My Original Question:

I’ve run into an issue where I would like to provide module costs for electricity to represent T&D and admin costs, so that the total costs in the module (including Fixed and Variable O&M, Capital, and Fuel costs) can be compared with the revenue from tariffs. Ideally, I’d like to specify these T&D and admin costs as a function of output, and LEAP provides a facility for doing so, but I get the attached error message during calculations. The message of course makes sense, but it seems like I was able to make this work before. I developed a work-around by essentially per-calculating output for the relevant scenarios, and using those outputs-by-year as fixed vectors in the calculation of module costs, but that’s not ideal.

Charlie's Response:

On this issue, you’ll need to reference the Previous Year’s (lagged) value of outputs for this to work. You can use the PrevYearValue or Value(xxx, Year-1) functions for this. This isn’t anything new. I know this is not exactly the same thing as what you are trying to do, but in most practical cases it should be near enough.

My Follow-up:

Thanks. Given that output in my area is growing fast, I may put in an additional few percent (multiplying by 1.05) beyond the lagged outputs to account for those differences, but it will certainly be a better method than what I have now. I tried the method you suggested and it worked. I was unable to find the "PrevYearValue" function in the current version of LEAP, but I found and was able to use the "Value(xxx, Year-1)" function.