Calculating negative impact values for processes from the USLCI database?

Question

When running the impact analysis (Recipe Midpoint 2016 (H)) for the process Crude oil, extracted, from the USLCI database; the impacts are all negative, no negative outputs are in the unit process. This occurs when the process is used in a larger system as well as on its own. Is there a known issue with the data or the way openLCA reads it? Attached screenshots.

Answer 1

This issue (having to do with allocation factors in petroleum refining) was resolved with the corrections released as of the USLCI 2020 (Summer Quarter) version. If you use the latest version of USLCI from the Federal LCA Commons, you will also need methods adapted to the Federal Elementary Flow List (FEDEFL), to which the USLCI converted in 2019. The FEDEFL and the FEDEFL-adapted methods are available on the Federal LCA Commons for download and import, e.g., into your openLCA desktop application. Please see the USLCI GitHub Support Content (https://github.com/uslci-admin/uslci-content/wiki) and/or the NREL USLCI Quick Help YouTube video series (https://www.youtube.com/playlist?list=PLmIn8Hncs7bFUOyXZNGXwG4LtdoTfLz6Q) for details on USLCI Database versioning, using FEDEFL-adapted methods, and running calculations on USLCI in openLCA.

Alternatively, you can manually implement relevant corrections from the USLCI Change Log into the Nexus paid-for verison until the updates become available: https://github.com/uslci-admin/uslci-content/blob/dev/docs/release_info/change-log.md.

Comments

I'm still getting the problem

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Are you using the Commons FEDEFL (elementary flow list)-adapted Methods on the most current version of the USLCI Database: https://github.com/uslci-admin/uslci-content/wiki/FEDEFL-Adapted-LCI-&-LCIA-Methods?