ProBas+ negative results/ different results for unit and process system

Question

Hi,

I am working with the ProBas+ database in openLCA for my master thesis. Unfortunately I get loads of negative impact results, espacially when I use preset processes from the database like transport with train or process heat. This happens for all LCIA methods.

For example the process "Steine-Erden\Zement-Klinker" for 2010 has a positive impact regarding climate change but for 2000 and 2005 its negative. How is this possible?

Furthermore I noticed that depending on whether I choose unit or system process for a new product system I get different results with the same impact assessement method. How is this possible?

Thanks in advance

Answer 1

Hi Yannik,

it is a bit sad but the ProBas database is not well organised. Calculations in the original data often lead to mis-specified systems, and results for unit processes commonly do not match the system results in ProBas. Plus, I think it is fair to state that flow nomenclature and flow details are not up to date any more ("Staub, unspezifisch"). If you do not have access to another database, use the system processes and build mainly your own foreground system, maybe by updating and modifying unit processes provided in ProBas/ProBas+. For the clinker processes, the system (LCI) process version has quite similar values for e.g. 2005 and 2010.

Best wishes,

Andreas