Progress in Renewable Energies Offshore

Renewable energies offshore are becoming a significant contributor to the total energy produced in some countries and the interest in the subject is increasing worldwide. Various forms of renewable energy are being developed, from which some are at sea. There are some forms of energy that depend on the sea such as wave, tides and OTEC, which are the ones traditionally known as ocean energy but there are others like wind energy that can also be located at sea and thus be subjected to the same environmental conditions. Therefore, this conference is aimed at addressing all forms of renewable energy at sea, expanding from the concept of ocean energies. 

The first International Conference on Renewable Energies Offshore (RENEW2014) was organized at Instituto Superior Tecnico contributing to the exchange of information on the developments and experience obtained in concept development, design and operation of such devices. 

The scope of this second Conference is broad, covering all aspects of the renewable energies offshore activities such as resource assessment; wind energy; wave energy; tidal energy; ocean energy devices; multiuse platforms; PTO design; grid connection; economic assessment; installment and maintenance planning. 

The Conference aims at covering academically oriented papers, although not only from academic audiences, complementing the various existing initiatives that are associated with exhibitions of equipment both of ocean energy and of wind energy. Therefore, the papers have been subjected to a review process on the full papers and we leave here the recognition of the efforts of the various anonymous reviewers and of the Technical Programme Committee, who shared an important part of the review process. 

The final result after the review process of the 180 submitted abstracts are around 103 papers presented in 4 parallel sessions during the 3 days of the conference. The conference included also plenary presentations in the first morning with a number of invited speakers providing overviews of relevant matters in the various areas. 

The contents of the present book are organized in the main subject areas corresponding to the sessions of the Conference and within each group the papers are listed by the alphabetic order of the authors.

• Resource assessment - waves

1. A hindcast study on wave energy variablility and trends in Le Croisic, France M. Goncalves, P. Martinho & C. Guedes Soares
2. On the peak period distributions conditions on significant wave heights in Aqucadoura, Portugal G. Muraleedharan, C. Lucas, D. Martins & C. Guedes Soares 
3. Assessing the wave energy potential in the Mediterranean Sea using WAVEWATCH III D. Pelli, L. Cappietti & H. Oumeraci 
4. Assessing the utility and effectiveness of the IEC standards for wave energy resource characterisation V. Ramos, R. Carballo & J.V. Ringwood
5. Wave energy potential assessment along the west coast of Fuerteventura G. Rodriguez, G. Clarindo & C. Guedes Soares 
6. Wave energy resource assessment from a 12-year hindcast, for Pembrokshire, Wales A.R. Bento, P. Martinho & C. Guedes Soares 
7. Trends in the available wave power at the Portuguese pilot zone D. Silva, P. Martinho & C. Guedes Soares 
8. Development of a numerical modelling tool for combined near field and far field wave transformations using a coupling of potential flow solvers T. Verbrugghe, P. Troch, A. Kortenhaus, V. Stratigaki & A.P. Engsig-Karup

• Resource assessment - tidal 

1. Evaluation of the Agucadoura pilot area as an ocean current turbine site with ROMS modeled ocean current data T.C. Costa, L.T. Pereira, M. Marta-Almeida & C. Guedes Soares 
2. Assessing the importance of including waves in simulations of tidal stream turbine impacts I. Fairley & H. Karunarathna 
3. Exploring the utility and effectiveness of tidal stream energy resource assessment and characterisation standards: A case study V. Ramos, R. Carballo & J.V. Ringwood
4. Tidal energy resource characterisation in the Dover Strait by using VHF radar and ADCP measurements M. Thiebaut & A. Sentchev

• Resource assessment - wind

1. Assessing climate change effect in offshore wind power in the North of Portugal M. Bernardino & C. Guedes Soares 
2. Regional frequency analysis of wind speed on the coast of Portugal R.M. Campos & C. Guedes Soares 
3. A methodology for the power performance assessment of floating offshore wind turbines A. Couto, P.A.P. Justino, J. Silva & A. Estanqueiro 
4. Application of reanalysis data for offshore wind power potential assessment off the west coast of India G. Nagababu, N.K. Naidu, S.S. Kachhwaha & V. Savsani 

• Environmental monitoring

1. Development of an autonomous offshore monitoring system D.B.S. Lopes & H. Sarmento 
2. Evaluation of offshore wind power potential of India by combining satellite and moored buoy data N.K. Naidu, G. Nagababu, S.S. Kachhwaha & V. Savsani 
3. High resolution monitoring for marine renewable energy L. Ren & M. Hartnett 
4. Additional attenuation detection and correction of radar wave within the interior region of offshore wind farm L. Xie, S.W. Wang, X.P. Yan, F. Ma & S. Haugen 

• Wave energy devices

1. Energy capture optimization for an adaptive wave energy converter J.J. Barradas-Berglind, H. Meijer, M. van Rooij, S. Clemente-Pinol, B. Galvan-Garcia, W.A. Prins, A.I. Vakis & B. Jayawardhana
2. Biomimetic marine energy devices in waves and sheared currents K.A. Belibassakis, E.S. Filippas & Th.P. Gerostathis 
3. Systems engineering applied to the development of a wave energy farm D. Bull, J. Roberts, R. Malins, A. Babarit, J. Weber, K. Dykes, R. Costello, B. Kennedy, K. Neilson & C. Bittencourt 
4. Numerical simulation of a single Floating Point Absorber Wave Energy Converter using OpenFOAM© B. Devolder, P. Rauwoens & P. Troch 
5. Revenue optimization for the Ocean Grazer wave energy converter through storage utilization H.T. Dijkstra, J.J. Barradas-Berglind, H. Meijer, M. van Rooij, W.A. Prins, A.I. Vakis & B. Jayawardhana 
6. Numerical and experimental studies of water impact on conical point absorber buoys H. Li, H. -Z. He, S. -H. Yang, J. Zhang, J. Liang & W. Sheng 
7. Study of the influence of design parameters on the structural behavior of a point absorber wave converter using a finite element approach C. Malca, R. Felismina & P. Beirao 
8. Design optimization of a multifunctional wave energy device G. Palma, S.M. Formentin, B. Zanuttigh, P. Contestabile & D. Vicinanza 
9. Wave energy generation with thermo-chemical storage: Getting a uniform injection into the grid M.C. Rodriguez-Hidalgo, A. Lopez, A. de Bonis, P.A. Rodriguez-Aumente & A. Lecuona 
10. Wave dragon -- 'Coldward and Stormward' I. Russell, E. Friis-Madsen & H.-C. Soerensen 
11. Wave Energy converters: Fix- or self-referenced? W. Sheng & T. Lewis 
12. Modelling of the 3-float WEC M4 with nonlinear PTO options and longer bow beam P.K. Stansby, E. Carpintero Moreno & T. Stallard 
13. Performance of the three-float wave energy converter M4 in regular and random waves L. Sun, J. Zang, P.K. Stansby & E. Carpintero Moreno
14. The modelling of a flap type wave energy converter in a time-dependent mild-slope equation model N. Tomey-Bozo, J. Murphy, T. Lewis, P. Troch, A. Babarit & G. Thomas  
15. Hydodynamic analysis and optimization of a wave activated device S. Xu, J.M. Rodrigues & C. Guedes Soares 

• Wave energy devices - OWC

1. Performance of oscillating water column wave energy converters integrated in breakwaters V. Anvesh, D. Karmakar & C. Guedes Soares 
2. The first worldwide application at full-scale of the REWEC3 device in the Port of Civitavecchia: Inital energetic performances F. Arena, A. Romolo, G. Malara, V. Fiamma & V. Laface 
3. Parametric study of blade shape to enhance performance of a turbine used in OWC K. Ezhilsabareesh & A. Samad 
4. Turbine choice and optimization for a shoreline OWC wave energy plant A.F.O. Falcao, J.C.C. Henriques & L.M.C. Gato 
5. A CFD analysis of the wave field in front of a U-OWC breakwater P. Filianoti & L. Gurnari 
6. Mathematical modeling of a non-axisymmetric floating OWC P.A.P. Justino 
7. Site-specific optimization of an OWC wave energy converter in a Mediterranean area I. Simonetti, I. Crema, L. Cappietti, H. El Safti & H. Oumeraci 
8. Integration of breakthrough concepts into the OWC spar buoy B. Teillant, Y. Debruyne, A. Sarmento, R. Gomes, L.M.C. Gato, M. Fontana, M. Philippe & A. Combourieu 

• Wave energy devices - arrays

1. A 3D-BEM coupled-mode method for WEC arrays in variable bathymetry K.A. Belibassakis, Th.P. Gerostathis & G.A. Athanassoulis 
2. Time domain analysis of array interaction and different heading angles for wave energy converter arrays F. Kara 
3. A critical discussion about optimisation approaches for ocean energy array design V. Nava, M.B.R. Topper, P. Ruiz-Minguela, A. de Andres & H. Jeffrey 
4. Influence of a parabolic reflector wall on the sea state in an array of point absorber wave energy converters R.J. van der Wiel, J. Kramer, P.P.D. van der Ven, M.J.A. Borsboom & M.P.C. de Jong

• Wave energy devices - control

1. Control and instrumentation topologies for an integrated wave energy array C.J. Kenny, D. Findlay, I. Lazakis, J. Shek & P.R. Thies
2. Improving seabed cable plough performance for offshore renewable energy S. Robinson, M.J. Brown, A.J. Brennan, M. Cortis, C.E. Augarde & W.M. Coombs 
3. Tuning a linear quadratic regulator for point absorber wave energy converters D. Valerio, P. Beirao, G. Vissio, G. Bracco & G. Mattiazzo 
4. ISWEC control tuning: Lessons learned G. Vissio, G. Bracco, E. Giorcelli, G. Mattiazzo, D. Valerio & P. Beirao 

• Wave energy devices - PTO

1. Optimization of an oil-hydraulic Power Take-Off system based on an adaptable mechanism interface M. Calvario, J.F. Gaspar, A. Sinha & C. Guedes Soares 
2. Best practices for the use of electrical test infrastructures to validate control strategies: A case study in wave energy conversion F.X. Fay, E. Robles, J.C.H. Henriques & M. Marcos 
3. Practical performances of MPC for wave energy converters F. Ferri, A. Tetu & J. Hals 
4. Concept of reciprocating oil-hydraulic cylinders for increased wave power harvesting J.F. Gaspar, A. Sinha, M. Calvario & C. Guedes Soares

• Ocean energy devices

1. Performance assessment for high temperature OTEC plant H.S. Lee, S.T. Lim, J.H. Moon & H.J. Kim 
2. The performance comparison of the OTEC cycles with an ejector J.H. Moon, H.S. Lee, H.J. Kim & J.I. Yoon
3. Conceptual design of a floating plant of fresh water production by using the ocean thermal energy as power source L.R. Nunez Rivas, J.A. Somolinos Sanchez, L. Blay Munoz & M.P. Portilla 
4. Analytical and numerical investigation of a sea water desalination plant with integration of renewable marine energy (Jorf Lasfar OCP Morocco) D. Saifaoui, M. Rouway, M. Nachtane & M. Tarfaoui 

• Tidal energy devices

1. Operation modelling of tidal energy lagoon proposals within the Bristol channel and Severn Estuary A. Angeloudis & R.A. Falconer 
2. Assessing the performance of tidal turbines arrays using an analytical method: Application to the Alderney Race (France) O.A. Lo Brutto, J. Thiebot, S.S. Guillou, H. Gualous & V.T. Nguyen 
3. Load alleviation technology for extending life in tidal turbines A.M. Young, J.R. Farman & R.J. Miller 
4. Experimental investigation of the turbulent flow behind a horizontal axis tidal current turbine C. Del Frate, F. Di Felice, F. Alves Pereira, G.P. Romano, D. Dhome & J.C. Allo 
5. Design and operation of a 1MW four turbine tidal fence F. Heathcote, C.R. Vogel & R.H.J. Willden 
6. Parametric analysis of a tidal current turbine using CFD techniques T. Karthikeyan, K. Ezhilsabareesh, A. Samad, N. Venkatesan & E.J. Avital 
7. Predictions of the dynamic performance of horizontal axis marine current turbines under the effect of different impact scenarios M. Nachtane, M. Tarfaoui, A. El Moumen, M. Ait Mohamed & D. Saifaoui 
8. PD control with buoyancy compensation for automatic emersion maneuvers of first generation TEC J.A. Somolinos Sanchez, M.P. Portilla, M. Espin, L.R. Nunez Rivas, A. Lopez & E. Segura
9. Assessing the turbulence in a tidal estuary and the effect of turbulence on marine current turbine performance M. Thiebaut, A. Sentchev, F.G. Schmitt & T. Le Kien 
10. Numerical modeling with porous media for current field around HAMT array Y. Watanabe, T. Ikoma, K. Masuda & H. Eto 
11. Computational analysis of blockage designed tidal turbine rotors A. Wimshurst & R.H.J. Willden 

• Wind energy devices

1. Pre-Design of a TLP steel-concrete composite substructure for a 6 MW wind turbine as a way to essential cost-reduction F. Adam, U. Ritschel, E. Plumridge & J. Grobmann 
2. Open-sea 1:30 scale tests on a spar-type offshore wind turbine in parked conditions: Progress and future work C. Ruzzo, V. Fiamma, G. Failla, F. Arena, M. Collu & V. Nava 
3. Aero-elastic analysis and classical flutter of a multi-megawatt slender bladed horizontal-axis wind turbine M.A. Sayed, T. Lutz, E. Kramer & F. Borisade 
4. Supervisory system for the automation of model building and simulations with the wind turbine code FAST E. Uzunoglu & C. Guedes Soares 
5. Performance of barge-type floaters for floating wind turbine K.G. Vijay, D. Karmakar, E. Uzunoglu & C. Guedes Soares 
6. Design and automation of a pile test facility for offshore foundations and first experimental results E. Weichhold, F. Dahlhaus, F. Adam, T. Meier & J. Grobmann 
7. Modular jacket offshore wind turbine support structure for the Northern Portuguese coastal zone B. Yeter, Y. Garbatov & C. Guedes Soares 

• Multiuse solutions

1. Experimental and numerical design of a combined wind-wave concept A. Iturrioz, J. Sarmiento, V. Ayllon, J.A. Armesto, A. Jurado, R. Guanche, C. Vidal & I.J. Losada 
2. Energy yield for co-located offshore wind and tidal stream turbines D.R. Lande-Sudall, T. Stallard & P.K. Stansby 
3. Design of a TLP floating structure concept for combined wind and wave energy exploitation T.P. Mazarakos, D.N. Konispoliatis & S.A. Mavrakos 

• Mooring systems

1. Mooring cable simulations with snap load capturing for wave energy applications J. Palm, C. Eskilsson & L. Bergdahl 
2. Experimental testing of mooring for large floating wave energy converters J.B. Thomsen, F. Ferri & J.P. Kofoed 
3. The influence of biofouling on power capture and the fatigue life of mooring lines and power cables used in wave energy converters S.-H. Yang, J.W. Ringsberg & E. Johnson 
4. The dynamic effects of marine growth on a tension moored floating wind turbine C. Wright, J. Murphy & V. Pakrashi 

• Risk and reliability

1. Evaluating a novel approach to reliability decision support for offshore wind turbine installation T. Gintautas & J.D. Sorensen 
2. Fault tree analysis of the failure of floating offshore wind turbines support structures and blade systems J.C. Kang, L.P. Sun & C. Guedes Soares 
3. Reliability assessment of tidal stream energy: Significance for large-scale deployment in the UK F. Khalid, P.R. Thies & L. Johanning 
4. Uncertainty management in risk assessment of offshore energy structures U. Okoro & A. Kolios 
5. Uncertainty associated with the estimation of drag and inertia coefficients of fixed vertical cylinders K. Raed, E. Uzunoglu & C. Guedes Soares 
6. A novel reliability-based simulation tool for offshore renewable technologies G. Rinaldi, L. Johanning, P.R. Thies & R.T. Walker 
7. On the model uncertainty of wave induced responses of a floating semisubmersible wind system E. Uzunoglu & C. Guedes Soares

• Maintenance planning

1. Operations and maintenance planning for community-scale, off-grid wave energy devices A. Gray, D. Findlay & L. Johanning 
2. Towards improved forecasting for offshore wind turbine O&M transfers P.R. Mills, B. Stephen, D. McMillan & I. Lazakis 
3. Development of innovative coatings for marine renewable energy A. Rodriguez, B. Santos, V. Gonzalez de Lena, A. Yedra & C. Manteca
4. Modelling the propagation of underwater acoustic emissions for condition monitoring of marine renewable energy J. Walsh, I. Bashir, P.R. Thies, L. Johanning & Ph. Blondel 

• Economic assessments

1. Enhancing marine energy competitiveness: Economic assessment of a co-located wave-wind energy farm S. Astariz & G. Iglesias 
2. Economic feasibility of floating offshore wave farms in Galicia, Spain L. Castro-Santos & C. Guedes Soares 
3. Preliminary cost assessment of an offshore floating wind farm installation on the Galician coast H. Diaz, J.M. Rodrigues & C. Guedes Soares
4. The economic potential value of offshore wind near Berlengas A. Faria Lopes
5. Mapping economic performance of wave energy C. Frost, D. Findlay, L. Johanning, E. Macpherson & P. Sayer 
6. The potential offshore energy cluster in Portugal A. Pego, M. Marques, R. Salvador, C. Guedes Soares & A. Monteiro 
7. Evaluation of the expected power output of wave energy converters in the north of the Portugueses nearshore D. Silva, E. Rusu & C. Guedes Soares 
8. Capital costs in tidal stream energy projects: A site-specific approach A. Vazquez & G. Iglesias