title: PerAWaT - Implementation of Wave Energy Converters in Spectral Wave Models (WG1 WP2 D2)
Creators: name: Queen’s University Belfast
Publisher: name: ETI
Year: 2011
Subjects: subject: Marine
subject: RENEWABLE ENERGY SOURCES (Ocean Energy)

description: The Performance Assessment of Wave and Tidal Array Systems (PerAWaT) project, launched in October 2009 with £8m of ETI investment.The project delivered validated, commercial software tools capable of significantly reducing the levels of uncertainty associated with predicting the energy yield of major wave and tidal stream energy arrays. It also produced information that will help reduce commercial risk of future large scale wave and tidal array developments.<br><br>This document addresses the practical aspects of the implementation of a wave energy converter representation in a third generation spectral wave model.Section 1: IntroductionScope of the document and the relationship of this document to other deliverables.Summary of the closely related deliverable WG1 WP2 D1, which describes the physical representation of wave energy converters in a third generation spectral wave model, is provided,Acceptance criteria for this deliverableSection 2: Overview of development strategyMethods for achieving the key desirable characteristics of the new software (flexibility, user-friendliness, and reliability)How the software modification will be carried out on four separate key elements successively, and then the integration of these elements that will provide the final software tool. Key elements:representation of a wave energy converter,location of the wave energy converters,input of wave energy converter parameters,output of wave energy converter power capture.The software development tools which will be used for the project are described and the reason for the specific tool choice is explained.The Microsoft VisualStudio program will be used for interactive development of the code, and the Git source code management (or revisioning) software will be used to manage changes to the code.Section 3: Selection of spectral wave modelTwo open source models, SWAN and TOMAWAC, are identified as good candidates and a close comparison of the two models is carried out.The comparison includes an assessment of the physical processes represented in the models and their ease of use and modification.Two test cases are implemented in both models to aid in the comparison.Although the models solve the same equation in a totally different way, it is shown that the results are very similar, and that neither model can be eliminated as a potential candidate based on physical process representation.The final model choice is TOMAWAC, because it was developed at EDF which is associated with the PerAWaT project and support for interpretation of the source code is more readily available.However, both models were deemed suitable for the task, and therefore should there be an unforeseen problem with TOMAWAC, it would be possible to proceed with SWAN.Section 4: Core elements of software toolDescribe seach of the four core elements in detail, and outlines the development process for each of them.New subroutines, and existing subroutines and variables which require modification are identified.Additionally, for each core element the method for verification that the added code is working correctly is described.Section 5: Validation of the SpecWec toolValidation of the representation of wave energy converters in a spectral wave model.Two key parameters which will be addressed during the validation process are identified as wave energy converter density, and wave energy converter performance.Because there is no wave farm data available for the validation process, the spectral representation of wave energy converters will be compared with both the time-domain model WaveFarmer being developed at Garrad Hassan, and the wave tank experimental data which is due to be carried out at Queen’s University Belfast as part of the PerAWaT project.