Hi, sorry to hear the frustration - we have recently looked into this, and several things:
- this is so far (in my knowledge) primarily important for the ecoinvent database, the only database where uncertainty values are contained
- we will modify the new ecoinvent release 3.11 so that the amount without uncertainty will be the same as the point estimate for the probability distribution
- ecoinvent contains some funny uncertainty values which are obviously incorrect, much too high; in openLCA, we do not correct these, thus these can influence the results. To illustrate this, here two plots of ecoinvent exchanges uncertainty, one for the geometric standard deviation, and one for the few thousand normally distributed exchanges, the coefficient of variance, standard deviation devided by mean.
If you have a few processes in your system where the standard deviation / mean is 1E+17 or also 1E+9, or the exponent in the geometric mean is 1000, it is not surprising to get funny simulation results. Pictures for upcoming ecoinvent 3.11 cutoff but this is similar in earlier versions.
-> we think to add an option in openLCA to clean up obviously nonsense distribution values, but want to make users aware of this and not "sugarcoat" and clean up these just while doing the simulation. That is a difference to Brightway then where this clean up is always applied, for the log normal distribution.
