Category Archives: Wave energy

MoorDyn, an open-source mooring model

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MoorDyn is a lumped-mass mooring line model designed for easy coupling with other software (i.e. floating platform models). It supports arbitrary line interconnections, clump weights and floats, and different line properties. The model accounts for internal axial stiffness and damping forces, weight and buoyancy forces, hydrodynamic forces from Morison’s equation, and vertical spring-damper forces from contact with the seabed.

The original version is written in C++ and has been successfully coupled with FAST v7 and other tools/models in Matlab and Simulink. A separate Fortran-based version has recently been incorporated into FAST v8 (nwtc.nrel.gov/FAST8). More information and downloads can be found at www.matt-hall.ca/software/moordyn.

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Wave Farm Code – mwave

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Wave energy converters (WECs) will be deployed in groups or “wave farms”. The hydrodynamic interactions between WECs in a wave farm (i.e. how waves that are absorbed, scattered, or radiated by one WEC affect the others) will have siginificant impacts on the overall power performance of the wave farm.

A recently published paper by researchers at The University of Edinburgh titled “A novel method for deriving the diffraction transfer matrix and its application to multi-body interactions in water waves” presents a new method for computing wave farm performance with results from commercial software. Using the theory, WEC array interactions can be computed on the order of 1,000-10,000 times faster than with standard methods.  However, the method presented in the paper is still somewhat complicated to implement, which would make it difficult for others to employ it.

Open source to the rescue! The authors have chosen to share the wave farm code used in the paper for free. The Matlab package that they developed, including examples of WEC array performance, can be found on GitHub:

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The authors chose to release the code to increase the impact of the work. The code is already being used by another researcher at Oregon State University as part of his wave farm design optimization work and is being evaluated for use by the International DTOcean project, which “aims at accelerating the industrial development of ocean energy power generation knowledge, and providing design tools for deploying the first generation of wave and tidal energy converter arrays.”

NNMREC Open Data Project

awec Open Data is here! nnmrec.oregonstate.edu/open-data The US Northwest National Marine Renewable Energy Center is hosting data from physical tests for the marine renewable energy research community. Sharing experimental data is a great way to increase the impact of your research and gain wider recognition for your work. Already there are data sets from Autonomous Wave Energy Converter tests in the OH Hinsdale Wave Lab at Oregon State University and from a University of Washington Micropower Tidal Turbine. Bret Bosma, the project’s founder said this: “The motivation for the site is to allow researchers and developers to be able to share their data to foster collaborations and advance the industry.” Great idea Bret!

Nemoh – Open source BEM

Ladies and Gentleman, the moment you all have been waiting for is here – L’École Centrale De Nantes has released an open source boundary-element method (BEM) code called Nemoh for the computation of linear wave forces on and wave fields around floating bodies, i.e. wave energy converters (WECs). The software is being released under Apache License, Version 2.0.

An analysis with BEM software is the required first step in the design and modeling of a WEC. Commercial BEM codes can cost $25,000 and up. The release of a free and modifiable BEM software package can help a great number of small WEC developers and researchers who can’t afford the commercial version, and it has the potential to develop a community of users who are actively engaged in improving it!

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You can obtain a copy of Nemoh here: http://lheea.ec-nantes.fr/doku.php/emo/nemoh/start?&#nemoh

Free Wave Energy COE Tool

Printenerginet logo JuliaFchozas logo

Open-source offshore renewable energy is really happening. Free tools are being developed, and OpenORE will bring them all together!

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Aalborg University together with Energinet.dk and Julia F. Chozas Consulting Engineer, have released a freely available online spreadsheet to evaluate the Levelised Cost of Energy (LCOE) for wave energy projects. The open-access tool calculates the LCOE based on the power production of a Wave Energy Converter (WEC) at ten locations. Production data may derive from laboratory testing, numerical modelling or from sea trials. The tool has been developed as a transparent and simple model that evaluates WEC’s economic feasibility in a range of locations, while scaling WEC’s features to the selected site.

You can download the tool from Julia’s website:

www.juliafchozas.com/projects/coe-calculation-tool/