
Pile diameter is almost less than 1.0 m
Over proportional arise of pile capacitywith increasing diameter
WP6 - Soil Modelling
Source:InstituteofSoilMechanicsandFoundationEngineering,
Khalid
Abdel-Rahman,
MarinaMller
General structural modelinitial state based on construction data
Measurement datadynamic behaviour from system
identification (AR models)
Definition of validation
parameter
on the basis of sensitivity analysis
Validation process- optimisation algorithm, e. g. Newton iteration,
inverse eigenvalue problem (Natke)
GUI of the software Vali tooleigenfrequencies as
target values
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WP8
FAST
ADAMS
Aerodynamic
loads
Aerodynamic
loads
Date Base Controller GUI / Visualization
AeroDyn
PoseidonWaveLoads ANSYS
Design- and Simulation Framework for Offshore Wind Turbines (DeSiO)
GIGAWIND alpha ventus -Tools
Poseidon/WaveLoadsAV4 alpha ventusAdams/WaveLoads/ AeroDynOC3 Tripod
WaveLoads OC3 Tripod
DeSiO OC3 Tripod
WP8 - Holistic Design Concept
Source: Institute for Steel Construction, Vsquez; Institute of Structural Analysis, Reil, Kohlmeier, 2010
Modelling
AeroDyn
WaveLoadsADAMS
FAST
DeSiO
Poseidon ANSYS
GIGAWIND alpha ventus - Tools
ControllerDate base Visualization
FALCOS
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Multibody Dynamics Simulation
AeroDyn
WaveLoadsADAMS
FAST
DeSiO
Poseidon ANSYS
GIGAWIND alpha ventus - Tools
ControllerDate base Visualization
FALCOS
OC3 floating turbine
analysed in Adams
OC4 jacket structure
analysed in Adams
5MW NREL Baseline Turbinegenerated with FAST
Wave loading on floating
spar-buoy structuregenerated by WaveLoads
WP8 - Holistic Design Concept
Source: Institute for Steel Construction, Vsquez; Institute of Structural Analysis, Reil, Kohlmeier, 2010
OC4 jacketstructure
analysed inWaveLoads
FE-Modelling of Structural JointsFatigue assessments according to the
structural stress concept
Y-, Double-K, Tripod-Joint, and others
AeroDyn
WaveLoadsADAMS
FAST
DeSiO
Poseidon ANSYS
GIGAWIND alpha ventus - Tools
ControllerDate base Visualization
FALCOS
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Conclusion
Methods for several aspects of the
design process for OWEC support
structures has been developed
Holistic design concept with an easyoperable design and simulation package
Validation of simulation models against
measurement data from the offshore test
field alpha ventus
Offshore test field alpha ventusin November 2009
OWEC support structures have to become
an cost efficient mass product!
Cost optimisation of support structuresdesigned for further offshore wind farms
Thank you for yourThank you for your
attention!attention!
www.gigawind.de
www.rave-offshore.de
www.alpha-ventus.de
This presentation is composed bycontributions from researchers ofGIGAWIND alpha ventus:
WP 1 Arndt HildebrandtWP 2 Nick Lindschulte
Malte GottschalkWP 3 Holger Huhn
Hannes WeickenWP 4 Johannes Reetz
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NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
DeepCWind Floating Offshore WindProject in the U.S.
Topical Expert Meeting#63
Amy Robertson
September 21, 2010
DeepCWind Project Maine, USA
New Technology Development
Initiative for floating windtechnology
Funding ~ $25M US Dollars
1/50th scale model testing
D
(>60 )
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NATIONAL RENEWABLE ENERGY LABORATORY
UMaine Test Site Timeline
This is a pilot project to evaluate feasibility and cost ofdeploying floating offshore wind turbines.
The primary objectives are to:
Validate coupled aeroelastic/hydrodynamic models for floatingoffshore wind turbines.
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NATIONAL RENEWABLE ENERGY LABORATORY
STEP 1: Scaled Model Testing
5
1/50th scale models willbe tested at a world classwave/wind facility
Models are based onNREL 5MW referenceturbine.
Model testing isscheduled for April 2011.
Generic Floating Platforms
Three generic platformdesigns have beenidentified for tanktesting.
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NATIONAL RENEWABLE ENERGY LABORATORY
Validate/revise coupled aeroelastic/hydrodynamic models
7
Development ofnumerical models ofall three generic
designs. Data generatedfrom these tests willbe used to validateNRELs coupledaeroelastic/hydrodynamic
models.
Model Scaling
Offshore platforms are typically scaledusing Froude Number and geometricsimilarity:
Frm= Frf m= model
Lm= Lf f = full scale
Froude Number will not scale all parametersproperly, but maintains proper inertia scaling
Fr =C
2
gL
Froude Number:ratio of bodysinertia to
gravitational forces
C= wave celerity
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NATIONAL RENEWABLE ENERGY LABORATORY
Summary of Scale Factors
9
0.5
A 2 2
3 3
3
C 1 0.5
0.5
1 0.5
2 3
23 7/2
12
12
1 0.5
D
1.
2. C/
3. () ?
Reference Full-Scale Spar Platform
C3 =50 =60 =75
B ( ) A ( ) 10
= / 0.200 0.167 0.133
( B ) A ( ) 87. 6 = / 1.752 1.460 1.168
() 249718
= /
31.998 1.156 0.592
() 77.6
= / 1.552 1.293 1.035
D () 3.78
= / 0.076 0.063 0.050
B D () 6.5
= / 0.130 0.108 0.087
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NATIONAL RENEWABLE ENERGY LABORATORY
FAST with AeroDyn and HydroDyn
11
Structural-dynamic model for horizontal-axis turbines:
Coupled to AeroDyn, HydroDyn, and controller for aero-hydro-servo-elastic simulation
Evaluated by Germanischer Lloyd WindEnergie
Turbine Configurations
HAWT
2 or 3-bladed
Upwind or downwind
Land-based or offshore
Offshore monopiles or floating
Rigid or flexible foundation
FAST Verification
Participated in OC3, which compared the results of avariety of load cases for the OC3 HyWind Spar, with the
NREL 5 MW turbine placed on top.
New verification efforts are looking at understandinglimitations in the HydroDyn Module of FAST
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NATIONAL RENEWABLE ENERGY LABORATORY
STEP 2:Testing of 1/3 Scale Model at Test Site
13
Approximately 1/3rd Scale of5MW
Commercial turbine with provenrecord of performance is planned
~100 kW (will be provided). Floating platform designs willbe selected from competitiveindustry solicitation
Turbine will be deployed attimes when desired scaled wind/wave conditions are present.
100 1/3
1/3 Scale Prototype Monhegan Island
Approx. 2.5 miles south
from Monhegan Island
Up to 400 ft depth
9.0 m/s +averagewinds
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NATIONAL RENEWABLE ENERGY LABORATORY
Test Window for 1/3 Scale Turbine
15
52%
69%
56%A 47%
28%
7%
0%
A 1%
4%
46% 58%
D 73%
Current Status of 1/3 Scale
A Request for Interest (RFI) forindustry participation in testing planhas been released
Several submissions have beenreceived. Prequalification questionnaires
have been reviewed.
A Request for Proposals (RFP) iscurrently under development.
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FUNDACINCENTROTECNOLGICO DECOMPONENTES
SAEMar ProjectRal Rodrguez Arias
Head of Renewable Energies Unit
CTC
IEA R&D WIND TASK XI
Topical Expert Meeting #63on
HIGH RELIABILITY SOLUTIONS ANDINNOVATIVE CONCEPTS FOR OFFSHORE
WIND TURBINESSINTEF Energy Research, Trondheim, Norway
September 21-22 2010
SUMMARY
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1
CTC Presentation
Technological Centre of Components, CTC
CTC is a non-profit foundation and aims to contribute
to economic and social development, helping companies toassess the technological feasibility of their ideas, as well as
technically execute their R+D+I projects, as part of the
Science-Technology-Enterprise system.
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SAEMarProject
FACILITIES
CTC is located in the Scientific and Technological Park ofCantabria (PCTCAN), in an enabling environment for activitiesrelated to R & D.
5
The new facilities include a laboratory with equipment and
space necessary for project implementation and research.
2
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SAE
MarProject
SAEMar Project: an overview
7
SAEMar Project: Anchoring Systems for Renewable Marine EnergiesOffshore Platforms
National call: Fundamental and BasicResearch
Project Coordinator: CTC
Partners: Cantabria University and A CoruaUniversity
36 months (January 2011-December 2013)
Total budget: 811 K(420 k funded byMICINN)
3
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SAE
MarProject
Project's main objective and key points
9
Main objetive
The main objective of the project is to create a methodology for thereliable design of the system formed by the mooring line-anchor-soil ofFloating Ocean Energy Platforms (FOEP).
Key points
Probabilistic design (level III) of the system life cycle (mooring line-anchor-terrain)
Mechanical design and material selection.
Fatigue analysis using advanced probabilistic methods of fracturemechanics.
Dynamic terrain of the seabed and hydrodynamic analysis platforms.
Laboratory experimental program, including not only hydrodynamic
tests in a wave tank, but also geotechnical testing of the seabedterrain.
SAEMar Project: initial hypothesis
The main reason to present this proposal is to cover the gaps ofscientific knowledge and to develop a specific methodology forthe selection and improved design of anchoring systems for aFOEP.
The initial hypothesis which support the objectives are the
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SAE
MarProject
Specific objectives (I)
11
1. To develop specific methodologies for the analysis andselection of the suitable alternative of the anchoringsystem for an individual offshore floating moored platform.
2. Based on the previous objective, to adapt or develop
specific methodologies for the analysis and selection of the
suitable alternative of the anchoring system of a set of
platforms in a farm configuration.
3. To generate synergies in the knowledge of the
interrelationship mechanisms between the dynamics ofthe floating platforms, moorings systems, anchoring
systems and loads in the sea bottom materials.
PAGE11
Specific objectives (II)
4. Analyse different typologies of FOEPs, its anchoringsystems and the different sea bottom characteristics inorder to select some types for mooring lines forcesparameterization.
5. Analysis, parameterization and statistical descriptionh d l f f i h i
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4
Consortium and subprojects
Consortium and subprojects (I)
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SAE
MarProject
Consortium and subprojects (II)
15
Consortium and subprojects (III)
SP1 (CTC): Methodologies to select and design the anchoringsystem in FOEP
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SAE
MarProject
Consortium and subprojects (IV)
17
SP2 (UC): Hydrodynamics and Geotechnics of FOEP mooringSystems
Analysis, parameterization and statistical description (short and longterm) of the acting forces and loads in the mooring lines and anchorsdue to the combined actions induced by wind, waves and currents
Characterization of the response of the soil and its interaction withthe anchor
Consortium and subprojects (V)
SP3 (UDC): Life cycle and integration of FOEP mooring andanchoring system
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5
Work Packages and dissemination activities
Workpackages (I)
Preliminary analysis: platform and mooringconfiguration (UDC)
WP 1.2
Coordination and dissemination (CTC)WP 1.1
SP1: Methodolog ies to select and design the anchoring
system in FOEP
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SAE
MarProject
Workpackages (II)
21
Geotechnical tests (UC-GG)WP 2.3
Offshore geothecnical analysis (UC-GG)WP 2.2
Platform Hydrodynamics (UC-IH)WP 2.1
Mooring platform interface: analysis and design (UDC)WP 3.3
Life cycle analysis of the mooring and anchoring systems(UDC)
WP 3.2
Mooring design (UDC)WP 3.1
SP3: Life cycle and integration of FOEP mooring and
anchoring system
SP2:Hydrodynamics and Geotechnics of FOEP mooring
Systems
Work Packages and dissemination activities
Dissemination activities
Exploitation and dissemination of project results will be achieved
at 3 levels:
1. Within the project team, project advances and results will be
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Thank you for yourattention
Questions?
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23.09.2010
Taut mooring of floating wind turbines;
application examples and comparisons
(work in progress)
IEA Task XI Topical Expert Meeting 63, Trondheim,Norway, September 21-22, 2010
Tor Anders Nygaard
Institute for Energy Technology (IFE), Norway
Outline
Engineering challenges, floating wind turbines
Examples of conceptual designs
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Engineering Challenges
From the ocean engineers perspective: High thrust force andmass on top of structure giving overturning moment. The floatermust provide restoring moment to counteract this.
From the rotor aeromechanics engineers perspective: Largemotions compared to land-based or bottom-fixed towers. Windturbine suppliers are cautious about foundations with largemotions.
Strong coupling between aerodynamics, structural dynamics,hydrodynamics and control system
Strong cost constraints compared to the oil and gas industry
Examples
HYWIND
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23.09.2010
HYWINDSpar-buoy with catenary lines. Floater
restoring moment and rotor motion control
by large floater, heavy ballast and
innovative pitch controller. Inertia-
controlled motions.
5 MW version OC3-HYWIND definedfor model development and benchmarking
in the IEA-OC3 project.
Jonkman, J. et al (2010). Offshore Code
Comparison Collaboration within IEA
Wind Task 23. Europen Wind Energy
Conference & Exhibition, Warsaw, Poland,
April 2010.
SWAY
Pre-stressed tower/floater spar withdownwind turbine. Restoring moment
by the horizontal offset betweencenter-of buoyancy and effective
S i S b ibl Wi dFl t
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23.09.2010
Semi-Submersible - WindFloat
Restoring moment provided by heave
stiffness of three horizontally offset
cylinders.
Closed-loop water ballast system helps
maintaining vertical orientation of
tower.
Inertia- and damping control of motions.
Commercial development by Principal
Power Ltd.
Taut Line Buoy (TLB)Restoring moment and rotor
motion constraints by excessbuoyancy and prestressed taut
mooring in several heights.
All DOFs are stiffness-Wi d
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Previous work Worked with Christian Grorud from 2006, evaluating various
floaters with taut mooring in several heights:Nygaard, T. A., Myhr, A. and Maus, K. J. (2009). A comparisonof two conceptual designs for floating wind turbines. EuropeanOffshore Wind Conference & Exhibition, September 2009,
Stockholm, Sweden. The term TLB in the context of wind turbines appeared for the
first time in a paper by prof. Sclavonous, MIT at EWEC 2010:Sclavounos, P. D. et al.(2010). Floating wind turbines:Development of a Taught-Line-Buoy (TLB) concept. EuropeanWind Energy Conference (EWEC 2010), Warsaw, Poland, April2010
Motivation and aim
The aim is to develop cost-effective, stable platformsfor floating wind turbines, with properties comparableto bottom-fixed or onshore towers.
The savings in the floater could easily be lost due to
i d t f i li h d f t
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Approach
Design a TLB floater for the IEA 5MW referenceoffshore wind turbine.
Select mooring lines axial stiffness from Eigenfrequency analysis.
Determine pre-tension in the mooring lines, requiringthat a minimum level of pre-tension is maintainedduring a worst-case extreme event.
Run various load cases to estimate loads on the
mooring lines and anchors.
Example of TLB:
5MW application for 80m water depth
Above +10m: Identical to IEA OC3 5MW reference offshorewind turbine
Below +10m: Stripped down, ignoring redundancy and safetysystems, to provide estimate for maximum steel mass savings.D ft 50
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Eigen Frequency Analysis: Pitch : T = 4.9s
Surge: T = 2.3s
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Heave : T = 2.13s
First Bending : T = 0.94
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Second Bending : T = 0.46s
Extreme case:
Hs = 17m, Vhub = 65 m/s (steady)
Wave kinematics: Superposition of airy waves forfinite water depth, JONSWAP spectrum with peakperiod of 15.5 m/s. Phase, amplitude andwavenumber information is stored to provide identical
fi ld f h diff i l i
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Load case 5.1, IEA OC3
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,Regular airy waves, H = 6m T = 10s
Vhub = 11.4 m/s (steady)
Wave induced motion of nacelle causes power
variations, which in turn trigger pitch control actions,which in turn changes rotor trust, causing newmotions, and so on
Land based pitch controller was modified in IEA OC3project to provide stable behavior under operation
Both land-based and offshore controllers can be usedfor TLB
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TLB at other water depths
Continue upper ML down at same angle, 45 deg.Adjust EA to give same overall stiffness EA/L (fiberropes)
In this study, upper and lower ML are identical. Thisshould be studied closer, to optimize translatoryresponse to waves.
Example 2: TLB at 200m depth.
Upper and lower ML: Increase diameter with factor(200/80)**0.5 = 1.58. Otherwise identical
Ran same extreme case as earlier and comparedtower stresses to TLB at 80m depth
Comparison of TLBs at 80 and 200m depth
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23.09.2010
Comparison of TLB s at 80 and 200m depth
Proposed variations
For a downwind turbine, upwind upper mooringline(s) can take position almost up to hub height. Thiswould increase pitch stiffness, and reduce the needfor axial