Offshore BOS variables for statistical analysis

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seyong.kim
Offshore BOS variables for statistical analysis

Hello, I have some question regarding offshore balance of system variables for statistical analysis as listed below.

1. Are offshore BOS variables not available for input to parametric/stochastic analysis?

2. most of offshore BOS variables shows non-relevance to tornado chart output such as levelized costs and total installed costs even with extreme change (up to 100%) of input variables, is this already known problem and any way to fix it?

Regards,
Seyong

Paul Gilman

Dear Seyong,

In short: The wind offshore BOS model is implemented as a script in SAM's user interface that calculates the BOS cost at the top of the System Costs page from the detailed inputs at the bottom of the page. The parametric and stochastic simulations, and tornado chart macro cannot run the script, so it is not possible to use the detailed offshore BOS inputs for those.

1. No. The inputs for the offshore BOS costs are not available for parametric and stochastic simulations. The reason is that when you change the value of those inputs on the System Costs page, you have to click the "Apply BOS Estimate" button to recalculate the value of the "Balance of system cost ($/kW)" input. Clicking the button runs a script that calculates the cost and applies it to the input. The parametric and stochastic simulations cannot run that script, so there is not a way to include the BOS inputs for those.

To run a parametric or stochastic simulation on the BOS cost, you should be able to use the "balance of system cost" input (under "Capital Costs" at the top of the System Costs page), but it looks like we neglected to enable those inputs for parametric and stochastic simulations. I will investigate that and fix that as appropriate -- you can track progress on that issue here: https://github.com/NREL/SAM/issues/92.

2. That's because of the script that I mentioned in my answer to your first question. The tornado chart macro cannot run the offshore BOS cost script to recalculate the BOS cost from the offshore BOS cost model. You should use one of the BOS cost categories that appear under "Wind Farm Costs" in the list of variables for the tornado chart macro.

Best regards,
Paul.

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