Energy system analyses of the marginal energy technology in life cycle assessments

In life cycle assessments consequential LCA is used as the “state-of-the-art” methodology, which focuses on the consequences of decisions made in terms of system boundaries, allocation and selection of data, simple and dynamic marginal technology, etc.(Ekvall & Weidema 2004). In many LCA studies, the energy demand applied is decisive for the results. In this extended abstract, consequential LCA methodology is examined with electricity as the case. The aim is to answer three questions: Which are the expected vs. the actual marginal electricity production technologies and what may be the future marginal technology? How is the marginal technology identified and used today? What is the consequence of not using energy system analy- sis for identifying the marginal energy technologies? The use of the methodology is examined from three angles. First, the marginal electricity technology is identified in historical and potential future energy systems. Subsequently, key LCA studies of products and different waste flows are analysed in relation to the recom- mendations in consequential LCA. Finally, a case of increased waste used for incineration is examined using an energy system analysis model. The differences in applying energy system analysis compared to assum- ing a marginal electricity technology are illustrated. Through the analysis, the current recommended ap- proach of consequential LCA is challenged. In the conclusions, recommendations for identifying affected technologies for consequential LCAs are made.