For the ProBas Database, the presence of positive feedback loops has been observed within the product systems derived from both energy and transport processes. These feedback loops yield wrong results when calculating the impacts of affected processes. The positive feedback loop shown in Figure 1. was observed to be present in product systems calculated from transport processes such as ‘Bus-Linie-Diesel-DE-2020-Variante3’. Figure 1. highlights how for the production of both copper (4.08 x 102 kg per 1 kg) and electricity (4.08 x 102 TJ per 1 TJ) more of each product is required than the production of itself yields. The positive feedback loop shown in Figure 2 was observed to be present in product systems calculated from energy processes such as ‘Kohle-KW-DT-BE-2005’ or ‘Gas-KW-GuD-RU-2005’. The two feedback loops showcased here may not be the only ones present in the ProBas Database. For further information about the inputs and outputs of the flows involved in these feedback loops, please view the Appendices section.
Figure 1. Positive feedback loop present in product systems calculated from transport processes in the ProBas Database. Here is has been highlighted that more electricity is needed to produce electricity (4.08 x 102 TJ per 1 TJ) or more copper to produce copper (4.08 x 102 kg per 1 kg).
Figure 2. Positive feedback loop present in product systems calculated from energy processes in the ProBas Database.
Appendix
Appendix 1. Inputs and outputs of ‘Netz-el-DE-Verbund-HS-2005’ as displayed on the Probas webpage (source: https://www.probas.umweltbundesamt.de/php/prozessdetails.php?id={285C60E2-B6A2-484C-8EC0-FDF87DA8A3A6}) and in the openLCA ProBas Database.
Appendix 2. Inputs and outputs of ‘MetallKupfer-DE-primär-2020’ as displayed on the Probas webpage (source: https://www.probas.umweltbundesamt.de/php/prozessdetails.php?id={0A54E43A-373D-43DB-973B-7915BAFA8207}) and in the openLCA ProBas Database.
Appendix 3. Inputs and outputs of ‘FabrikBraunkohle-Brikett-DE-rheinisch-2000’ as displayed on the Probas webpage (source: https://www.probas.umweltbundesamt.de/php/prozessdetails.php?id={0E0B27D3-9043-11D3-B2C8-0080C8941B49}) and in the openLCA ProBas Database.
Appendix 4. Inputs and outputs of ‘Wärme-Process-Zement-Braunkohle (Endenergie)-2000’ as displayed on the Probas webpage (source: https://www.probas.umweltbundesamt.de/php/prozessdetails.php?id={0E0B2BEF-9043-11D3-B2C8-0080C8941B49}) and in the openLCA ProBas Database.
Appendix 5. Inputs and outputs of ‘Steine-ErdenZement-Klinker-DE-2000’ as displayed on the Probas webpage (source: https://www.probas.umweltbundesamt.de/php/prozessdetails.php?id={0E0B2CB9-9043-11D3-B2C8-0080C8941B49}) and in the openLCA ProBas Database.
Appendix 6. Inputs and outputs of ‘Steine-ErdenZement-DE-2000’ as displayed on the Probas webpage (source: https://www.probas.umweltbundesamt.de/php/prozessdetails.php?id={0E0B2CB6-9043-11D3-B2C8-0080C8941B49}) and in the openLCA ProBas Database.
