1. 2nd Asian Wave and Tidal Energy Conference (AWTEC-2014) Tokyo Big Sight, Japan 28 July-1 August 2014 www.awtec2014.org 2. WELCOME Dear AWTEC 2014 Delegates Welcome to the 2nd Asian Wave and Tidal Energy Conference (AWTEC) at Tokyo. This is following to the first ones in Jeju Island, Korea. It is our great honor and pleasure to have all of you at the occasion of Grand Renewable Energy 2014, which is one of the world-largest conferences which cover all kinds of renewable energy such as PV and on-land wind turbines with a slogan Advanced Technology Paths to Global Sustainability. AWTEC has been established to be the regional conference affiliated to the European Wave and Tidal Energy Conference (EWTEC) series, which has been running since 1979. The establishment of AWTEC is to facilitate the trans-national and regional sharing of knowledge and understanding from research activities being undertaken in the development of wave and tidal renewable energy systems, their interactions with the environment and the identification of barriers to be addressed in order to establish and marine renewable energy industry. AWTEC focuses on wave and tidal energy together with other ocean energy aspects of marine renewable energy technologies and recent activities. This second conference includes not only wave and tidal but also ocean thermal and floating wind turbines as well, because their research activities are very hot in Japan now. The conference aims to facilitate and provide opportunities for researchers, engineers, policy makers and stakeholders to exchange knowledge by profound discussions and recent research presentations and promote international and multi-disciplinary collaboration. Initially about 166 abstracts from 28 countries have been submitted and finally about 110 oral presentations and 43 poster presentations are selected for AWTEC 2014 program. This is very successful result reflecting the worldwide expectation to the huge potential of the ocean energy and their technology. Having the increased demand for the clean energy utilization in Asia and also realizing the tremendous potential of ocean energy resources in Asia, AWTEC will draw together regional activities in Asia and then interact and collaborate with the European sister conference series (EWTEC) for our mutual benefit. We would like to take this opportunity to express our sincere gratitude to the reviewers, committee members and sponsors for their contributions and dedications to make the successful conference. Prof. Takeshi Kinoshita Prof. Yusaku Kyozuka Chairman, AWTEC & OEAJ Chairman, Executive Committee AWTEC Nihon University Kyushu University 1 3. Dear AWTEC 2014 Delegate It is both an honour and with great pleasure in my capacity as Chairman of the Executive Committee of the European Wave and Tidal Energy Conference (EWTEC) I would like to extend a warm welcome to the 2nd Asian Wave and Tidal Energy Conference in Tokyo, Japan. AWTEC exemplifies the importance and value of international co-operation and the sharing of research outcomes and new understanding in the area of marine renewables. Never has there been a greater requirement for collaboration and the sharing of new knowledge and understanding in the harnessing of energies from the seas. Especially as we are about to see the first marine renewable arrays be deployed. There are a number of exciting research projects and technology development programs being undertaken in marine renewables and a number of these will be shared with delegates throughout this AWTEC. We continue to develop strong linkages between AWTEC and EWTEC in order to provide a platform for greater Asia-European research partnership and foster opportunities to enable greater levels of interaction, development of international research relationships, and the identification of new methodologies necessary in addressing the challenges associated with the development of a marine renewables industry. With the progressive evolution of AWTEC, we hope it continues to draw insight from EWTEC and its humble beginnings. I would like to take this opportunity to wish you a highly enjoyable conference and encourage you to take advantage of this international gathering and engage in the numerous events and discussions aiding the development of this exciting industry. Cameron Johnstone Chairman, Executive Committee European Wave and Tidal Energy Conference 2 4. ABOUT AWTEC2014 The Asian Wave and Tidal Energy Conference (AWTEC) has been established as the regional conference affiliated with the European Wave and Tidal Energy Conference Series (EWTEC). AWTEC was established to facilitate the transnational and regional sharing of knowledge and understanding from research activities concerning the development of wave and tidal renewable energy systems, their interactions with the environment and the identification of barriers to be addressed to establish the marine renewable energy industry. AWTEC will primarily focus on the wave and tidal energy aspects of marine renewable energy technologies and recent activities, but will also include other marine renewable energies, such as floating wind turbines and ocean thermal energy conversion. The conference aims to facilitate and provide opportunities for researchers, engineers, policy makers and stakeholders to exchange knowledge through profound discussions and recent research presentations and to promote international and multi-disciplinary collaboration. AWTEC2014 is held jointly with the Grand Renewable Energy Conference (GRE2014). GRE2014 is an international conference that brings together renewable energy technologies. Since 2006, the conference has been held every four years. GRE2014 is co-organized by many societies/institutes, including the Japan Council for Renewable Energy (JCRE) and the International Solar Energy Society (ISES), and is supported by the Japanese Ministries. During the conference, two exhibitions (PV Japan and the New Energy World Exhibition) are also held. 3 5. TECHNICAL TOPICS The conference topics listed below span the fields of wave and tidal energy research, ranging from technical issues through to cross-cutting policy, finance and environmental subjects Wave and tidal energy resource characterization Offshore wind and OTEC technologies Device development and testing Device hydrodynamics and structural mechanics Power take-off and device control Device and environmental modeling Environmental impact and appraisal Policy development and legislation Socio-economic impact Grid connection and system aspects Future markets and financing Smart grid technology 4 6. AWTEC MISSION STATEMENT Marine energy research, technology devices and commercial systems have risen rapidly in the last 10 years. From those experiences, there is an extensive understanding of the challenges and difficulties to be addressed for the successful development of a wave and tidal current power industry. To facilitate that development, AWTEC's key priorities will be Information sharing: Share and exchange information on the recent research and development and also testing protocols for the deployment of wave and tidal current power technologies leading to the acceleration of the marine energy industry and so to the development of a wider international marine power market. Harmonization of standards: Adopt common approaches and solutions for the generic components and systems of wave and tidal current power devices, where possible, so that related industries can benefit from these efforts and establish common solutions to aid the timely development of this international industry. This will be applied not only to the primary industries and supply chains but also to research and development parties. Policies: Promote the policies and supporting mechanisms of the countries/economies currently leading this development to widen the marine energy industry up-take to an international role. 5 7. GENERAL INFORMATION The Venue Tokyo Big Sight, also known as the Tokyo International Exhibition Center, is Japans largest exhibition and convention center and one of the bay islands boldest architectural creations. The venue is located within 30 minutes by train from central Tokyo. The area in which the venue is located (Odaiba) is a popular shopping and entertainment district on a man-made island in Tokyo Bay. Modern city planning provides Odaiba with some of Tokyos boldest architectural creations. Transportation Tokyo Big Sight is close to major airports, only about 60 minutes from Tokyo/Narita International Airport and about 25 minutes from Tokyo/Haneda Airport by airport bus. Please check transportation information at http://www.bigsight.jp/english/hotel/transportation/ Registration desk (ROOM601) The registration desk will be open on JUL28-31 from 09:00 to 17:00. The desk also opens on JUL27 from 16:00-18:00. AWTEC Opening (JUL28) The AWTEC opening is held at ROOM605 on JUL28 from 09:00-09:30 Welcome Reception (JUL28) The welcome reception will be at Hibiya Matsumotoro, Tokyo Big Sight 1st Floor, from 18:00 to 20:00. Oral/Poster presenters are welcome to join. Organizing Committee Meeting (JUL29) The organizing committee members are requested to join the OC meeting at the conference room from 18:00 to discuss on the various subjects of AWTEC. The conference room will be announced on JUL28. The future activities of AWTEC together with suggestions and comments to make AWTEC more successful and productive will be deliberated among the OC members from representing countries. Grand Renewable Opening Ceremony (JUL30) The ceremony is held at "Reception Hall A" from 10:30 to 12:30. Banquet (JUL30) The banquet will be held at "Reception Hall A" from 18:30. The ticket is not included for the student registration fee. The formal dress code is recommended for the banquet. 6 8. AWTEC Closing (JUL31) The AWTEC closing is held at ROOM701 on JUL31 around 15:10-15:30 Lunch Lunches are not included in the registration fee. Restaurants in Tokyo Big Sight http://www.bigsight.jp/english/services/shop/ TFT Building (Two minute walk from Tokyo Big Sight) http://www.tokyo-bigsight.co.jp/english/tft/wanza/restaurant/ Ariake Park Building (Two minute walk from Tokyo Big Sight) http://www.tokyo-bigsight.co.jp/english/park/restaurant/ Tours Please check http://www.grand-re2014.org/eng-conf/events/ Internet Access The free Wi-Fi is accessible in conference room. Network (SSID): Tokyo-BigSight_Wi-Fi Assistance and Staff Conference information and help will be available at the registration desk throughout the conference. Authors Information 1. Please check your session room before your presentation program. 2. Please check instructions for presenters at http://www.grand-re2014.org/eng-conf/instructions/ 3. The speaker is requested to meet the Chair at the session room before the session program. 4. Please make sure that your presentation file has been uploaded in the computer right before the session. 5. If there is any help you need, please contact the staff who will be available in the session room. 6. The time scheduled for each presentation is about 20 minutes including questions. 7. According to the decision of Chair, questions to the speaker are allowed at the end of each presentation or at the end of the session as long as the time permits. 8. Both Chair and speakers are requested to respect scheduled times. 9. Poster presenters are requested to stand in front of their poster panel during the session. 7 9. PROGRAM JUL28 ROOM 605 ID 9:30-10:00 Session 1: Opening Chair: Y. Kyozuka, Kyushu University, Japan T. Kinoshita (Chairman of AWTEC & OEAJ) C. Johnston (Chairman of EWTEC) Scottish Development International METI 10:00-10:40 Invited Talk (1) Research And Development Activities In Offshore Renewable Energy In The UK A. Incecik, University of Strathclyde, UK I1 10:40-11:20 Invited Talk (2) Global Marine Energy Technologies - Status And Future Prospects A. Bahaj, University of Southampton, UK I2 11:20-11:40 International Standardization for Offshore Renewable Energy H. Takano, ClassNK, JAPAN I3 11:40-13:00 Lunch 13:00-15:00 Session 2: Recent Progress Of Ocean Renewable Energy (1) Chair: T. Kinoshita, Nihon University, Japan EMEC - Current Status - Future Direction A. Davidson, The European Marine Energy Center S1 The Engineering Challenges In Delivering Robust, Cost Effective Technology For An International Tidal Energy Industry C. Johnstone, University of Strathclyde, UK S2 (1010) Recent Development Of Wave And Tidal Powers In Japan Y. Kyozuka, Kyushu University, Japan S3 Recent Development Of Otec In Asia And Pacific Ocean Y. Ikegami, Saga University, Japan S4 The Latest Progress Of Wave Energy In China And The Analysis Of Conversion Efficiency Considering PTO Damping H. Shi, Ocean University of China, China S5 (449) Recent Development Of Marine Renewable Energy In Korea Y.-H. LEE, Korea Maritime & Ocean University, Korea S6 15:00-15:20 Break 15:20-17:00 Session 3: Recent Progress Of Ocean Renewable Energy (2) Chair: Y.-H. Lee, Korea Maritime And Ocean University, Korea Status of Ocean Renewable Energy in Southeast Asia M. Abundo, Nanyang Technological University, Singapore S7 Projection Of Future Wave Climate For Marine Renewable Energy N. Mori, Kyoto University, Japan 682 Technical Development And Field Testing Of The Seaweed Micro-Wave Energy Converter For Development Application T. Nguyen, Tan Tao University, Vietnam 1012 Overcoming The Marine Energy Pre-Profit Phase: What Classifies The Game-Changing "Array-Scale Success" R. Bucher, University of Edinburgh, UK 53 Internal Waves And Associated Cooling Effect In Taiwan Coast G.-Y. Chen, National Sun Yat-sen University, Taiwan 420 17:00-17:55 Poster session (1) Room607 Presenters are requested to stand in front of their poster panel during the session. 18:00-20:00 Welcome Reception HIBIYA Matsumotoro (Tokyo Big Sight 1F) (Oral/Poster Presenter Only) 8 10. JUL29 ROOM 701 ID 9:00-10:40 Session 4: Ocean Current Energy Chair: S. Nagaya, IHI Corporation, Japan Design And Optimization Of A Marine Current Turbine M. Ahmed, The University of the South Pacific, Fiji 363 Submerged Hydraulic Turbine For Deep Marine Current As A Electric Power Generator K. Shirasawa, Okinawa institute of science and technology, Japan 381 Ocean Current Power Generating Apparatus Using Dual Duct As Boundary Effect Y.-Z. Kehr, National Taiwan Ocean University, Taiwan 470 Development Of Floating Type Ocean Current Turbine For Kuroshio Current S. Nagaya, IHI Corporation, Japan 638 Performance Prediction Of A Tilted Vertical Axis Marine Current Turbine A. Chowdhury, Korea Advanced Institute of Science and Technology, Korea 661 10:40-10:50 Break 10:50-12:10 Session 7: Ocean Thermal Energy Conversion Chair: Y. Ikegami, Saga University, Japan Effect Of Phase Shift Of A Sinusoidal Plate Heat Exchanger On The Heat Transfer Characteristics M. R. Ahmed The University of the South Pacific, Fiji 346 Comparison Between The Conventional Method And A New Developed Method For Calculating A Multi-Stage Rankine Cycle T. Morisaki, Saga University, Japan 458 Experimental Otec Study Using A Double-Stage Rankine Cycle E. Kusuda, Saga University, Japan 536 Heat Transfer Enhancement Using Microfabricated Surface On Plate Heat Exchanger Y. Kawabata, Saga University, Japan 572 12:10-13:10 Lunch 13:10-15:10 Session 10: Ocean Resource (1) Chair: D. Kitazawa, The University Of Tokyo, Japan Proposed Methodology For As Cost Synergies Between Offshore Renewable Energy And Other Sea Uses L. Margheritini, 1-Tech, Belgium 937 Characterization Of The Tidal Current Resource In Tasmania R. Rahimi, University of Tasmania, Australia 44 Feasibility Study On The Application Of Ocean Energy K. Inoue, The Society of Ocean Romantics, Japan 466 Evaluations Of Ocean Renewable Energy Potential By The Theoretical Capacity Factor Around Japan T. Taniguchi, National Maritime Research Institute Japan 502 Assessments Of Wave Energy Resource From The Deep Sea to The Coastal Area Of Gulf Of Thailand W. Wannawong, Hydro and Agro Informatics Institute Thailand 645 Supporting The Development Of A Marine Energy Industry In Japan Y. Uchida, Garrad Hassan Japan Ltd., Japan 279 15:10-15:20 Break 15:20-18:00 Session 13: Tidal Energy (4) Chair: C.-K. Rheem, The University Of Tokyo, Japan (To be assigned) Effect Of The Velocity Profile Of Incoming Flow On The Performance Of A Horizontal Axis Tidal Stream Turbine Cora Fung, University of Sheffield, UK 73 Dynamic Testing Of A 1/20Th Scale Tidal Turbine K. Gracie, Dalhousie University, Canada 1011 Experiments And Numerical Analysis Of A Marine Current Turbine I.-C. Kim, Korea Maritime and Ocean University, Korea 361 Conceptual Designs Of A Novel Type Of Folding Tidal Turbine A. Bhatia, University of Malaya, Malaysia 428 Tidal In-Stream Turbine For Slow Moving Water: Potential Of Superhydrophobic Coating K.-W. Ng, University of Malaya, Malaysia 429 Blockage-Enhanced Performance Of Tidal Turbine Arrays J. Schluntz, University of Oxford, UK 506 On The Interaction Of Tidal Power Extraction And Natural Energy Dissipation In An Estuary M. Kawase, University of Washington, USA 585 Performance Characteristics Of A Counter-Rotating Tidal Current Turbine By The Variation Of Blade Angle N.-J. Lee. Korea Maritime and Ocean University, Korea 333 9 11. JUL29 ROOM 801 ID 9:00-10:40 Session 5: Tidal Energy (1) Chair: C. Jo, Inha University Korea Performance Variation Of The Horizontal Axis Tidal Turbine By Blade Deformation K.-H. Lee, Inha University, Korea 636 Energy Harvesting By Flow-Induced Vibration Of Hydro-Venus Converter S. Hiejima, Okayama University, Japan 22 Turbulence And Its Effects On The Thrust And Wake Of A Porous Disc Rotor Simulator T. Blackmore, University of Southampton, UK 52 Marine Current Turbine Performance And Wake Evolution With Changes In Channel Geometry B. Keogh, University of Southampton, UK 86 Numerical Simulation Of Straight-Bladed Vertical Axis Tidal And Current Turbines P. Marsh, University of Tasmania, Australia 241 10:40-10:50 Break 10:50-12:10 Session 8: Tidal Energy (2) Chair: C. H. Tsai, National Taiwan Ocean University, Taiwan Scale Experimental Modelling Of A Multiple Row Tidal Array K. Shah, University of Southampton UK 272 2 Dimensional Depth Averaged Numerical Modeling Of Large Marine Current Turbine Arrays C. Daniel, University of Southampton UK 290 Tidal Current Power Potential In Goto Islands By Observations And Simulations H. Sun, Kyushu University, Japan 421 Tidal Energy Research In The Straits Of Malacca W.H. Lam, University of Malaya Malaysia 426 12:10-13:10 Lunch 13:10-15:10 Session 11: Tidal Energy (3) Chair: C. Johnstone, University Of Strathclyde, UK Development And Deployment Of Ocean Renewable Energies: An Integrated Strategic Framework H.-Y. Chong, Universiti Tunku Abdul Rahman, Malaysia 427 Tidal Stream Power Potential Off Cape Fuguei In Northwestern Taiwan C.-H. Tsai, National Taiwan Ocean University, Taiwan 435 Study On The Influence On The Wake Of Horizontal Axis Tidal Turbines In Tidal Power Farm Considering Different Factors J. Tan, Ocean University of China, China 546 Effects Of The Number Of Blades On Performances Of A Variable-Pitch Type Vat T. Ikoma, Nihon University, Japan 595 Physical And Numerical Model Test For VAT (Verfical Axis Turbine) And Pile-Supported Breakwater K. Ko, Hyundai Engineering and Construction Co., LTD., Korea 608 A Study Of Tidal Current Energy Capture System: Penghu Case B.-F. Chen, National Sun Yat-sen University Taiwan 797 15:10-15:20 Break 15:20-18:00 Session 14: Tidal Energy (5) Chair: A. Bahaj, University Of Southampton, UK, W. H. Lam, University Of Malaya, Malaysia Numerical Simulation Of A Pilot Tidal Farm Using Actuator Disks, Influence Of A Time-Varying Current Direction V. Nguyen. Normandy University. France 784 Diffuser Shape Optimization For Gem, A Tethered System Based On Two Horizontal Axis Hydro Turbines D. Coiro, University of Naples "Federico II", Italy 720 Experimental And Numerical Analysis Of Horizontal Axis Tidal Power Turbine With Fixed Yaw And Pitch T. Hirobe, The University of Tokyo, Japan 947 Hydrodynamic Analysis And Design Of Marine Current Turbine Blades C.-Y. Hsin, National Taiwan Ocean University Taiwan 948 Simulating The Flow Field Around The Marine Current Turbine By The Body Force Method C.-. Hsin, National Taiwan Ocean University Taiwan 949 Experimental Study On Optimal Shape Of Ellipsoidal Cross Section Cylinder Of Translational Vortex Induced Vibration Energy Extraction Device J.-S. Choi, Korea Research Insfitute of Ships and Ocean Engineering, Korea 970 Computational Investigation Using Simple RANS Model on the Performance of a Novel Marine Turbine: Hydro Spinna R. Rosli, Newcastle University, UK 985 Cyclic Loading Analysis Of Tidal Current Turbine As Per Variable Gabs Between Turbine And Tower S.-J. Hwang, Inha University, Korea 532 10 12. JUL29 ROOM 802 ID 9:00-10:40 Session 6: Wave Energy (1) Chair: S. Nagata, Saga University, Japan Hybrid Seawave And Solar Energy Converter N. Andres, Bataan Peninsula State University, Philippines 46 Phase Averaging Of PIV Flow Fields Of An Oscillating Water Column In Polychromatic Waves T. Ferguson, University of Tasmania, Australia 49 Numerical Simulation Of A Scaled Down Oscillating Water Column Wave Energy Convertor J. Wata, Korea Maritime and Ocean University, Korea 298 Numerical Analysis Of Full Scale Floating Wave Energy Converter And Comparison With Its SmallScale Model B. Kim. Korea Maritime and Ocean University. Korea 324 Advance In The Study Of Wave Energy Dissipation Of Floating Bodies W.-C. Chen, University of Tsinghua, China 515 10:40-10:50 Break 10:50-12:10 Session 9: Wave Energy (2) Chair: H. Shi., Ocean University China, China In-Situ Orifice Calibration For Oscillating w And Improved Performance Prediction In Oscillating Water Column Model Test Experiments A. Fleming, University of Tasmania, Australia 81 Wave Energy Converter As An Anti-Motion Device For Floating Offshore Wind Turbine K. Liao, Kyushu University, Japan 442 Project Of The Blow Hole Wave Power Generator System On The Echizen Shore T. Miyazaki, The University of Tokyo Japan 476 FSI Analysis On Buoy For A 30Kw Wave Energy Converter Y.-D. Choi, Mokpo National University, Korea 522 12:10-13:10 Break 13:10-15:10 Session 12: Wave Energy (3) Chair: A. Incecik, University Of Strathclyde, UK Cape-Verde Offshore Wave Energy Resources Characterization W. Monteiro, University of Cape-Verde, Republic of Cape Verde 725 Numerical And Experimental Tests On A Scaled Model Of A Point Pivoted Absorber For Wave Energy Conversion D. Coiro, University of Naples "Federico II", Italy 726 Design Load Cases For Wave Energy Converters J. Cruz, DNV GL-Energy, Portugal 885 Optimization Of A Magnetostrictive Wave Energy Harvester T. Mundon, Oscilla Power, USA 956 Frequency Domain Study On Multi-Chamber Oscillating Water Columns P. Koirala, Saga University, Japan 533 Experimental Study On Energy Conversion Efficiency Of PW-OWC Type Wave Power Extracting Breakwater K. Shimosako. Port and Airport Research Institute. Japan 554 15:10-15:20 Break 15:20-18:00 Session 15: Wave Energy (4) Chair: I. Penesis, University Of Tasmania, Australia T. Miyazaki, The University Of Tokyo, Japan Optimal Control Of The Oscillating Body Type Wave Energy Converter Under Limited Mechanical And Conversion Capacity D. Matsuda, The University of Tokyo, Japan 540 Assessment Of Wave Energy Potential At The Shores Of Sinop, Black Sea, Turkey M. Akgul, Istanbul Technical University, Turkey 674 Model Test Of SPA-OWC Wave Energy Converter S. Song, Yonsei University, Korea 925 A Time-Domain Analysis Algorithm For Multibody WEC Systems D. Padeletti, NUI Maynooth, Ireland 987 Global Structural Response Of Floating Pendulum Wave Energy Converter J.-M. Sohn, Korea Research Institute of Ships & Ocean Engineering, Korea 950 Effect Of Load On Primary Conversion Efficiency Of A Floating Type Pendulum Wave EnergyConverter T. Murakami, Saga University, Japan 986 Wave Energy Converter Experience: The Deployment Of The Drakoo-B0016 Pilot Project H. Han, Hann-Ocean Energy Pte Ltd., Singapore 766 Numerical Simulation On Hydrodynamic Motion Response For Floating Hybrid Power Generation System In Waves S.-W. Park, Korea Research Institute of Ships & Ocean Engineering, Korea 962 11 13. JUL30 ROOM 605 ID 9:00-10:20 Session 16: Tidal Energy (6) Chair: S. Yamaguchi, Kyushu University, Japan Tidal Current Energy Map Around Kyushu-Okinawa Region Japan S. Yamaguchi, Kyushu University, Japan 474 Channel Scale Optimisation Of Large Tidal Turbine Arrays In Packed Rows Using Large Eddy Simulations With Adaptive Mesh T. Divett, University of Otago, New Zealand 939 Three Dimensional Simulation Of Horizontal Axis Tidal Turbine - Comparison With Experimental Results D. Groulx, Dalhousie University Canada 512 Causes Of Tidal Turbine Main Bearing Failure K. Karikari-Boateng, Industrial Doctorate Centre in Offshore Renewable Energy, UK 630 10:20-10:30 Break 10:30-12:30 Grand Renewable Opening And Keynote Reception Hall A (Tokyo Big Sight 1F) 12:30-13:30 Lunch 13:30-15:30 Session 17: Wave Energy (5) Chair: K. Shimosako, Port And Airport Research Institute, Japan Numerical Assessment Of Three Flexibly Mounted Rotary Wave Energy Converters With A Two Degree Of Freedom Constraint E. Odhiambo, National Taiwan University of Science and Technology, Taiwan 617 Risk Based Estimation Of Failure In A Steel Wire Used For The Wave Energy Converter Connection Line I. Dolguntseva, Uppsala University, Sweden 933 Flexibles Articulations For WEC And TEC - Lessons From Oil & Gas And Other Marine Installation A. Skraber, Hutchinson - Techlam, France 652 Impulse Turbines: A Review And Assessment Of Their Utilization In Overtopping Wave Energy Converters M. Akaul, University of Strathclyde, UK 1015 Structural Analysis Of Pendulum Mounting Unit For Floating Pendulum Wave Energy Converter H. Cheon, Korea Research Institute of Ships & Ocean Engineering, Korea 977 Experimental Study Of Wave-Induced Motion And Performance For Floating Pendulum Wave Energy Converter J. Park, Korea Research Institute of Ships & Ocean Engineering, Korea 975 15:30-15:40 Break 15:40-16:40 Session 18: Ocean Resource (2) Chair: B.-F. Chen, National Sun Yat-Sen University, Taiwan A Study On The Propriety Of Commercial Tidal Current Power Plant At The Southwest Coast Of Korea S. Han, Korea Institute of Ocean Science and Technology, Korea 934 Shelf Sea Modelling Of Renewable Energy Arrays H. Buckland, National Oceanography Centre, UK 957 Unsinkable-Stable Unaffected From Waves Floating Truss Platforms (Unflop) T. Andrikopoulos, Advanced Technical Innovations Organization-ATIO Group, Greece 900 16:40-17:40 Poster Session (2) Room607 Presenters are requested to stand in front of their poster panel during the session. 18:00-20:00 Conference Banquet Reception Hall A (Tokyo Big Sight 1F) 12 14. JUL31 ROOM 610 ID 9:00-10:40 Session 19: Wave Energy (6) Chair: Y. Yasuzawa, Kyushu University, Japan Engineering On The Cost Saving For Energy Of The Ocean Waves T. Watabe, T-Wave Consultant, Japan 701 Multiple Resonance Oscillating Water Column System For Wave Power Conversion --- R/D Towerd The Practical Application K. Kihara, Mitsubishi Heavey Industries Bridge & Steel Structures Engineering, Japan 758 Validation Of CFD Simulation Of The Drakoo Wave Energy Converter Power Take-Off DE-RIJK Leendert, Hann-Ocean Energy Pte Ltd., Singapore 767 Benchmarking Of The New Design Tool Inwave On A Selection Of Wave Energy Converters From Numwec Project A. Combourieu, INNOSEA, France 941 Phase-Averaged Analysis Of An Oscillating Water Column In Polychromatic Waves I. Penesis, University of Tasmania, Australia 1038 10:40-10:50 Break 10:50-12:10 Session 20: Wave Energy (7) / Offshore Wind Chair: M. Murai, Yokohama National University, Japan A Study On Oscillating Foil Energy Harvester With A Passive Flexible Foil Q. Xiao, University of Strathclyde, UK 657 Study Of Energy Storage And Stabilization Technology Based On Wave Energy Hydraulic Pump H. Yu, University of Tsinghua, China 514 Development Of Offshore Wind Power Forecasting System To Evaluate Wind Resources Around Japan Y. Morinishi, Nagoya Institute of Technology, Japan 114 Factors Promoting Agreement Of The Offshore Wind Project Among Fishermen In Japan M. Motosu, Nagoya University Japan 197 JUL31 ROOM 701 ID 13:10-15:10 Session 21: Offshore Wind (1) Chair: T. Chujo, National Maritime Research Institute, Japan Effect On The Offshore Wind Turbine Loads In Winter High Turbulence Conditions Y. Tsugawa, The University of Tokyo, Japan 367 Experimental Study On Distribution Of Internal Forces In Supporting Structure Of Floating Offshore Wind Turbine C. Hirao, National Maritime Research Institute, Japan 504 Water Jetting Application To Jackup Barge Spudcan Extraction In Clayey Soils D.-Y. Kim, Inha University, Korea 547 Development Of New Floating Platform For Multiple Ocean Renewable Energy C. Hu, Kyushu University, Japan 792 Spatial Distribution Of Hydrodynamic Response Of Floating Offshore Wind Farm In Waves M. Murai, Yokohama National University, Japan 641 A Fundamental Study On Responses Of Underwater Plaform In Waves K. Haneda, National Maritime Research Institute Japan 642 15:10-15:30 AWTEC Closing 15:30-17:40 Young Researcher's Meeting (INORE) 13 15. JUL31 ROOM 605+606 ID 14:30-17:20 Session: Offshore Wind (2) Acceptance And Social Impact Of Offshore Wind Power - Results From A Longitudinal Study H. Gundula, Martin-Luther-University Halle-Wittenberg, Germany 1021 Characteristics Of The Observed Data Off The Kita-Kyusyu City Ocean Observation Tower System H. Tsukiji, Electric Power Development Co.,Ltd Japan 203 A Robust Concrete Floating Wind Turbine Foundation For Worldwide Applications T. Choisnet, Ideal, France 371 Development Of The World's Largest Dynamic Cable System For Offshore Floating Wind Power S. Fujii, Furukawa Electric Co.,Ltd, Japan 483 (4 papers will be added) AUG1 ROOM 605+606 ID 8:30-9:30 Session: Offshore Wind (3) Experimental Study On The Negative Damping In The Dynamic Responses Of Blade-Pitch-Controlled Floating Offshore Wind Turbine T. Chujo, National Maritime Research Institute Japan 658 Sampled-Data Control For Avoiding Tower Pitching Motion And Wave Power Generation In Offshore Wind Turbine By Rotation Manipulation Function S. Kotake, Mie University, Japan 927 Demonstration Experiment Of Offshore Wind Power Generation By A Hexagonal Floating Platform In Hakata Bay Y. Kyozuka, Faculty of Engineering Sciences, Kyushu University 418 14 16. POSTER SESSION POSTER SESSION (1) JUL28, 17:00-18:00, ROOM607 ID Design And Research Of The Resonance Based Oscillation Buoy Wave Power Device J. Chen, Wuhan University, China 267 Air Comprssibility Efects On OWC Type Wave Power Generation M. Suzuki, University of the Ryukyu, Japan 350 Evaluation Of Damping Strategies For Maximum Power Extraction From A Wave Energy Converter With A Linear Generator S. Apelfroejd, Uppsala University, Sweden 392 Water Tank Testing On Hold Angle Of Cylindrical Oscillating Water Column In Wave Energy Converter M. Iino, The University of Tokyo, Japan 479 Improved Control Method Of Wells Turbine For Wave Energy Power Generators T. Kikuchi, Fuji Electric Co.,Ltd., Japan 485 Numerical Analysis Of Stall-Delay Turbine For Wave Energy Conversion System J. Nakamura, Fuji Electric Co.,Ltd., Japan 497 Control System For Mean Sea Level Variation Compensator At The Lysekil Research Site V. Castellucci, Uppsala University, Sweden 543 Configuration Of The Single-Bucket Wave Turbine For The Direct Utilization Of Orbital Fluid Motion H. Akimoto, Korea Advanced Institute of Science and Technology, Korea 600 Scour Prediction Of Tidal-Current Turbine: Inclusion Of Flow Field Generated By Rotor L. Chen, University of Malaya, Malaysia 430 A Survey On Public Acceptance Of Marine Renewable Energy In Malaysia X. Lim, University of Malaysia, Malaysia 431 Statistical Analysis In The Wake Of A Tidal Stream Turbine S. Walker, University of Sheffield UK 453 Design Optimization Of Leading-Edge Tubercles As Applied On A Tidal Turbine Blade W. Shi, Newcastle University, UK 465 Analytic Approach To Opzimization Of Tidal Turbine Fields D. Volk, Technische Universitaet Darmstadt, Germany 510 Resource Assessment Of Tidal Energy Of The Tsugaru Strait R. Wada, The University of Tokyo, Japan 550 Sustainability Of Tidal Energy M. Kawase, University of Washington USA 584 The Power Potential Of A Tidal Turbine Array With Turbine Power Capping C. Vogel, University of Oxford, UK 599 Heat Exchanger Performance And Its Effect At Okinawa OTEC Facility S. Okamura, Xenesys Inc., Japan 625 Long Term Load Forecasting For Ocean Thermal Energy Conversion Using Neural Networks M. Ibraheem, University Malaysia Terengganu, Malaysia 689 Tidal Turbine Control System For Hybrid Integration And Automatic Fluctuation Compensation Of Offshore-Wind Turbine Generation System M. Rahman, Kyoto University, Japan 322 A Basic Study Of Attitude Stabilization Of A Floating Wind Turbine By Wave Energy Conversion Control T. Kamio, The University of Tokyo, Japan 335 Pt-Coated Woven Mesh Spacer With Improved Mass Transport In Reverse Electrodialysis D. Kim, Korea Institute of Energy Research Korea 879 Verification And Validation Of Tidal Resource Assessment Model For A Strait Between An Island And A Landmass A. Ortiz, Industrial Doctral Centre for Offshore Renewable Energy, UK 390 15 17. POSTER SESSION (2) JUL30, 16:40-17:40, ROOM607 ID Using Artificial Neural Networks For Prompt And Accurate Wave Prediction At Northwest National Marine Renewable Energy Center's North Energy Test Site: A Feasibility Analysis B. Boren, Oregon State University, USA 621 Hydrodynamic Optimization On The Three Kind Of Buoy For A Point Absorber Wave Energy Converter By Boundary Element Method M. Berenjkoob, Amirkabir University of Technology, Iran 683 A Demonstration Project Of Wave-Power Generation Systems S. Watanabe, Mitsui Engineering & Shipbuilding Co., Ltd, Japan 750 Active Magnetic Bearings Using Air-Cored Coils Halbach Array In A Linear Wave Energy Converter J. Barajas-Solano, University of Edinburgh UK 779 Suppression Of Galloping And Direct Electric Generation From Overhead Transmission Line Oscillations By Using Vibration Manipulation Function S. Kotake, Mie University, Japan 926 Optimization Of Linear Generator For Point Absorber Using Response Surface Method J. Kim, Yonsei University, Korea 932 Floating Pendulum Wave Energy Converter (FPWEC) Combined Monitoring System Plan C.-H. Lim, Korea Research Institute of Ships & Ocean Engineering, Korea 969 Studies On Small-Sized Efficient Rotating Machine For Tidal Power Generation M. Izumi, Tokyo University of Marine Science and Technology, Japan 835 Feasibility Study In Order To Build Test Bed Of Tidal Current Power At Korea T.-G. Hwang, Korea Marine Equipment Research Institute, Korea 851 Demonstration Of A Condition Monitoring System For Tidal Energy Converters. Challenges, Solutions And Results Of First Demo P. Mayorga, EnerOcean S.L., Spain 951 Design Points And Current Situation Of Horizontal Axis Tidal Current Energy Turbine Blade Z. Dai, Shenyang Windpower Equipment Development LLC, China 967 A Full Rotor Simulation And Performance Analysis Of 10Kw Scale Tidal Turbine A. D. Hoang, Mokpo Maritime University, Korea 992 Study On Active/Passive Hybrid Type Yaw Control Device Using Rudder At Tidal Current Power System T.-G. Hwang, Korea Marine Equipment Research Institute Korea 851 New Design Power Generation System Installed In Artificial Fish Reef H. Nanjo, Hirosaki University, Japan 529 How To Further An Ocean Current Generation Development In Aomori Prefecture M. Shimada, Hirosaki University, Japan 601 Lure-Type Ocean And Tidal Current Power Generation Apparatus M. Yasukagawa, Senryo Corp., Japan 1004 Advancement Of A Distributed Adaptive Mobile Ocean Energy Recovery System A. Gizara, Integrated Power Technology Corporation, USA 336 A Suggestion Of Pitch Control To Avoid Negative Damping Of Floating Offshore Wind Turbine By Dynamic Analysis Y. Tamagawa, The University of Tokyo, Japan 489 Offshore Wind Power Generation (Offshore From Kitakyushu City) S. Nakashima, Electric Power Development Co., Ltd., Japan 722 Power Supply Of Perspective Complexes Mariculture V. Knyazhev, Institute of Marine Technology Problems FEB RAS, Russia 253 On The Climatology Of Wave Energy Resources Around Japan W. Sasaki, Japan Agency for Marine-Earth Science and Technology, Japan 88 Conversion Of Internal Energy Of Natural Solutions In The Ocean V. Knyazhev, Institute of Marine Technology Problems FEB RAS, Russia 252 16 18. AWTEC COMMITTEE Organizing Committee Dr. Irene Penesis University of Tasmania, Australin Maritime College (Australia) Dr. Chee Ming Lim Universiti Brunei Darussalam (Brunei Darussalam) Prof. Shi Hongda Ocean University China (China) Dr. Weimin Liu The First Institute of Oceanography (China) Dr. Rafiuddin Ahmed University of South Pacific (Fiji) Prof. Johnny C.L. Chan City University of Hong Kong (Hong Kong) Prof. K.W. Chow The University of Hong Kong (Hong Kong) Dr. Mukhtasor Indonesian Ocean Energy Association (Indonesia) Prof. Kyozuka Yusaku Kyushu University (Japan) Prof. Shuichi Nagata Saga University (Japan) Prof. Takeshi Kinoshita Nihon University (Japan) Chair Prof. Young-Ho Lee Korea Maritime and Ocean University (Korea) Prof. Chul H. Jo Inha University (Korea) Dr. Seung Ho Shin Korea Institute of Ocean Science and Technology (Korea) Dr. Omar Yaakob Universiti Teknologi Malaysia (Malaysia) Dr. Lim Yun Seng Universiti Tunku Abdul Rahman (Malaysia) Dr. Myat Lwin Myanmar Maritime University (Myanmar) Mr. Htun Naing Aung Union of Myanmar of Federation of Chambers of Commerce and Industries, Energy and Environment Cluster Group (Myanmar) Dr. Laura David University of the Philippines (Philippines) Dr. Sutthiphong Srigrarom University of Glasgow Singapore (Singapore) Dr. Michael Lochinvar Abundo Nayang Technology University (Singapore) Prof. Cheng Han Tsai National Taiwan Ocean University (Taiwan) Dr. Kehr Young-Zehr Ship and Ocean Industries R&D Center, National Taiwan Ocean University (Taiwan) Prof. Chen Bang-Fuh National Sun Yat-San University (Taiwan) Dr. Chaiwat Ekkawatpanit King Mongkut University of Technology Thonburi (Thailand) Dr. Pham Hoang Luong Hanoi University of Science and Technology (Vietnam) Mr. Nguyen Binh Khanh Vietnam Academy of Science and Technology (Vietnam) EWTEC Advisory Committee Dr. Cameron Johnstone University of Strathclyde (UK) Dr. Gareth Thomas University College Cork (Ireland) Prof. AbuBakr Bahaj University of Southampton (UK) Dr. Peter Frigaard Aalborg University (DK) Dr. Alain Clement Ecole Central de Nantes (France) Local Committee Prof. Chang-Kyu Reem University of Tokyo (Japan) Prof. Daisuke Kitazawa University of Tokyo (Japan) Dr. Hiroyuki Ohsawa Japan Agency for Marine-Earth Science and Technology (Japan) Prof. Ken Takagi University of Tokyo (Japan) Dr. Kenichiro Shimosako Port & Airport Research Institute (Japan) Prof. Motohiko Murai Yokohama National University (Japan) Dr. Shogo Miyajima Akishima Laboratories, Mitsui Zosen Inc. (Japan) Prof. Shuichi Nagata Saga University (Japan) Prof. Takeshi Kinoshita Nihon University (Japan) Prof. Takeaki Miyazaki -University of Tokyo (Japan) Prof. Tomoki Ikoma Nihon University (Japan) Prof. Yukitaka Yasuzawa Kyushu University (Japan) Prof. Yasutaka Imai Saga University (Japan) Secretariat Prof. Yasuyuki Ikegami Saga University (Japan) Prof. Yusaku Kyozuka Kyushu University (Japan) Chairman of Executive Committee 17 19. SPONSORS Alpha Hydraulic Engineering Consultants Co.,Ltd ClassNK Furukawa Electric Co., Ltd. Fuyo Ocean Development & Engineering Co., Ltd. JGC Corporation Kajima Corporation Kokusai Cable Ship Co., Ltd. MODEC, Inc. National Maritime Research Institute Ocean Energy Association - Japan PAL Corporation West Japan Engineering Consultants, Inc. Wind Power Group 18 20. AWTEC 2014 2nd Asian Wave and Tidal Energy Conference 28 July-1 August 2014, Tokyo Big Sight, Japan AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Current Status - Future Direction Allan Davidson Director Asia AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Harsh conditions Close access to sheltered waters Most northerly point on national grid Energy expertise Marine expertise Why Orkney? 19 21. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson 36m public funding Not-for-profit organisation Self-sufficient since 2011 EMEC funding AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson 2014: 10 wave & tidal devices in Orkney EMEC journey 20 22. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson WORLDS FIRST & ONLY accredited, grid connected wave and tidal test laboratory. Independent facility plug & play Hard infrastructure (cables, grid connection, substation) Soft support services (consents, environmental monitoring, data analysis) EMEC facilities AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Orkney Clustering EMEC office and data centre Lyness Pier Copland's Dock Hatston Pier Supply chainHerriot Watt, ICIT Hatston Ind. Units Full scale tidal site Scale tidal site Scale wave siteFull scale wave site 21 23. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Wave test site: Billia Croo AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Tidal test site: Fall of Warness 22 24. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Installability Survivability Reliability Maintainability Operability Cost effectiveness Real-sea testing AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Scale test sites 23 25. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Integrated Environmental Monitoring (Fall of Warness) AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Achievement 24 26. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Latest highlights Oct 2013: International symposium June 2014: Orkney Ocean Energy Day May 2014: Nautricity deployed Mar 2014: Study on subsea cables Feb 2014: MRCF funding for pod Nov 2013: Singapore MoU AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Future Programmes Planning for future berths and array test site Collaborative venturesStudies re integrated sitesEnergy storage systems Guidelines and StandardsR&D projects 25 27. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Beyond device testing, EMEC provides: Assistance for other testing centres Off site performance assessment R&D project involvement Consultancy support International alliances 10+ years experience AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson 20% of UKs electricity from marine energy Local/national industry development Develop technology for export Transition to post-carbon Security of energy supply Job creation Is it worth it? 26 28. AWTEC, Tokyo 2014 www.emec.org.ukAllan Davidson Follow us on: Thank you 27 29. AWTEC 2014 2nd Asian Wave and Tidal Energy Conference 28 July-1 August 2014, Tokyo Big Sight, Japan The Engineering Challenges in Delivering Robust, Cost Effective Technology for an International Tidal Energy Industry C.M. Johnstone* and C.H. Jo# * Energy Systems Research Unit, University of Strathclyde, UK cameron@esru.strath.ac.uk # Ocean Energy and Environmental Fusion Research Center, Inha University, South Korea chjo@inha.ac.kr SUMMARY: Tidal energy technologies currently being deployed are expensive and considered not to be economically viable. The technologies are heavy resulting in high capital cost of plant and installation costs. They contain complex engineering and control systems therefore incurring high operational and maintenance costs. For tidal energy to be commercially acceptable, significant engineering challenges need addressing to reduce weight, complexity to reduce capital and operational costs and reduce installation costs. This paper identifies these challenges and activities being undertaken to address these. Keywords: Tidal energy, tidal turbine, device deployment, economics of tidal energy. Introduction The extraction of energy from tidal flows has the potential to deliver highly valued and predictable renewable energy[1]. Strategic utilisation of the phased time differences that exist in tidal occurrences around coastlines, allow for this resource to be used for firm power delivery and command a higher value in the electricity market[2]. In an effort to realize this potential a number of Countries have introduced policies to stimulate development of a marine renewable industry[3]. These policies have lead to the introduction of research programs to stimulate technology development; capital grant support programs to reduce investment risk in the development and demonstration of prototype technologies; and the introduction of enhanced feed in tariffs with long qualification periods (15- 20 years) to demonstrate sufficient market pull mechanisms to give confidence and provide the necessary return in investment to attract the high risk investment necessary to stimulate this emerging industry. The introduction of these measures has resulted in considerable research and technology development programs being undertaken in Europe, Asia and North America. In an attempt to stimulate the development of an international tidal energy industry, several Governments have also embarked upon infrastructure investment programs which has seen multi-millions of dollars invested to provide supporting infrastructures, engineering and port facilities dedicated to marine renewable and Test Centres dedicated to the testing and demonstration of marine renewable technology Technology Development Framework As a result of these various investment programs over the past 10 years, a plethora of engineering technologies has been developed to harness energy from tidal flows. Some of these have evolved through the Technology Readiness Levels (TRLs) starting as concepts undertaking extensive engineering evaluation before being tested at small scale in controlled laboratory based test tanks, then being prototyped, scaled up and deployed within pre-commercial technology demonstration projects in order to prove energy can be successfully extracted. This has resulted in a small number of different tidal energy converter concepts being demonstrated at a utility scale of 0.5MW 1MW in capacity, the majority of which have been tested and demonstrated at the European Marine Energy Centre (EMEC) in the UK. In an effort to prove reliability, robustness and resilience to the operating environment, the longest operating of these systems has now been operational 28 30. for intermittent periods of time over approximately a 4 year time period. During this time experiences have been gained and lessons learned in the engineering configuration and operation of these systems. These experiences and new understanding have been fed back into the engineering and technology evolution design phase to inform future product development. In undertaking the engineering development and testing, the information provided is also being used to investigate the economics of these technologies; and where potential cost reductions may be attained in addition to cost reductions associated with the scale of economies as you scale up production volume. These Front End Engineering Design (FEED) studies ultimately establish the economic viability of the technology being developed and ultimately inform how investable a technology currently is and/ or may become. Market Entry and Sustainability For a power generation technology to be viable to enter the free/ open electricity market, it needs to be able to supply electricity to the market at a market set wholesale price. At the time of writing the wholesale price for electricity within the UK electricity market is approximately 50/MWh (US $85/MWh). In order for a technology to be investible, it needs to return a profit against the whole sale price of typically a rate of 8% Return on Investment (RoI). In order to achieve this, the technology needs to have been de- risked. This implies the technology is mature and has already demonstrated robustness and durability with proven operational and maintenance (O&M) costs. It is such technologies which set the wholesale price in the free/ open electricity market. As such, it is traditionally large scale thermal power plant which operates in this market and sets the wholesale price. Since such lant is well proven and mature, they typically have a commissioned cost of plant to be less than 1million/ MW ($1.7 million/ MW). New, emerging and unproven generating technologies attempting to enter this market will inherently attract a higher risk cost associated with the investment. Because of this higher risk, it is not uncommon for RoI to be typically greater than 15%. The combination of high capital costs associated with new technologies and a higher RoI associated with high investment risk results in them not being economically viable and failing to attract the necessary investment needed. This results in these new emerging technologies being prevented from entering the market. In order to address this and assist new technologies enter the market, an enhanced feed in tariff is commonly used. This provides an increased financial return in an effort to share the risk associated with the high costs of un-proven technology and attract the necessary investment. To stimulate renewables development both the UK and South Korean Government introduced a similar the Renewable Obligation Certificates (ROCs) and Renewable Portfolio Certificates (RPCs) scheme respectively. Depending on the technology banding this determines the number of ROCs/ RPCs awarded per MWh generated. In the context of marine renewable, the UK Government has introduced a 5 ROCs/ MWh while the Korean overnment have still to set an RPC value for marine renewable. The unique aspect about ROCs/ RPCs is that while they are awarded over typically a 20 year time period, they are market commodities, therefore their values will vary based on supply and demand. Therefore as supply becomes more abundant their value will reduce accordingly. In the UK at the time of writing, the value of a ROC is 45/MWh ($76/MWh). If generating electricity from tidal energy in the UK, the revenue generated from selling electricity into the market would be the wholesale price plus five ROCs, 275/MWh ($467/MWh). Similar enhanced tariffs, specific to stimulating the development of tidal energy have been introduced by the Government of Nova Scotia, Canada with the introduction of their ComFit awards which has a tariff price set at CN $645/MWh (US $590/MWh). This tariff is 29 31. limited to Community focused projects where the largest capacity single generating unit cannot exceed 500 kW and projects range in size from 0.5MW to a few MWs in size. More recently, the Nova Scotia Government introduced a feed in tariff for larger capacity projects, many associated with deployments to take place the FORCE test site, Nova Scotia. These projects have a Development tariff set at CN $530/MWh (US $500/MWh) for the first 16,560MWh dropping to CN $420/ MWh (US $396/MWh) there aft. These encouraging tariffs have been set due to the high costs associated with the delivery of these initial projects. For projects completed in the UK, and supported by UK and European funding programs has seen these large capacity deployments being delivered at costs exceeding US $17million/MW. In order to develop a sustainable tidal energy market, the costs associated with tidal energy deployment will need to be reduced considerably in order to attract the investment necessary to develop and deliver a commercial tidal energy industry[4]. The UKs experiences with the development of offshore wind energy gives an insight into the elasticity of costs for a new power generation technology[5] and highlights what the market will withstand in terms of capital costs for the delivery of projects and the tipping point beyond which projects become uneconomically viable and therefore un investable. With UK project costs for offshore wind beginning to exceed 3million/MW installed (US $5.1million/MW) this is showing signs of a slowdown in investment and development of these more expensive projects. While an enhanced feeding tariff for tidal energy projects will facilitate more expensive project costs to be absorbed, the higher technology risk offsets this increased margin, therefore for tidal energy projects to be financially investable the project costs need to be amortised within a 5 year time period, with a return on investment of 12%. These figures result in tidal energy projects being delivered at costs of 4million/MW installed[6] (US $6.8million/MW). This 4 million/MW is therefore the target figure tidal energy projects need to be delivered against if tidal energy is to become a commercially investible technology. Technology Deployment While there has been a plethora of scale, proof of concept deployments taken place there has been very few commercial scale deployments with device capacity >0.5MW. Those that have been deployed, especially those at single device capacity of 1 MW, have taken to the water with a systems weight in excess of 1000 tons/ MW, as typically identified in Figure 1. Figure 1: Example of a pre-commercial 1 MW tidal turbine. The system weight includes rotor, gearboxes where appropriate, generator, onboard power take off equipment, nacelle components, station keeping/ supporting structure and seabed connection system. With such a heavy mass per MW of capacity deployed, this often results in very high up-front capital costs associated with the manufacture of the plant, due to the high volume of materials used in production and the handling of heavy masses in the manufacturing process. Full scale technology development and demonstration programs which the authors have been associated with or directly involved in have delivered typical costings of worked (fabricated) costs of 30 32. materials range from $3.5/kg for formed concrete delivered/ installed on site to $55/kg magnetic material used in the generator manufacture. In the context of steel, a basic worked (fabricated) cost of $8.5/kg is widely adopted in fabrication costing. In addition to high capital costs, high mass per MW capacity also incurs very high handling and installation costs[7]. Installing 1000 tonnes on the seabed is a considerable engineering challenge at the best of times and an even greater challenge in locations where high tidal currents are flowing. At sites with high tidal flows, the time window where operations can be carried out are very short, potentially limited to 30 minutes, to times when the tidal flow is changing direction. Operations where times for execution is longer than this requires the use of large specialized dynamic positioning vessels, which can hold station against the tidal flow as it begins to run. This increases the onsite operations to a couple of hours, or potentially through the tidal cycle in lower velocity neap tides. When undertaking the installation and deployment of these large pre-commercial systems, this has relied heavily on the use of large specialised marine vessels with dynamic positioning capabilities. These vessels were originally developed for the offshore engineering and oil and gas sectors. An example of such a vessel used in the installation of a large tidal device is shown in Figure 2. Figure 2: Installation vessel North Sea Giant as used for a 1MW tidal turbine installation These specialised vessels operate on a spot pricing market with daily hire charges varying depending on market demands. This demand is influenced by the rate of development activity in the oil and gas sector. When there is a high demand from the oil and gas sector, such vessels will cost in excess of 200,000/day (US $340,000/day) hire costs, excluding fueling costs and port duties. Therefore, the daily hire charge can easily exceed 300,000/day (US $510,000/day). When hiring a vessel you have to include mobilisation time, operational time and standby time if the weather prevents the vessel from operating. By the time these costs are fully accounted, the total cost for hiring a specialised vessel to undertake such an installation can easily exceed 1million (US $1.7million). If the installation and recovery is dependent on utilising such specialised vessels, this results in high installation, and operational and maintenance costs being encountered which can further jeopardise the financial viability of tidal energy projects. The Engineering Challenge If a commercially viable international tidal energy industry is to be delivered, there has to be considerable engineering breakthroughs which reduces both the capital costs of tidal energy technology and the associated installation and operational and maintenance costs[8]. Engineering for weight reduction is a key factor to reducing the costs of tidal energy. Using the basic material cost of worked steel, the material cost alone associated with the 1000 tonnes/MW means the material costs alone exceeds the target price for tidal energy to be cost acceptable. Without taking mass out of tidal technology it is going to be a major engineering and financial challenge to make tidal energy cost effective. Instead of deploying tidal energy technology at 1000 tonnes/MW, a realistic target figure for engineers to work against could be a value closer to 100 tonnes/MW. Reducing weight saves on the quantities of materials needed and hence reduces the cost of 31 33. manufacture. Additional substantive cost reductions are also attained in transportation and handling. Reducing the transportation and handling weight to manageable sizes allows for standard road transport to be used in delivery of product to site and small (substantively cheaper) cranes to be used in handling and loading. This contributes to a substantive saving being attained not only in CapEx but also in OpEx. Weight reductions are being achieved through the use of lower density composite materials in place of high density steel based materials. Not only does this save weight in air, it results in these components becoming virtually neutrally buoyant in water. This makes in-sea handling much easier and safer. This is already being realised through the greater use of GFRP and Carbon Fibre in rotor blades and nacelle components and composite ropes in place of wire ropes in mooring systems. In the context of GFRP and composite fibre ropes, this can provide considerable capital savings together with large weight reductions. Engineering new station keeping solutions can make a considerable saving on both the plant costs and installation costs. The use of large rigid steel structures on the seabed on which the tidal technology is supported results in a few hundred tonnes of steel having to be fabricated at an expensive cost. Transportation and installation onto the seabed also becomes a very challenging engineering task. This requires the commissioning of heavy lifting equipment and the use of an a very large, expensive installation vessel which has a high lifting capacity, as shown in figure 3. The development of tensioned and catenary mooring systems[9] using steel or fibre ropes has been undertaken for surface floating or mid water column tidal energy convertors. In these systems, the capital costs for the hardware are considerably less, potentially costing 15% of an equivalent rigid steel structure. The size and capabilities of the vessels required for the installation of a flexible mooring system are also considerably less. Figure 3: The use of Excalibre heavy lifting barge for the installation of a tidal turbine supporting structure. Typically a 20m multipurpose marine engineering support vessel is used with a daily hire charge of an order of magnitude less, a few $1,000/day as opposed to a few $100,000/day. Figure 4 shows the installation of a tensioned mooring system for a mid-water column mounted tidal turbine at the EMEC test site, Orkney UK. Engineering to reduce system complexity can make a considerable reduction to the cost of the plant being installed and reduce the operational and maintenance costs. First generation tidal technologies typically include pitch control systems to regulate power capture and facilitate generation on the ebb and flood tides since the devices dont yaw with the change in direction. These pitch control systems need to be substantively engineered since they experience and have to operate in high thrust load conditions. Figure 4: Installation of Nautricitys hydro- buoy tensioned mooring system 32 34. The performance of tidal rotors operating in a relatively low velocity, high density fluid results in the primary drive system from the rotor rotating slowly but with very high torque. To compensate for this, a multi-stage gearbox is used to transfer this low rational speed, high torque power output to a higher speed suitable for an input shaft to a generator. The multi-stage gearbox is therefore a specialized piece of precision engineering which is inherently very expensive. In regulating and conditioning the electrical power output from the generator a number of tidal turbines have adopted on board power electronic control systems. These are highly sensitive pieces of electronic equipment at a cost of many $100,000s. With all these complex systems being crucial to the operation of the tidal device and installed onboard the tidal energy converter, this introduces greater vulnerability. The consequence of this is typically increased operational maintenance requirements. The greater the number of vulnerable components onboard the tidal energy converter the lower the mean time to failure therefore the greater the likely hood of intervention being required. This increases the maintenance costs of the turbine and depending on the type of vessel required for the intervention, can become very expensive. A number of next generation tidal devices are being engineered so that these systems are no longer required. The use of a direct drive generator eliminates the need for a gearbox; and purposefully designing yawing capabilities within the station keeping system allows for fixed pitch blades to be used, eliminating the need for a pitch control system, to date often been the root cause of rotor failure. Next generation engineering is being actively applied in developing, proving and de-risking new concepts to tidal energy capture. These technologies actively address the reduction of tidal energy plant capital costs and are referred to as next generation tidal energy technologies. Next generation tidal technologies use the natural resulting forces to balance of reactive loads on the structure. Neutralisation of these reactive loads enables lower cost, flexible, cable based mooring systems to be utilised instead of very large, rigid steel monopile structures. The cable system is either held to the sea- bed via a gravity base containing the appropriate mass or a framework pinned to the seabed with sufficiently large pins sized for the capacity of device being deployed and the sea conditions and wave exposure the site is exposed to. An example of a next generation tidal technology is shown in figure 5, Scotrenewables SRT tidal energy converter. This has been prototyped, deployed and undergoing testing at the EMEC test site, Orkney, UK. Figure 5: ScotRenewables SRT tidal energy converter. The twin counter-rotating rotors suspended from the floating structure facilitates neutralization of the reactive prop-walk on the floating supporting structure. This allows for a cable based mooring system to be employed for the station keeping system. Another next generation technology being demonstrated at full scale, pre-commercial applications is Nautricitys CoRMaT tidal technology[10], as shown in figure 6. This uses dual axial, fixed pitched, contra- rotating rotors directly driving a contra- rotating permanent magnet generator. This is a mid water column device which is held on station by a tensioned mooring system. 33 35. Figure 6: Nautricitys CoRMaT tidal technology being deployed These next generation technologies are being deployed at weights less than 100 tonnes/MW, therefore experience lower capital costs and lower installation costs. Engineering development still needed to deliver a commercial tidal energy industry include new innovation in the inter- connection of multiple devices. As we move forward towards the deployment of initial arrays, these initial deployments are using dedicated shore landing cables per device installed. The additional costs associated with these dedicated cables result in an additional multi-million dollar expenditure being encountered on these projects. As such these power take-off methods result in these arrays being not financially viable. New cost effective solutions to multiple device-device inter connection is therefore needed to deliver a commercial tidal energy industry. The experiences gained in executing these single device testing programs is providing highly valued knowledge and understanding on both the technical challenges needing to be addressed; and economics of the construction, installation, commissioning and operation. This new knowledge is being fed back into engineering development programs to inform where and how technology can be evolved to reduce costs not only in the capital cost of plant but also the installation and operations of devices. Copyright The copyright of Abstracts and Proceedings belongs to the authors. The Grand RE2014 Organizing Committee has a right to publish Abstract books and proceedings for this conference. References [1] Quantification of exploitable tidal energy resources in UK, npower juice report, July 2007 [2] J.A. Clarke, A.D. Grant and C.M. Johnstone, 'Output characteristics of tidal current power stations during spring and neap cycles', Proc. 8th World Renewable Energy Congress '04, Denver, Colorado, 29 Aug - 3 Sept, 2004. [3] Ocean Energy Systems Implementing Agreement: An International Collaborative Programme. IEA-OES. 2008 [4] Electricity Generation Costs and Investment Decisions: a Review, UK Energy Research Centre, February 2007 [5] The Economics of Wind Energy, The European Wind Energy Association, March 2009) [6] C.M. Johnstone, D. Pratt, J.A. Clarke and A.D. Grant A techno-economic analysis of tidal energy technology Renewable Energy an International Journal Vol. 49, p101-106, January 2013, UK, ISSN 0960-1481 [7] Capital, operating and maintenance costs, The Carbon Trust at http://www.carbontrust.co.uk/SiteCollectionDo cuments/Various/Emerging%20technologies/T echnology%20Directory/Marine/cost%20of%2 0energy/Capital,%20operating%20and%20mai ntenance%20costs.pdf [8] Future Marine Energy, Results of the Marine Energy Challenge: Cost competitiveness and growth of wave and tidal stream energy, The Carbon Trust 2006 [9] J.A. Clarke, G Connor, A.D. Grant, C.M. Johnstone and S Ordonez-Sanchez Contra- rotating Marine Turbines: Single Point Tethered Floating System Stability and Performance Proceedings of the 8th European Wave and Tidal Energy Conference, Uppsala, Sweden, September 2009. [10] J.A. Clarke, G Connor, A D Grant, C M Johnstone and S Ordonez-Sanchez A Contra- rotating Marine Current Turbine on a Flexible Mooring: Development of a Scaled Prototype Proc. 2 nd International Conference on Ocean Energy 2008, Brest, France, October 2008. 34 36. AWTEC 2014 2nd Asian Wave and Tidal Energy Conference 28 July-1 August 2014, Tokyo Big Sight, Japan 35 37. 36 38. 37 39. 38 40. 39 41. 40 42. 41 43. 42 44. 43 45. 44 46. 45 47. 46 48. 47 49. 48 50. 49 51. 50 52. 51 53. 52 54. 53 55. 54 56. 55 57. 56 58. 57 59. AWTEC 2014 2nd Asian Wave and Tidal Energy Conference 28 July-1 August 2014, Tokyo Big Sight, Japan THE LATEST PROGRESS OF WAVE ENERGY IN CHINAAND THE ANALYSIS OF CONVERSION EFFICIENCY CONSIDERING PTO DAMPING Hongda Shi1 , Feifei Cao1 and Na Qu1 1 Ocean University of China, Qingdao, 266100 China Wave energy conversions are widely invented and developed in China; the key factors of these devices are safety and efficiency. The paper gives the latest techniques of wave energy devices investigated in China, introduces their working principles and performances briefly. To design a wave device, the conversion efficiency should be estimated, the paper gives a method of such analysis considering the Power Take-off (PTO), which is an important step of achieving the Wave-to-Wire simulation. Keywords: wave energy, current status, conversion efficiency, PTO INTRODUCTION Wave energy, as one of the most promising marine energies, has received considerable attention for generating electricity. It is estimated that the theoretical mean power of wave energy resource along the coastline of China is about 12.85GW, with the majority distribution in Taiwan, Zhejiang, Guangzhou, Fujian and Shandong Provinces. The research on extracting energy from wave started in the late 1970s in China. With the increasing financial and policy supports from the central government, wave energy conversions and relevant technology have been widely invented and developed since 2010, when the special funding for marine renewable energies was first established. The number of patents about wave energy conversion has been grown dramatically over the past four years, and above 300 patents were newly published only in last year. In terms of the key factors in a WEC device design, this paper is organized in two parts. The first part illustrates some demonstration devices in China including their working principles and performances. The other part describes a method of analyzing extracting efficiency considering the power take-off system. TECHNOLOGICAL PROGRESS Wave energy is mainly used to generate electricity in China. According to the working principle, Falco (2010) classified wave energy converters into three categories: oscillating water column (OWC), overtopping converters and oscillating body systems (which is also called heaving buoy system recently). The progress of wave energy conversion technology in China is discussed in these three types. The work includes investigating some representative devices and giving a brief introduction of their working principles, main dimensions, technical parameters and power output. OWC In the preliminary stage of technological R&D, (before 2000), the research interest was mainly focused on OWC. From 1980 to 2001, Guangzhou Institute of Energy Conversion (GIEC) constructed three onshore OWC type wave power plants successively, with the capacities of 3kW, 20kW and 100kW respectively. As a demonstration project, the 100kW prototype was connected to the power grid. But in general, the conversion efficiencies of these OWC devices were relatively low, and the output was unstable. Fig. 1. 100kW OWC device developed by GIEC Oscillating body systems In comparison with European countries, wave energy resource in China has the characteristics of lower power density, shorter wave period, and smaller wave height. Therefore, since 2000 (Chinas 10th Five-Year Plan), several types of oscillating body systems have been developed funded by National S&T program and SOA Special Funds. National Ocean Technology Center (NOTC) set up a series of 8kW, 30kW and 100kW pendulum type WECs in 1995, 2000 and 2011 respectively. Driven by waves, the pendulum flap swings back and forth to power a hydraulic pump and generator. Similarly, a 5kW inverse pendulum WEC with hydraulic PTO was developed by Zhejiang University in 2010. 58 60. Fig. 2. 30 kW pendulum WEC developed by NOTC From 2009, GIEC began the R&D on the floating nodding-duck, which is on the basis of well-known Salters Duck. The sea trials of 10kW and 100kW nodding-Duck were conducted in 2011 and 2013. Furthermore, GIEC improved the design of Duck and developed a new device named Sharp Eagle in 2012, which has the better performances on both capturing wave energy and resisting typhoon. The capacity was 20kW including 10kW hydraulic PTO system and 10kW linear electrical generator. Fig. 3. 100 kW nodding duck developed by GIEC Fig. 4. 100 kW Eagle developed by GIEC Another technology that has been developing rapidly is point absorber WEC. In 2006, the first 50kW onshore oscillating buoy WEC was built by GIEC. The PTO system includes pressure-maintain storage, which converts unstable wave energy into stable hydraulic energy. This mechanical interface with pumps, gas accumulators and hydraulic motors is applied widely in point absorber devices, such as the single heaving buoy prototype (rated power 120kW) built by Shandong University in 2012 and the combined oscillating buoys WEC (rated power 10kW) developed by Ocean University of China (OUC). A 100kW offshore prototype of combined oscillating buoys WEC is supposed to be constructed in 2015. In addition to hydraulic PTO, GIEC also developed a 20kW single oscillating body device directly driving a linear generator in 2012. Fig. 5. 10kW combined oscillating buoys developed by OUC Overtopping converters The work on overtopping converters is not as much as oscillating body systems in China. OUC took the research on a 10kW floating disk-like overtopping WEC supported by National 863 Program from 2009 to 2011. Fig. 6. 10 kW disk-like WEC developed by OUC CONVERSION EFFICIENCY According to the WECs discussed above with the exception of linear electrical generation, the process of taking out electrical energy from waves, in general, can be divided into three phases: transforming energy from incident waves into reciprocation of absorption systems, converting the wave induced motions into a one-directional motion of the mechanical interfaces (like air turbines, low-head hydraulic turbines and hydraulic motors), and generating electric power. These stages are defined as primary, secondary tertiary conversion stage. To design a wave device, the conversion efficiency of the 59 61. three stages should be estimated in advance. Here we focus the efficiency on the primary stage. It is obvious that the high pressure in the hydraulic system restricts the oscillation of buoys to some extent. Incident wave conditions, as well as the PTO damping effect should be both considered when design an absorber. Establishing coordinate as following figure. Fig. 7. Diagram of the Wave and buoy Say that ( ) sin( )t A kx t is the wave surface, then in the vertical axis of the buoy, ( ) sint A t (1) If the vertical distance of the buoy caused by wave is h(t), and the hydraulic resistance is ( )dh t C dt , then we have: 0 2 2 0 ( ) ( ) [ ( ) ( )] ( ) ( ) [ ( ) ( ) ] ( )m z h t h d h t m gS t h t dt d dh t dh t C S t h t h w C dt dt dt (2) Here, the first item on right side of the equation is buoyancy caused by the movements of wave and buoy. The second item, which is the dynamic force, is proportional to the acceleration of water particle upon the movement of the buoy, Cm is the inertia force parameter, which is defined in Morison equation. The third item, which is proportional to the velocity of buoy, is linear hydraulic damping, PTO. In the potential flow and linear wave theories, w z (3) Where: Ag ekz cos t (4) w zh(t) h0 A ek[h(t) h0 ] cos t (5) 0 0 0 [ ( ) ] ( ) [ ( ) ]2 ( ) cos sin k h t h z h t h k h t h d dh t w A ke t dt dt A e t (6) (7) d dt w zh(t) h0 A k dh(t) dt cos t A 2 sin t (8) (9) (10) (11) 2 2 2 2 0 2 ( ) [ ( ) ( )] ( ) ( ) ( sin )m d h t m gS t h t dt d h t dh t C Sh A t C dt dt (12) 2 0 2 2 0 ( ) ( ) ( ) ( ) ( )sin m m d h t dh t m C Sh C gSh t dt dt SA C h g t (13) The solution of the above equation is: 2 ' 1 2( ) ( cos ' sin ' ) cos sin C t m h t e C t C t a t b t (14) Where: m' mCm Sh0 (15) ' 4 gSm' C2 2m' (16) a SAC (g Cmh0 2 ) ( gS m' 2 )2 C2 2 (17) b SA(g Cmh0 2 )(m' 2 gS) ( gS m' 2 )2 C2 2 (18) If h(t)t0 , dh(t) dt t0 0, then: 60 62. C1 a SAC (Cmh0 2 g) ( gS m' 2 )2 C2 2 (19) 2 1 2 ' ' ' C C C b m (20) The existing of C in the expression of a, b, C1, and C2 stands for the effect of hydraulic power take-off. The figure below shows the movement of the heaving buoy under the wave height of 1m, period of 6sec, and with the diameter of 3m and weight of 2t. It is obvious that the amplitude of the vertical movement is reduced due to the PTO, but the period is still near the wave period. Fig. 8. The movement of the heaving buoy If the efficiency of the device is the function of C, we could understand that when the buoy moves with the velocity which is the same as that of the water particles of the incident waves, while C=0, PTO is 0, on the other hand, when the buoy keeps unmoved, while C=, PTO is 0. So, there must exist a certain C between C=0 and C=, that makes the PTO efficiency the maximum value. CONCLUSIONS The utilization of wave energy in China is developing fast. But the related techniques remain to be developed in the following aspects: The design parameters of absorption system need to be further optimized to reduce the damping effect and improve the efficiency of the primary conversion. As an essential part of WECs, PTOs working mechanism and control method are to be made breakthrough for greater reliability and efficiency. Considering PTO damping, the heaving buoys movement is reduced due to the hydraulic resistance, and the maximum of the efficiency is related to certain C. Acknowledgments This research is financially supported by National High Technology Research and Development Program(863 Program) of China (Grant No.2012AA052601). References [1] Antnio F. de O. Falco, Wave energy utilization: A review of the technologies, Renewable Energy. 14, 2010, pp.889-918. [2] Chuankun Wang, Weiyong Shi, The ocean resources and reserves evaluation in China, 1st national symposium on ocean energy in Hangzhou. 2008, pp.169179. [3] Dahai Zhang, Wei Li, Yonggang Lin, Wave energy in China: current status and perspectives, Renewable Energy. 34, 2009, pp.20892092. [4] Hongda Shi, Zhe Ma, Exploiting Methods of Comprehensive Development of Ocean Energy for Chinese Islands Taking Zhaitang Island for Example, International Conference on Remote Sensing, Environment and Transportation Engineering. 2011, pp.2171-2173. [5] Hongda Shi, Dong Liu, Zhen Liu, Calculation of the Motion Response of a novel wave energy convertor, Journal of Ocean University of China. 41(10), 2011, pp.111-116. [6] Kester G, Clym S W, Quantifying the global wave power resource, Renewable Energy. 44, 2012, pp.296-304. [7] Shujie W, Dong Li, et al., An overview of ocean renewable energy in China, Renewable and Sustainable Energy Reviews. 15, 2011, pp.91111. [8] Waters R, Stalberg M, et al., Experimental results from sea trials of an offshore wave energy system. Applied Physics Letters. 90(3), 2007, pp.90-93. 61 63. AWTEC 2014 2nd Asian Wave and Tidal Energy Conference 28 July-1 August 2014, Tokyo Big Sight, Japan 62 64. 63 65. 64 66. 65 67. 66 68. 67 69. 68 70. 69 71. 70 72. 71 73. 72 74. 73 75. 74 76. 75 77. 76 78. AWTEC 2014 2nd Asian Wave and Tidal Energy Conference 28 July-1 August 2014, Tokyo Big Sight, Japan CHARACTERIZATION OF THE TIDAL CURRENT RESOURCE IN TASMANIA Rahman Rahimi1 , Irene Penesis1 , Mark Hemer2 , Luciano Mason1 , Giles Thomas1 1 Australian Maritime College, University of Tasmania, Launceston, TAS, Australia 2 CSIRO Marine and Atmospheric Research, Hobart, TAS, Australia The tidal current power potential along the coast of Tasmania Australia is evaluated based on numerical hydrodynamic modeling using the flexible mesh version of MIKE 21. Model results are validated against measured data from Australian Tide Table constituents, the Bureau of Meteorology and CSIRO. Model results indicate good agreement with measured data, identifying the Banks Strait as a site with the highest potential. A higher resolution model was developed utilizing the results of the local model as its boundary conditions. The locations in Tasmania with the largest mean tidal stream power density are identified and their characteristics are presented here. Keywords: offshore renewable energy, tidal current energy, resource assessment, numerical modeling, Tasmania INTRODUCTION There is a growing expectation that the energy created by the dynamics of the ocean environment such as waves and tidal currents, will be able to make a real and measurable contribution to the renewable energy agenda over the next 10 years and beyond, both nationally and globally. However, an improved understanding of the energy potential available from local marine renewable energy resources is essential. The global scale resource assessment for tidal energy has already been conducted. These well documented studies show significant potential around the world, however, comprehensive regional assessments with greater details are needed for any region of interest. For this purpose numerous studies on tidal and wave energy in European coastal areas and North America have been conducted over the last decade. The rapid development of tidal stream technology is also demonstrated by the many promising device types at different stages of development known to EMEC among which the SeaGen tidal energy turbine stands out as the first tidal device to have passed the UK Governments operating performance criteria [1]. Australia has a set of locations with relatively strong tidal currents (median speed in the neighborhood of 1m/s), including North East Tasmania, King Sound in Western Australia, Darwin in the Northern Territory, and Cape York in Queensland [2], see Fig. 1. Tasmania is Australias island state with the fifth longest coastline in the country. Tasmania lies between 39.5 and 43.5o S. Bass Strait is an ocean region which separates the mainland from Tasmania. This strait which is a shallow sea with mean depth of approximately 60m is of paramount economic importance to Australia. Tides in this area are mainly semi-diurnal with a form factor, F2.5 ms-1 ) have been recorded at the south-west and south-east ends of the strait (http://www.tidetech.org). Harries et al. [3] stated that tidal currents for the area around Bass Strait islands between mainland Australia and Tasmania are in the range of 100140 W/m2 . Fig. 1. Average tidal current power CSIRO, Ocean Renewable Energy 2015-2050 Griffin et al. [2] determined few regions in Australia where tidal power is technically extractable among which the area between Flinders Island and the rest of Tasmania (called Banks Strait) is noted. Ocean renewable energy: 2015-2050 [8] also mentions that an 8TWh/yr estimate exists for a King Sound (Kimberley, Western Australia) barrage scheme and 0.13TWh/yr for a Banks Strait (Tasmania) tidal stream project. This study [8] states that due to coarse resolution of the computational grid which is about 9km, some narrow straits in the North East of Tasmania with high current velocity are not correctly assessed and mapped. The finest resolution model which was constructed by CSIRO [8] showed the current tidal speed in Banks Strait can reach 2.6m/s. According to National Tidal Facility model, the time averaged power density would be around (Fig 1). Using the characteristics of SeaGen dual-16m-diameter Ocean current turbine as a proxy device, the power output would be about 500kW. 77 79. The review of previous work clearly highlights the need for tidal current energy atlas information to be available for coastal regions. The aim of this study is therefore to develop a methodology for refining macro-scale tidal data into localized information that can be used by Marine Renewable Energy device developers or relevant authorities, to identify suitable deployment locations in coastal regions. The field site that has been examined in this study is coastal regions of Tasmania which has provided an interesting practical perspective in terms of tidal and wave energy resources in previous works [8-10]. For the purpose of this project, the initial stage consists of site screening, in regional scale, Tasmania entirely to ensure capture of all potential sites. Having identified the most promising locations around Tasmania those specific areas will become the focus for more detailed assessments. For detailed modeling purposes, the coast of Tasmania is separated into two subdomains; the North East and North West. The first section of this paper will explain the approach and numerical hydrodynamic model used. Results will then be presented, followed by a detailed discussion of findings and conclusion. METHODOLOGY Numerical modeling of tidal currents For the regional assessment Fig 2, a model was built in the MIKE21 Flow Model FM which is a general numerical modeling system for the simulation of water levels and flows in estuaries, bays and coastal areas. The hydrodynamic model in the MIKE21 Flow Model FM is based on a flexible mesh approach and it has been developed for applications within oceanographic, coastal estuarine environments. The model is based on the solution of the three-dimensional incompressible Reynolds Averaged Navier-Stokes equations, subject to the assumptions of Boussinesq and of hydrostatic pressure [11]. This module is also used to model the small area of Banks Strait for more detailed hydrodynamic characteristics of the tidal stream in this area. For the hydrodynamic modeling of the area (Fig. 2), the computational mesh sizes range from 4800 m2 nearshore to approximately 5 km2 offshore and is in accordance with the site assessment procedure defined by the European Marine Energy Centre Ltd (EMEC) [12]. For each computational domain, the model was run to simulate 6 months starting from the arbitrarily selected date January 1st 2012, with the first 18 hours used for buildup. This provided a sufficiently long record for analysis of the tidal constituents. Computational mesh and bathymetry The high resolution shoreline data from National Oceanic and Atmospheric (NOAA) and the digital sounding data from Australian Bathymetry and Topography [13] are used as the coastline boundary and the bathymetry of the computational grids respectively. For the Banks Strait model, the newly published multi-beam 50m bathymetry data by GA is used. However, these data of Multi-beam Dataset of Australia 2012 only cover small areas and does not cover whole area of interest, however it has been used wherever possible. Boundary condition data The tidal forcing is provided from the tidal database created based on the data from the Earth & Space Research (ESR). ESR provides a tidal package for accessing the harmonic constituents for the ESR/OSU family of tide models, and for making predictions of tide height and currents [14]. The eight major tidal harmonics M2, S2, N2, K2, K1, O1, P1, and Q1 for water levels are extracted from the tidal database and applied at the open boundary of the computational grid as water level time series. Some of these constituents are small compared to M2 but were retained in order to realistically assess the model accuracy against tide and current observations, as in many situations the nonlinear interaction between the constituents are important. Fig. 2. Bathymetry and extent of regional assessenment grid model. Also shown are locations of standard ports used for validation phase (+) and CSIRO current meter instruments locations (*, for the year 1991) Wind (AF) In this study we have conducted a set of comparison tests with actual recorded field survey data which includes both tide and meteorological effects. Atmospheric forcing data (pressure and wind components) were obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) global atmospheric reanalysis (ERA-Interim) [15]. The meteorological fields which are available every 6 hours and have a resolution of 0.125o are used to allow a direct comparison between model and data. 78 80. Table 1 Nine tidal stations that provide harmonic constituents of tidal elevation (Australian National Tides Tables 2012) Port Number Port Name Geographical Position Average Depth (m) 61250 Recherche Bay 43o 33 S, 146o 54 E 2 61220 Hobart 42o 53 S, 147o 20 E 15.57 61155 Coles bay 42o 8 S, 148o 17 E 2 61305 Cape Sorrel 42o 9 S, 145o 2 E 103.61 60835 Seal Bay 40o 8 S, 143o 56 E 5.5 61090 Lady Barron 40o 13 S, 148o 15 E 2 60900 Stanley 40o 46 S, 145o 18 E 9.97 61170 Spring Bay 42o 33 S, 147o 56 E 2.52 60910 Burnie 41o 3 S, 145o 57 E 16.95 Direct Gravitational Tides (DGT) The tidal potential is a force, generated by the variations in gravity due to the relative motion of the earth, the moon and the sun. Wijerante et al. [3] concluded that direct gravitational tidal forcing must be included in numerical models of Bass Strait to better represent the tidal current characteristics. This forcing can be included in the model through tidal potential term in the MIKE 21 FM tools. This forcing acts throughout the computational domain as a direct gravitational forcing and has been in these tests to evaluate its effects on the model accuracy. VALIDATION OF MODEL RESULTS The numerical model was validated against the best available tidal level and flow field data. The calibration parameters were bed resistance and horizontal kinematic eddy viscosity for which many different values were tested. The correlation coefficients between observed and computed time series of surface elevation and current velocity were used to obtain the best model calibration. Surface elevation EMEC [1