O&M Cost Model Used in Wisdem


Before downloading Python and installing WISDEM, I tried to understand the O&M cost model used in WISDEM, but I can’t find a manual or theory behind it on the web. From the presentations, I see that some of the inputs are layout Design and component mass, material properties, and dimensions. While I can guess how this information can affect the initial cost of the project, it is not clear the effect on operating costs, specifically:

  1. How is the component reliability is modeled/estimated?
  2. Is the O&M cost model based on discrete events? Is it replicating the 2008 era Spreadsheet Cost Spreadsheet? (Unless there is a more recent one)
  3. Is there any Optimization happening?
  4. Does WISDEM come up with O&M cost as a bulk for project life or it has a year by year breakdown?

Is there any literature that you can point me to where I can find answers to this.
Thank you very much,

Best regards,


Hello Anton,

Thank you for your question. You are correct that there is not a lot of documentation online, we will hopefully be addressing that in the future, but it is a slow process. To answer your questions:

WISDEM is a steady-state analysis tool, so no fatigue loads are calculated and therefore component reliability is not a current output. We have some ideas about implementing surrogate fatigue models based on steady flow inputs, but no current funding to support that activity.

O&M costs can be estimated using an old regression curve (that is likely outdated for current turbine sizes) in the stand-alone NREL Cost and Scaling Model (CSM):
See line 1522 of https://github.com/WISDEM/WISDEM/blob/master/wisdem/nrelcsm/nrel_csm.py

If not using the CSM, O&M costs can be set as a static user input in the Plant_FinanceSE module:
See “opex_per_kW” input in https://github.com/WISDEM/WISDEM/blob/master/wisdem/plant_financese/plant_finance.py
To answer your question on the units, this is taken as an average annual cost over the project lifetime.

O&M cost modeling has long been a gap in the WISDEM toolset. We have either relied on outdated regressions, user-input values, or 3rd party tools. Fortunately, we are just beginning an O&M model development process that will leverage the discrete event simulation infrastructure in the offshore balance-of-plant cost model, ORBIT (repo: https://github.com/WISDEM/ORBIT and WISDEM integration:https://github.com/WISDEM/WISDEM/tree/master/wisdem/orbit links). It will rely on user-input failure rates.



Thank you very much for such a thorough explanation. This was very helpful.
Best regards,


I am so sorry to bother you, but I want to get some help form here. I am recently beginning using the WISDEM , and I have download Anacoade, and install WISDEM correctly. But I don’t know how to star a case with WISDEM, for excemple it shows this code when I try to run the test.

( by the way I never used Python before) Can you give me some advice ?
Thank you

Best regards


Hi Long Gao,

As for advice with Python, that is probably outside the realm of this forum. If you simply Google “beginner python tutorial”, you will find many helpful online resources and there are many, many good books too.

As for WISDEM, it doesn’t look like the installation was succesfull as you are missing some of the third-party packages. The specific error is for ruamel_yaml, but the full list of dependencies is found here and by following the installation instructions.

Once you have a feel for python, you can work through the WISDEM examples in the documentation to get started.

Good luck!