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I am running montecarlo simulation and the results I get are extremely wide ranges for GWP (kgCO2ep) calculation and CO2(kg):

mean 8675.469313max 38751.33064min -12260.45634

when the results from the normal calculation gives me -350 kgCo2eq

The input and output I inserted are all positive, but the impact assessment transforms CO2 inputs in negative numbers to calculate carbon sequestration of biogenic materials. Is this the reason why I have such variability? Is there a way around it?

Thank you,


in openLCA by (180 points)

1 Answer

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by (64.1k points)
Hi Valeria,

this is an interesting question and I think it covers a problem not really discussed in LCA yet; of course the ranges you obtain depend on the distribution that is specified for the data, but they also depend on the structure of the inventory model. In case of loops, the system can "derail" in a Monte Carlo simulation, e.g. the loops can potentially receive values that make them non-converging, leading to extreme values. This is not incorrect I think from the calculation model, albeit these derailed circles represent non-realistic situations, and thus theoretically we could catch these situations, and show then only the cleaned, "non-derailed" results. Would you prefer this (to all) - and I hope you understand that this is more for future developments then in openLCA.

All the best and thank you again for your question,