WEC-Sim Version 1.2

Version 1.2 of WEC-Sim is now available on GitHub, and there are lots of great updates!

The NREL/SNL team is also implementing a multi-branch approach, allowing users to use the stable ‘master’ branch or the more advanced/under development ‘dev’ branch.

Updates in ‘master’

  • Nonlinear Froude-Krylov hydrodynamics and hydrostatics
  • State space radiation
  • Wave directionality
  • User-defined wave elevation time-series
  • Imports non-dimensionalized BEMIO hydrodynamic data (instead of fully dimensional coefficients)
  • ‘Variant Subsystems’ implemented to improve code stability (instead of if statements)
  • Bug fixes

Updates in ‘dev’:

  • Morison Elements
  • Body2Body Interactions

WEC-Sim (Wave Energy Converter SIMulator) is an open source wave energy converter simulation tool being developed as a joint effort between the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL) with funding from the U.S. Department of Energy’s Wind and Water Power Technologies Office.  The code is developed in MATLAB/SIMULINK using the multi-body dynamics solver SimMechanics. WEC-Sim has the ability to model devices that are comprised of rigid bodies, power-take-off systems, and mooring systems. Simulations are performed in the time-domain by solving the governing WEC equations of motion in 6 degrees-of-freedom as described in the WEC-Sim Theory Manual.

The NREL/SNL team would like to receive feedback on how WEC-Sim can be improved in the future and to facilitate this process a questionnaire has been created.  It is highly encouraged of all users to fill out the questionnaire as soon as possible.  Thank you for your time and please direct any questions about the current release to Nathan Tom, Nathan.tom@nrel.gov.

Open-access Journals

The number of open-access journals and publications is growing rapidly. These publications can be viewed and assessed by a wider audience, allowing for a broader and more rapid spread of the research. Open-access publishing operates in the same manner as a traditional journal,  except that the cost of publishing is covered by the author or a funding body. Once a publication is accepted, it becomes available for free online. A lot of offshore renewable energy research is undertaken by small companies with limited budgets, and just like in the case of open-source software, having free resources can have a huge impact.

But wait, there’s more!

Make Your Own WEC!

Offshore renewable energy should be fun too!  Researchers in Oregon, USA have developed a simple working model of a wave energy converter (a direct drive linear generator) that you can make at home with your kids! Actually, it looks like the kids can make it by themselves:

The device was designed as part of a teaching curriculum. For more, including paper instructions and how to make the project into a full-fledged science experiment, see the article by NNMREC:



The Structural Design of Wave Energy Devices (SDWED) project, led by Aalborg University, has had an amazing output of free software including advanced hydrodynamic models, wave to wire models, and a spectral fatigue model:


Also, at the bottom of that page is a list many other free software products.

“The Structural Design of Wave Energy Devices project (SDWED) 2010-2014 is an international research alliance supported by the Danish Council for Strategic Research. The project is a five-year endeavour to harness the energy potential in wave energy at competitive costs.” (www.sdwed.civil.aau.dk/)

MoorDyn, an open-source mooring model



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.