Hybrid life cycle assessment (LCA) does not necessarily yield more accurate results than process-based LCA

Yi Yang*, Reinout Heijungs, Miguel Brandão

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review

    104 Downloads (Pure)

    Abstract

    Hybrid life cycle assessment (LCA), through combining input-output (IO) models and process-based LCA for a complete system boundary, is widely recognized as a more accurate approach than process-based LCA with an incomplete system boundary. Without a complete process model for verification, however, the performance of hybrid LCA remains unclear. Here, using a counterexample we show that hybrid LCA does not necessarily provide more accurate results than process-based LCA, simply because the aggregation of heterogeneous processes in IO models may introduce more errors. In so doing, we prove that only when IO-based LCA and process-based LCA have the same level of detail would they yield the same results. Whether hybrid LCA provides more accurate estimates depends on whether the IO model introduced serves as an adequate proxy for the missing products as opposed to if they were estimated by a complete process model. The use of a highly-aggregated IO model runs the risk of overestimation, and could result in a larger relative error than the truncation error resulting from an incomplete process model. Our study seeks to provide a balanced view of hybrid LCA, and our findings offer important insights for future hybrid LCA studies to improve the accuracy and realm of applicability of the approach.

    Original languageEnglish
    Pages (from-to)237-242
    Number of pages6
    JournalJournal of Cleaner Production
    Volume150
    Early online date3 Mar 2017
    DOIs
    Publication statusPublished - 1 May 2017

    Funding

    FundersFunder number
    Horizon 2020 Framework Programme669062

      Keywords

      • Aggregation
      • Hybrid
      • Input-output
      • Life cycle assessment
      • Process
      • System boundary
      • Truncation error

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