Infrastructure Access Reports
Infrastructure: UNI-STRATH Kelvin Hydrodynamics Laboratory
User-Project: Aker WEC
Aker WEC prototype model test
Aker Solutions ASA
Marine Renewables Infrastructure Network
Status: FinalVersion: 02Date: 07-Feb-2014
EC FP7 “Capacities” Specific ProgrammeResearch Infrastructure Action
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 2 of 17
ABOUT MARINETMARINET (Marine Renewables Infrastructure Network for emerging Energy Technologies) is an EC-funded networkof research centres and organisations that are working together to accelerate the development of marine renewableenergy - wave, tidal & offshore-wind. The initiative is funded through the EC's Seventh Framework Programme (FP7)and runs for four years until 2015. The network of 29 partners with 42 specialist marine research facilities is spreadacross 11 EU countries and 1 International Cooperation Partner Country (Brazil).
MARINET offers periods of free-of-charge access to test facilities at a range of world-class research centres.Companies and research groups can avail of this Transnational Access (TA) to test devices at any scale in areas suchas wave energy, tidal energy, offshore-wind energy and environmental data or to conduct tests on cross-cuttingareas such as power take-off systems, grid integration, materials or moorings. In total, over 700 weeks of access isavailable to an estimated 300 projects and 800 external users, with at least four calls for access applications over the4-year initiative.
MARINET partners are also working to implement common standards for testing in order to streamline thedevelopment process, conducting research to improve testing capabilities across the network, providing training atvarious facilities in the network in order to enhance personnel expertise and organising industry networking eventsin order to facilitate partnerships and knowledge exchange.
The aim of the initiative is to streamline the capabilities of test infrastructures in order to enhance their impact andaccelerate the commercialisation of marine renewable energy. See www.fp7-marinet.eu for more details.
PartnersIreland
University College Cork, HMRC (UCC_HMRC)Coordinator
Sustainable Energy Authority of Ireland (SEAI_OEDU)
DenmarkAalborg Universitet (AAU)
Danmarks Tekniske Universitet (RISOE)
FranceEcole Centrale de Nantes (ECN)
Institut Français de Recherche Pour l'Exploitation dela Mer (IFREMER)
United KingdomNational Renewable Energy Centre Ltd. (NAREC)
The University of Exeter (UNEXE)
European Marine Energy Centre Ltd. (EMEC)
University of Strathclyde (UNI_STRATH)
The University of Edinburgh (UEDIN)
Queen’s University Belfast (QUB)
Plymouth University(PU)
SpainEnte Vasco de la Energía (EVE)
Tecnalia Research & Innovation Foundation(TECNALIA)
Belgium1-Tech (1_TECH)
NetherlandsStichting Tidal Testing Centre (TTC)
Stichting Energieonderzoek Centrum Nederland(ECNeth)
GermanyFraunhofer-Gesellschaft Zur Foerderung DerAngewandten Forschung E.V (Fh_IWES)
Gottfried Wilhelm Leibniz Universität Hannover (LUH)
Universitaet Stuttgart (USTUTT)
PortugalWave Energy Centre – Centro de Energia das Ondas(WavEC)
ItalyUniversità degli Studi di Firenze (UNIFI-CRIACIV)
Università degli Studi di Firenze (UNIFI-PIN)
Università degli Studi della Tuscia (UNI_TUS)
Consiglio Nazionale delle Ricerche (CNR-INSEAN)
BrazilInstituto de Pesquisas Tecnológicas do Estado de SãoPaulo S.A. (IPT)
NorwaySintef Energi AS (SINTEF)
Norges Teknisk-Naturvitenskapelige Universitet(NTNU)
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 3 of 17
DOCUMENT INFORMATIONTitle Aker WEC prototype model test
Distribution Public
Document Reference MARINET-TA1-Aker WEC
User-Group Leader, LeadAuthor
Anders Martin Moe Aker Solutions [email protected]
User-Group Members,Contributing Authors
Svein Ersdal Aker Solutions ASAØyvind Ygre Rogne Aker Solutions ASA
Infrastructure Accessed: UNI-STRATH Kelvin Hydrodynamics Laboratory
Infrastructure Manager(or Main Contact)
Charles Keay/Sandy Day
REVISION HISTORY
Rev. Date Description Prepared by(Name)
Approved ByInfrastructure
Manager
Status(Draft/Final)
01 01.02.13 Draft issue SveinErsdal/Anders M
Moe
Draft
02 07.02.14 Final issue Svein Ersdal Final
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 4 of 17
ABOUT THIS REPORT
One of the requirements of the EC in enabling a user group to benefit from free-of-charge access to an infrastructureis that the user group must be entitled to disseminate the foreground (information and results) that they havegenerated under the project in order to progress the state-of-the-art of the sector. Notwithstanding this, the EC alsostate that dissemination activities shall be compatible with the protection of intellectual property rights,confidentiality obligations and the legitimate interests of the owner(s) of the foreground.
The aim of this report is therefore to meet the first requirement of publicly disseminating the knowledge generatedthrough this MARINET infrastructure access project in an accessible format in order to:
progress the state-of-the-art
publicise resulting progress made for the technology/industry
provide evidence of progress made along the Structured Development Plan
provide due diligence material for potential future investment and financing
share lessons learned
avoid potential future replication by others
provide opportunities for future collaboration
etc.In some cases, the user group may wish to protect some of this information which they deem commerciallysensitive, and so may choose to present results in a normalised (non-dimensional) format or withhold certain designdata – this is acceptable and allowed for in the second requirement outlined above.
ACKNOWLEDGEMENT
The work described in this publication has received support from MARINET, a European Community - ResearchInfrastructure Action under the FP7 “Capacities” Specific Programme.
LEGAL DISCLAIMER
The views expressed, and responsibility for the content of this publication, lie solely with the authors. The EuropeanCommission is not liable for any use that may be made of the information contained herein. This work may rely ondata from sources external to the MARINET project Consortium. Members of the Consortium do not accept liabilityfor loss or damage suffered by any third party as a result of errors or inaccuracies in such data. The information inthis document is provided “as is” and no guarantee or warranty is given that the information is fit for any particularpurpose. The user thereof uses the information at its sole risk and neither the European Commission nor anymember of the MARINET Consortium is liable for any use that may be made of the information.
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 5 of 17
EXECUTIVE SUMMARYAker Solutions applied to Marinet for infrastructure access in spring 2012, and was awarded 3 weeks of access atthe Kelvin Hydrodynamics Laboratory, University of Strathclyde, Glasgow. A model of a proposed prototypeinstallation was tested during three weeks in December 2012.
The main goals of the tests was to correlate the internally developed numerical analysis model with the measuredresults, as well as to gain a better understanding of the prototype behaviour and survivability at the proposedlocation (Oslo fjord area, south east Norway).
The results from the model test of Aker WEC is compared with analytical results from a linear frequency domainanalysis. The focus is on the rotational response of the arm connecting the bodies, since this is the motion usedfor energy extraction. Using a servo motor with programmable torque vs. angular velocity characteristicsconstant, linear and quadratic relationships could be modelled. The comparison with the numerical model showsthat the presence of walls in the test tank influences the response, thus some uncertainty in the results is found.Still, the capture width is found to be above 30% of the width of the device for the most common waves. For longand large waves the efficiency is very low, which means that the PTO system is not overloaded in stormconditions. Comparison of the response with different characteristics of the PTO show that a quadratic relationgives an effective energy capture over a wide range of sea states with no tuning of parameters.
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 6 of 17
CONTENTS
1 INTRODUCTION & BACKGROUND...................................................................................................................7
1.1 INTRODUCTION ....................................................................................................................................................71.2 DEVELOPMENT SO FAR..........................................................................................................................................71.2.1 Stage Gate Progress .................................................................................................................................... 71.2.2 Plan For This Access..................................................................................................................................... 8
2 OUTLINE OF WORK CARRIED OUT...................................................................................................................9
2.1 SETUP.................................................................................................................................................................92.2 TESTS ...............................................................................................................................................................112.2.1 Test Plan ....................................................................................................................................................11
2.3 RESULTS AND DISCUSSION....................................................................................................................................122.3.1 Regular waves ...........................................................................................................................................122.3.2 Irregular Seastates ....................................................................................................................................132.3.3 Efficiency in irregular seas.........................................................................................................................142.3.4 PTO Characteristics ...................................................................................................................................14
3 MAIN LEARNING OUTCOMES .......................................................................................................................15
3.1 PROGRESS MADE ...............................................................................................................................................153.1.1 Progress Made: For This User-Group or Technology.................................................................................153.1.2 Progress Made: For Marine Renewable Energy Industry ..........................................................................15
3.2 KEY LESSONS LEARNED ........................................................................................................................................15
4 FURTHER INFORMATION..............................................................................................................................15
4.1 SCIENTIFIC PUBLICATIONS ....................................................................................................................................15
5 APPENDICES ................................................................................................................................................16
5.1 STAGE DEVELOPMENT SUMMARY TABLE ................................................................................................................16
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 7 of 17
1 INTRODUCTION & BACKGROUND
1.1 INTRODUCTION
Aker Solutions applied to Marinet for infrastructure access in spring 2012, and was awarded 3 weeks of access at theKelvin Hydrodynamics Laboratory, University of Strathclyde, Glasgow. A model of a proposed prototype installationwas tested during three weeks in December 2012.The main goals of the tests was to correlate the internally developed numerical analysis model with the measuredresults, as well as to gain a better understanding of the prototype behaviour and survivability at the proposedlocation (Oslo fjord area, south east Norway). A test using a different model was performed at NTNU in Trondheim in2011, and the results from the two tests will also be compared.
Modelling of the PTO system was one of the main challenges. Several options was considered, e.g. use of hydrauliccylinders, pneumatic cylinders etc., but we decided to use a servo drive operating only as a damper to ensure that noenergy was added to the system.
1.2 DEVELOPMENT SO FAR
1.2.1 Stage Gate ProgressPreviously completed: Planned for this project:
STAGE GATE CRITERIA Status
Stage 1 – Concept Validation
Linear monochromatic waves to validate or calibrate numerical models of the system (25 – 100 waves)
Finite monochromatic waves to include higher order effects (25 –100 waves)
Hull(s) sea worthiness in real seas (scaled duration at 3 hours)
Restricted degrees of freedom (DoF) if required by the early mathematical models
Provide the empirical hydrodynamic co-efficient associated with the device (for mathematical modellingtuning)
Investigate physical process governing device response. May not be well defined theoretically ornumerically solvable
Real seaway productivity (scaled duration at 20-30 minutes)
Initially 2-D (flume) test programme
Short crested seas need only be run at this early stage if the devices anticipated performance would besignificantly affected by them
Evidence of the device seaworthiness
Initial indication of the full system load regimes
Stage 2 – Design Validation
Accurately simulated PTO characteristics
Performance in real seaways (long and short crested)
Survival loading and extreme motion behaviour.
Active damping control (may be deferred to Stage 3)
Device design changes and modifications
Mooring arrangements and effects on motion
Data for proposed PTO design and bench testing (Stage 3)
Engineering Design (Prototype), feasibility and costing
Site Review for Stage 3 and Stage 4 deployments
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Rev. 02, 07-Feb-2014Page 8 of 17
STAGE GATE CRITERIA Status
Over topping rates
Stage 3 – Sub-Systems Validation
To investigate physical properties not well scaled & validate performance figures
To employ a realistic/actual PTO and generating system & develop control strategies
To qualify environmental factors (i.e. the device on the environment and vice versa) e.g. marine growth,corrosion, windage and current drag
To validate electrical supply quality and power electronic requirements.
To quantify survival conditions, mooring behaviour and hull seaworthiness
Manufacturing, deployment, recovery and O&M (component reliability)
Project planning and management, including licensing, certification, insurance etc.
Stage 4 – Solo Device Validation
Hull seaworthiness and survival strategies
Mooring and cable connection issues, including failure modes
PTO performance and reliability
Component and assembly longevity
Electricity supply quality (absorbed/pneumatic power-converted/electrical power)
Application in local wave climate conditions
Project management, manufacturing, deployment, recovery, etc
Service, maintenance and operational experience [O&M]
Accepted EIA
Stage 5 – Multi-Device Demonstration
Economic Feasibility/Profitability
Multiple units performance
Device array interactions
Power supply interaction & quality
Environmental impact issues
Full technical and economic due diligence
Compliance of all operations with existing legal requirements
1.2.2 Plan For This AccessThe main goal for this test is to investigate the prototype design behaviour and sea worthiness/survivability in realsea states relevant for the proposed test site. Further different PTO damping characteristics will be tested and theirinfluence on the device behaviour investigated.
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2 OUTLINE OF WORK CARRIED OUT
2.1 SETUP
The model is shown in Figure 1 and Figure 2.
Figure 1: The model in the tow tank. Wave probe, mooring lines and position reference ‘balls’ are visible. Picture is takenbefore bulwark was installed.
Figure 2: Model general arrangement
The instrumentation comprised:
Two wave probes, one in front and one between barge an tank wall.
6 DoF motion measurement of the Barge with an optical system (Qualisys)
Torque sensor at shaft
Hinge velocity and position from motor encoder
Video camera
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 10 of 17
All signals were logged on the in-house system by Cambridge Electronic Design (CED), and stored as time series ondisk. Post processing was done with CED’s own software during the test and with MATLAB afterwards.
To obtain flexibility and repeatability in the test the power take off was modelled by a servo motor and drive systemfrom Bosh Rexroth. The servo motor is connected to the shaft through a 4:1 gearbox as shown in Figure 2. The drivesystem comprised converter, motor controller and an integrated PLC control system, with PC based software forsetup and programming. An analogue output model provided encoder signal for the logging system.The idea of the power take system was to work as a feedback control system as illustrated in Figure 3
Figure 3 Principle of power take off system
In the test described hare, the controller used the angular velocity of the hinge shaft to set the braking torqueprovided by the motor. The motor was then always used as a generator; no compensation for e.g. friction wasincluded. The controller law implemented in the PLC controller is
T(ݐ) ൌ െܭ ห̇ߠห݊݃݅ݏ൫̇ߠ൯.
Here K and n are user specified parameters. The gain K was varied in to obtain maximum power output withallowable hinge amplitudes. The parameter n could be varied from 0 to 2 as will be discussed below. This isillustrated in Figure 4 Since the motor torque is used to break the motion, the relation is negative.
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 11 of 17
Figure 4: Ideal relation between PTO torque and angle velocity (Control Law)
This idealized PTO system will be used as a starting point for design of an actual PTO system.
2.2 TESTS
2.2.1 Test Plan
An overview of the regular and irregular wave tests are given in Table 1 and Table 2. The PTO setting refers to theparameters described above.
Table 1 Regular wave tests
-8
-6
-4
-2
0
2
4
6
8
-2 -1 0 1 2
Torq
ue
(Nm
)
Angular Velocity (rad/s)
n=0, K=3.8
n=1, K=4
n=2, K=6
Yaw
(deg) n K 0.7 0.8 0.8 0.9 0.9 1 1 1.1 1.2 1.3 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.2 Grand Total
Total 5 1 6 1 6 1 7 11 16 1 7 7 8 9 5 7 4 6 5 113
0 0 1 1 1 1 2 1 1 1 1 4 1 1 1 1 1 19
1.8 1 1 1 2 4 2 2 2 4 2 2 2 2 2 2 31
3.8 3 1 4
5.8 2 2
4 1 1 2 1 2 1 2 3 4 1 2 2 1 1 1 2 1 1 29
8 1 1 1 1 1 3 1 1 1 1 1 1 1 1 1 17
3 6 1 1 1 1 1 1 1 1 1 1 1 11
Total 1 1 1 1 1 1 1 1 1 1 1 11
2 4 1 1 1 1 1 1 1 1 1 1 1 11
6 1 7 1 7 1 8 12 17 1 8 8 8 10 5 8 4 7 5 124
Wave Period (s)PTO setting
Grand Total
1
2
0
30
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Rev. 02, 07-Feb-2014Page 12 of 17
Table 2 Irregular wave tests
The irregular wave trains were calibrated without the model in the tank. The model scale Hs and Tp is given in Table3.
Table 3 Calibrated wave series for irregular wave tests. All series is from JONSWAP spectrum
2.3 RESULTS AND DISCUSSION
2.3.1 Regular wavesAn important goal was to verify calculations of the response in the PTO system. The result from regular wave test forthe n=1 are shown in Figure 5. The curve for Mean, High and Low represents the measured results, where high andlow is the 9% confidence interval of measurements. The ‘Single’ curve is the result from numeric analysis.
Yaw
(deg) n K HS0
48
TP3
01
v2
HS0
48
TP4
50
v1
HS0
48
TP5
51
v1
HS0
48
TP6
51
v1
HS0
96
TP3
01
v2
HS0
96
TP4
51
v2
HS0
96
TP5
51
v2
HS0
96
TP6
51
v2
HS0
96
TP8
49
v2
HS1
50
TP1
24
7v1
HS1
50
TP4
50
v1
HS1
50
TP5
50
v1
HS1
50
TP6
51
v2
HS1
50
TP8
49
v1
HS2
50
TP1
25
v1
HS2
50
TP6
51
v1
HS2
50
TP8
49
v1
HS3
45
TP8
48
v1
HS4
00
TP8
49
v1
HS4
00
TP8
49
v1s3
HS4
00
TP8
49
v1s4
HS4
00
TP8
49
v1s5
HS4
00
TP8
49
v2s1
HS4
00
TP8
49
v2s6
Gra
nd
Tota
l
Total 5 2 1 1 5 1 11 1 3 2 1 2 5 4 1 1 3 1 2 1 1 1 1 1 57
1 0 1 1
1.8 1 1 1 1 1 5
3.8 1 1 1 1 1 1 6
5.8 1 1 1 3
2 2 1 1
4 1 1 1 1 1 1 7 1 1 1 16
8 1 1 1 1 1 1 6
16 1 1 1 1 1 5
20 2 1 1 1 1 1 7
3 6 1 1 1 1 1 1 1 7
Total 2 1 2
2 4 1 1 2
3 6 1 1
7 2 1 1 5 1 12 1 3 2 1 2 5 4 1 1 3 1 2 1 1 1 1 1 60Grand Total
PTO setting Calibarated Wave
0
30
No Wave Hs Tp Gamma Seed
1 HS048TP301v2 0.04 0.87 3.3 2
2 HS048TP450v1 0.04 1.3 3.3 2
3 HS048TP551v1 0.04 1.59 3.3 2
4 HS048TP651v1 0.04 1.88 3.3 2
5 HS096TP301v2 0.08 0.87 3.3 2
6 HS096TP451v2 0.08 1.3 3.3 2
7 HS096TP551v2 0.08 1.59 3.3 2
8 HS096TP651v2 0.08 1.88 3.3 2
9 HS096TP849v2 0.08 2.45 3.3 2
10 HS150TP550v1 0.125 1.59 3.3 2
11 HS150TP651v2 0.125 1.88 3.3 2
12 HS150TP849v1 0.125 2.45 3.3 2
13 HS150TP1247v1 0.125 3.6 3.3 2
14 HS250TP651v1 0.208 1.88 3.3 2
15 HS250TP849v1 0.208 2.45 3.3 2
16 HS250TP125v1 0.208 3.6 3.3 2
17 HS345TP848v1 0.288 2.45 3.3 2
18 HS400TP849v1 0.333 2.45 3.3 2
19 HS400TP849v1s3 0.333 2.45 3.3 3
20 HS400TP849v1s4 0.333 2.45 3.3 4
21 HS400TP849v1s5 0.333 2.45 3.3 5
22 HS400TP849v2s1 0.333 2.45 3.3 6
23 HS400TP849v2s6 0.333 2.45 3.3 6
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 13 of 17
Figure 5: Effect of wall by including mirror bodies at -4d, -2d, 2d, and 4d in the transverse direction.
The results are somewhat improved by including the effects of tank walls by placing mirror bodies in the numericmodel as illustrated by the last two curves in the figure.
2.3.2 Irregular SeastatesComparison of numeric and measured results for irregular waves are given in Figure 6. Again the mean curve is themean of the measured results and the error bars the 95% confidence interval. The discrepancies from the regularwaves are repeated here.
Figure 6: Measured and Calculated mean power output at the hinge for linear PTO
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Exp
ect
edP
ow
er
(W)
Mean
Single Body
4 Mirrors, d=2.6
4 Mirrors, d=2.0
Infrastructure Access Report: Aker WEC
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2.3.3 Efficiency in irregular seasThe efficiency in Error! Reference source not found. is here the ratio of the measured expected power and thepower of flux of the wave front times the width of the absorber. The device is found to be quite effective at lowperiods, less effective at higher. This is a design feature, since it means that the variation seen by the PTO system isreduced.
Table 4 Efficiency of the WEC in irregular seas
As mentioned in the description of the model test up, the PLC controller allowed for three value of n, the power ofthe angular velocity in the control law. The measured power for n=0, 1, and 2 are shown in Figure 7. In case of n=0and n=1, the gain factor is changed to obtain maximum output, for n=2 the factor is constant K=6.
2.3.4 PTO Characteristics
Figure 7: Mean and max power output on the hinge for different PTO control laws
The mean output for n=0 is on average 80% of the output for n=1. This means that an open loop, constant pressurehydraulic system is not optional from a performance point. On the other hand the peak power is quite low comparedto the other options.A quadratic characteristics (n=2) is the most effective option, on average 110% of the n=1 option. This is achievedwithout any changes in the gain factor for different sea states, thus a control system with input from environment isnot necessary. The price is very high peak pressures in some conditions.The linear relationship (n=1) is used when comparing models above, since this is the relationship in a linear numericmodel. But it also performs quite well, better than the constant force option but with same or lower peaks than thequadratic option. It do require control of the gain with input from the environment, but to a lesser extent than forn=0.
Hs (m) 0.87 1.3 1.59 1.88 2.45 3.6
0.04 35 % 37 % 24 % 13 %
0.08 40 % 35 % 25 % 17 % 19 %
0.125 21 % 15 % 19 % 18 %
0.208 8 % 13 % 15 %
0.288 11 %
0.333 9 %
TP (s)
Infrastructure Access Report: Aker WEC
Rev. 02, 07-Feb-2014Page 15 of 17
3 MAIN LEARNING OUTCOMES
3.1 PROGRESS MADE
The measured power production in small sea states is significantly higher than the predicted. Survivability in extremesea states has been verified. Damping characteristics for the PTO system has been evaluated.
3.1.1 Progress Made: For This User-Group or TechnologyConcept is verified, both with respect to production and survivability.
3.1.1.1 Next Steps for Research or Staged Development Plan – Exit/Change & Retest/Proceed?
Based on the test results, the current design will require only minor modification. Prototype to be developed andinstalled in the Oslo fjord. PTO system configuration to be developed for prototype. Will continue work with fundingfor a prototype.
3.1.2 Progress Made: For Marine Renewable Energy Industry Findings on influence of PTO system damping characteristics
Demonstrated that effect of walls in a tow tank must be considered.
An industry type servo motor and drive/controller gave a flexible setup with high repeatability.
3.2 KEY LESSONS LEARNED
The concept works as intended. The efficiency is high for small waves and low for large, meaning that thePTO system does not have to be design for the full load of a storm.
A quadratic relation between torque and angular velocity in the PTO gives a system that is effective over awide range of sea states with acceptable response limits. The same can be obtained with a linearrelationship, but the gain of system must be varied with respect to sea state. Constant torque has onlyabout 80% of the output compared to linear.
Any numeric model must capture the hydrodynamic coupling of bodies. The linear frequency domain modelused underestimated coupling between the two bodies for short periods. For other periods and steep wavesin particular, the model over predicted the output significantly.
Part of this discrepancy may come from the effect of walls. The test was conducted in a rather narrow towtank and the proximity of walls seems to influence the results. Compensating for this in the numeric model(by adding mirror bodies) demonstrated the effect but did not explain all discrepancies.
The use of an industrial type servo motor and drive/controller to model the PTO gave a flexible setup withgood repeatability.
4 FURTHER INFORMATION
4.1 SCIENTIFIC PUBLICATIONS
Ersdal, S; Moe, A: “Model Test of the Aker Wave Energy Converter Concept”, Proceedings of the ASME 201332nd International Conference on Ocean, Offshore and Arctic, OMAE2013, June 9-14, Nantes, France
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5 APPENDICES
5.1 STAGE DEVELOPMENT SUMMARY TABLE
The table following offers an overview of the test programmes recommended by IEA-OES for each TechnologyReadiness Level. This is only offered as a guide and is in no way extensive of the full test programme that should becommitted to at each TRL.
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