Wave farm impact on beach modal state

Abstract The extraction of wave energy by the Wave Energy Converters (WECs) forming a wave farm results in a milder wave climate in its lee, which can have an impact on coastal processes. The objective of this work is to determine whether the beach morphology can be altered by the operation of the wave farm, and if so, to quantify this alteration. For this purpose, we examine how the farm affects the modal state of the beach with reference to a baseline (no farm) scenario. The modal state is defined based on an empirical classification that accounts for wave conditions, tidal regime and sediment size. As a beach typically goes through different modal states, we determine the percentages of time in an average year corresponding to each state in the baseline scenario, and how these percentages are altered by a wave farm as a function of its distance from the coast. This methodology is illustrated through a case study: Perranporth Beach (UK), an area of great potential for wave energy development. High-resolution numerical modelling is used, with two levels of grid refinement. We find that the wave farm has a relevant impact on the modal state of the system, which passes from wave-dominated to tide-dominated during significant periods of time. The sensitivity analysis, involving three cases with the farm at distances of 2 km, 4 km and 6 km from the beach, showed that the farm-to-coast distance plays a major role. Thus, the shift from a wave- to a tide-dominated beach is exacerbated in the case of the wave farm closest to the coastline, with the submarine bar vanishing over long periods of time. We conclude that the presence of the wave farm drastically alters the morphological response of the beach, and that this alteration is strongly dependent on the farm-to-coast distance.

[1]  Q. Zou,et al.  Impacts of a Wave Farm on Waves, Currents and Coastal Morphology in South West England , 2013, Estuaries and Coasts.

[2]  A. Kouzmin,et al.  IT Development: , 1966, Current History.

[3]  Gregorio Iglesias,et al.  Coastal defence through wave farms , 2014 .

[4]  F. Budillon,et al.  Sediment transport and deposition during extreme sea storm events at the Salerno Bay (Tyrrhenian Sea): comparison of field data with numerical model results , 2006 .

[5]  N. Booij,et al.  THE "SWAN" WAVE MODEL FOR SHALLOW WATER , 1997 .

[6]  Justin E. Stopa,et al.  Assessment of wave energy resources in Hawaii , 2011 .

[7]  D. Evans,et al.  Suspended sediment transport in the swash zone of a dissipative beach , 2005 .

[8]  Gregorio Iglesias,et al.  Wave energy and nearshore hot spots: The case of the SE Bay of Biscay , 2010 .

[9]  Gregorio Iglesias,et al.  Wave energy potential in Galicia (NW Spain) , 2009 .

[10]  G. Iglesias,et al.  Wave farm impact on the beach profile: A case study , 2014 .

[11]  Dean L. Millar,et al.  Modelling analysis of the sensitivity of shoreline change to a wave farm , 2007 .

[12]  Gregorio Iglesias,et al.  Wave and offshore wind energy on an island , 2014 .

[13]  Robert G. Dean,et al.  Heuristic Models of Sand Transport in the Surf Zone , 1973 .

[14]  Gregorio Iglesias,et al.  The new wave energy converter WaveCat: Concept and laboratory tests , 2012 .

[15]  Barbara Zanuttigh,et al.  Near-Shore Floating Wave Energy Converters: applications for coastal protection , 2011 .

[16]  Dean L. Millar,et al.  Further analysis of change in nearshore wave climate due to an offshore wave farm: An enhanced case study for the Wave Hub site , 2012 .

[17]  Carlos Guedes Soares,et al.  Numerical evaluation of the wave energy resource along the Atlantic European coast , 2014, Comput. Geosci..

[18]  J. Chick,et al.  European Wave and Tidal Energy Conference , 2009 .

[19]  A. Sarmento,et al.  The impact of wave energy farms in the shoreline wave climate: Portuguese pilot zone case study using Pelamis energy wave devices , 2010 .

[20]  Gregorio Iglesias,et al.  Wave farm impact based on realistic wave-WEC interaction , 2013 .

[21]  A. Castro,et al.  Neural network modelling of planform geometry of headland-bay beaches , 2009 .

[22]  Gerhard Masselink,et al.  The Effect of Tide Range on Beach Morphodynamics and Morphology: A Conceptual Beach Model , 1993 .

[23]  Hans Bernhoff,et al.  Wave energy resources in sheltered sea areas: A case study of the Baltic Sea , 2006 .

[24]  C. Soares,et al.  Assessment of wave energy in the Canary Islands , 2014 .

[25]  Gregorio Iglesias,et al.  Headland-bay beach planform and tidal range: A neural network model , 2009 .

[26]  R. A. Jones,et al.  Simulation of large-scale coastal change using a morphological behaviour model , 1995 .

[27]  Ian L. Turner,et al.  The influence of swash infiltration–exfiltration on beach face sediment transport: onshore or offshore? , 2001 .

[28]  Francisco Taveira-Pinto,et al.  A high resolution geospatial database for wave energy exploitation , 2014 .

[29]  A. Carillo,et al.  Wave energy resource assessment in the Mediterranean, the Italian perspective , 2013 .

[30]  Barbara Zanuttigh,et al.  Beach response to wave energy converter farms acting as coastal defence , 2014 .

[31]  T. Baldock,et al.  Spectral signatures for swash on reflective, intermediate and dissipative beaches , 2014 .

[32]  Gregorio Iglesias,et al.  Wave farm impact: The role of farm-to-coast distance , 2014 .

[33]  Mario Lopez,et al.  Assessing the optimal location for a shoreline wave energy converter , 2014 .

[34]  Gregorio Iglesias,et al.  Wave and offshore wind potential for the island of Tenerife , 2013 .

[35]  H. Fritz,et al.  Wave power potential along the Atlantic coast of the southeastern USA , 2009 .

[36]  Tim Scott,et al.  Temporal observations of rip current circulation on a macro-tidal beach , 2010 .

[37]  P. Russell,et al.  Morphodynamic characteristics and classification of beaches in England and Wales , 2011 .

[38]  Gregorio Iglesias,et al.  A wave farm for an island: Detailed effects on the nearshore wave climate , 2014 .

[39]  G. Iglesias,et al.  Coastal defence using wave farms: The role of farm-to-coast distance , 2015 .

[40]  Gregorio Iglesias,et al.  Choosing the site for the first wave farm in a region: A case study in the Galician Southwest (Spain , 2011 .

[41]  B. Latteux,et al.  Approaches to long-term modelling of coastal morphology : A review , 1993 .

[42]  A. Cornett.  A GLOBAL WAVE ENERGY RESOURCE ASSESSMENT , 2008 .

[43]  Miles O. Hayes,et al.  What is a wave-dominated coast? , 1984 .

[44]  Tim Scott,et al.  Beach Rescue Statistics and their Relation to Nearshore Morphology and Hazards: A Case Study for Southwest England , 2007 .

[45]  A. Baquerizo,et al.  On the development of large-scale cuspate features on a semi-reflective beach: Carchuna beach, Southern Spain , 2003 .

[46]  Barbara Zanuttigh,et al.  Experimental investigation of floating wave energy converters for coastal protection purpose , 2013 .

[47]  Gregorio Iglesias,et al.  Wave energy potential along the Death Coast (Spain) , 2009 .

[48]  G. Iglesias,et al.  Potentials of a hybrid offshore farm for the island of Fuerteventura , 2014 .

[49]  M. Losada,et al.  The influence of shelf-indenting canyons and infralittoral prograding wedges on coastal morphology: The Carchuna system in Southern Spain , 2014 .

[50]  Gerhard Masselink,et al.  Morphodynamic variability of high-energy macrotidal beaches, Cornwall, UK , 2014 .

[51]  L. Wright,et al.  Morphodynamic variability of surf zones and beaches: A synthesis , 1984 .

[52]  R. Paasch,et al.  Characterizing the wave energy resource of the US Pacific Northwest , 2010 .

[53]  Gregorio Iglesias,et al.  Offshore and inshore wave energy assessment: Asturias (N Spain) , 2010 .

[54]  Shunqi Pan,et al.  An investigation of the impacts of climate change on wave energy generation: The Wave Hub, Cornwall, UK , 2011 .

[55]  Pasquale Contestabile,et al.  Wave energy potential in the north-west of Sardinia (Italy) , 2013 .