What do you do, when your input is missing?

Question

Currently I do a LCA for a cup of coffee but i can´t find all needed Inputs for my processes. As an example, i can´t find a coffee filter. In General the question is: What do you do when you can´t find the perfect Inputs for your process?

Answer 1

Hi there! Almost every person doing LCA gets into this situation from time to time. Some possible solutions are:

1. Ask the manufacturer, if he can provide some first hand data
2. Search for values in (peer-reviewed) literature
3. Use a similar process with reduced representativity (e.g. tea filters)

Be aware that point 1 and 2 can be successfull for single impacts like carbon emissions, electricity demand or water use. If you want to only assess GWP or water use, this can eventually help you but not if you want to do more complex LCIAs like ReCiPe or similar.

You have to decide whether the representativity of the used data set is sufficient, so your results are strong enough to meet the target of your study. Therefore doing a uncertainty/sensitivity analysis is strongly recommended.

Good luck!

Answer 2

Hello Schemas,

Schubele has good points. There is also another option, which is of lower data quality, but is still usable when the flow in question is of low relative importance in the LCIA.

If you know the input material, and the production process, you can model the production of the product yourself. You will not know if this is 100% correct without having secondary data to support transport, waste %, and specific energy consumption in production, but you can get close enough that i t wont matter.

That is how i would approach this, from a practical standpoint.

Good luck.