A Methodological Approach to Prospective Life Cycle Assessment for the Harmonization of the Foreground and Background Systems

Kurzfassung

In the modern world, energy is generated or utilized by sectors like the power sector, industry, transport, and households. Going forward, all these sectors, including their technologies, will undergo massive transformations to achieve sustainable pathways. With the prospective life cycle assessment (pLCA), the future environmental impacts of these technologies can be evaluated over their life time, considering the changes in the foreground and background system. For instance, in the pLCA of fuel cells, the background system handles fuel cell material and energy flows like steel and electricity, while the foreground system includes activities linked to fuel cell's production and use. Future scenarios of both foreground and background systems will be decisive in pLCA for the selection of prospective technologies across the sectors. Most of the pLCA studies in the literature focus on the implementation of future scenarios in the foreground and background systems individually. Very few of them considered both and observed an inconsistency in the technology selection based on the perspective storylines. This occurs due to the lack of both scenario data and its assumptions of the background systems. Thus, there is a research gap in the identification of changes to life cycle and system data in the foreground in line with the background system. This contribution answers to how to carry out pLCA for a specific technology, considering the methodological approach of harmonizing the foreground with background systems? The research methodology involves three steps: identifying key elements in a background system to aid with harmonization, designing the foreground system, and integrating the gathered data of background system into Premise (a tool that facilitates the creation of prospective inventory databases). The proposed methodology will be tested by applying case studies in all the steps. As part of the harmonization with a decarbonized background scenario in a selected use case, technologies in the foreground, such as green hydrogen for fuel production and carbon capture and storage, were selected. This harmonization approach stresses the importance and inclusion of background systems in a foreground system design. On the other hand, decision-makers find it easier to select the prospective technologies of their choice when both systems are consistent. It will increase the accuracy of measurement of impact factors related to climate change and material resources.