Developing a roadmap for Inventory Model Description and Revision in Life Cycle Assessment

Life cycle assessment (LCA) results are often used to provide support to decision makers when information is needed about the relative environmental or social impacts of different approaches or product designs. LCA... [ view full abstract ]

Life cycle assessment (LCA) results are often used to provide support to decision makers when information is needed about the relative environmental or social impacts of different approaches or product designs. LCA practitioners face many challenges in their efforts to describe, share, review and revise their inventory models, and to reproduce the models and results of others. Current techniques for LCA authoring limit how authors can communicate details to their readers about the structure of their model and the selection of background data. The use of proxy data is also common, but evaluating the appropriateness of an author's use of proxy data is challenging if the model structure is not clear. Practitioners must also deal with licensing, confidentiality of data, and other issues around data access which impact how a model can be shared.

We report the progress of a discussion group surrounding the description and revision of LCA inventory models, which is part of an ongoing project to develop a "capability roadmap" for LCA. The capability roadmap is meant to guide development throughout the LCA community by prioritizing research and development. The objective of the discussion group is to outline the steps necessary to facilitate LCA model sharing and reproducibility of LCA results among different users, in a way that is independent of the LCA software used to compute the results. The draft roadmap document identifies a number of milestones in three areas:

• formalizing life cycle inventory model description;
• data availability and ready access;
• sustaining and innovating LCA business models.

 Methods and technologies developed under the roadmap should be compatible with existing LCA software packages and services, and should enhance, and not impair, the ability of software and data providers to be financially stable and sustainable.

The problem of model description and revision is distinct from the problem of LCA software and data interoperability, which focuses on accurate exchange of data and metadata for processes and flows but generally omits discussion of how the processes and flows are connected together in a model. Having a more precise delineation between model structure and inventory data would allow LCA models to be subjected to more rigorous inspection, review, and/or analysis of structure or logic, while preserving the privacy of proprietary information. This could help LCA results become more robust and could improve confidence in the results. Having the ability to easily share models would also advance the use of LCA in sustainability research, where it is crucial for researchers to build upon one another's work. In this respect the roadmap is complementary to ongoing efforts within industrial ecology to improve the interoperability and re-usability of models.