I`ve noticed my Monte Carlo analysis of my models are giving negative results, so I`ve looked back at the models and found that the input processes are also giving negative results, for example inverter production, 0.5kW, cut-off, U (RER) and electricity production, photovoltaic, 570kWp open ground installation, multi-Si, cut-off, U (PT).
For example, within electricity production, photovoltaic, 570kWp open ground installation, multi-Si, cut-off, U (PT) using ReCiPe(H, Midpoint) 2008 the value for GWP100 for 1kWh of electricity is 0.05945 kgCO2eq, which is close to the Ecoinvent website`s value of 0.062657 kgCO2eq.
The Monte Carlo analysis which I am currently re-running is varying from -213 to 67.576 kgCO2eq.
This is a process I have not changed in any way.
I`ve also noticed the lognormal values for uncertainty within Ecoinvent are different to those within OpenLCA, for example, for inverter production, 0.5kW, cut-off, U (RER) the geometric standard deviation of wire drawing, copper is 1.2214, whilst is OpenLCA`s version of Ecoinvent it is 1.1051709180756477. Could this be the source of the issue?
I am using Ecoinvent 3.1 (cut off), to compare with some older models I produced in other software, is this the issue? Does Ecoinvent 3.3. work better?
Anyone on here experienced similar issues?
Edit 1: Now trying Ecoinvent 3.3. and there`s no issue, but I would like to use Ecoinvent 3.1 in order to compare with other work, anyone got any suggestions?
Edit 2: I have exported the electricity production, photovoltaic, 570kWp open ground installation, multi-Si, cut-off, U (PT) from Ecoinvent 3.1 as an ILCD file and then imported it into Ecoinvent 3.2, it appears to be working, and the GWP100 (ReCiPe (H) 2008 Midpoint) is closer within the analysis tab to the Ecoinvent 3.1 value (now 0.06361 kgCO2eq from OpenLCA, with Ecoinvent 3.1 as 0.062657).