Consistent Incorporation of Multiple Background Scenarios Into One Background Database: Proposition of a New Approach

Abstract

When analyzing future impacts of emerging technologies, one has to account for future developments in the background system to ensure temporal consistency between the foreground and background system. This can be achieved by incorporating scenarios into a background database, such as ecoinvent. Combining multiple scenarios can cause conflicts if several scenarios adapt the same process, and can result in an intransparent generation of scenario databases. We propose an approach which enables a transparent and reproducible incorporation of multiple scenarios into a single background database. It builds on and extends already existing brightway libraries, such as wurst and the superstructure. The recently developed brightway library wurst allows to systematically incorporate electricity scenarios from one source, i.e., the integrated assessment model of IMAGE. Incorporating additional scenarios, e.g., with higher regional resolution or for more sectors, such as greener steel production, extends the scope and accuracy of future background databases. An example for regional conflicts would be the incorporation of both average electricity scenarios for Europe and specifically for Germany. Our approach builds on the superstructure principle which produces one scenario database combining the background database with the processes and flows required for the scenarios. Secondly, it generates excel sheets which specify the values of flows for all scenarios. The scenario database and scenario excel sheets can be imported into the activity-browser, the graphical user interface for Brightway. The activity-browser enables a scenario-based LCA calculation and interpretation, which is easy-to-use also for nonpythonic LCA practitioners. Moreover, the generated superstructure database along with the scenario excel sheets can be easily shared. Our approach provides an extension to the superstructure principle to resolve conflicts caused by different scenario sources. We aim at creating a reliable and reproducible workflow to transparently generate a superstructure database which consistently combines scenarios from multiple sources. The goal is to make this approach available to the LCA-community as an open-source tool. Thus, our proposed approach contributes to the usability of background scenarios, and facilitates the cooperation as well as the exchange of scenarios between LCA practitioners.