Significance of fixed assets in life cycle assessments

Accounting for fixed assets in life cycle assessments is often ignored. Fixed assets represent machinery, equipment and constructions, which are utilized in the life cycle of products to enable their production and use. Subject matter is the set-up of an input–output model to implement fixed assets, followed by a methodological analysis of the approach and structural analysis of the determined coefficients. The study is based on an input–output model in hybrid units, which measures nine energetic transactions in energetic units and 64 other transactions in monetary units. An environmental extension takes renewable energies and greenhouse gases into account. Specific cumulative energy demands and emissions are determined. Fixed assets are implemented by either the augmentation method or the matrix flow method. Energetic and ecologic coefficients rise by 20–30 % on average, and in particular for services, if fixed assets are considered. Applying these coefficients to a life cycle assessment of an offshore wind farm indicates about 12% higher values for the energy demand and emissions. The augmentation method is easy to implement and delivers approximately the same energetic coefficients for fixed assets, compared to the matrix flow method. For a holistic analysis, the significant additional energy demand and emissions for fixed assets have to be included in life cycle assessments. In particular, the indirect share and especially machinery and equipment have to be considered. Recommendations on the modeling, as well as coefficients for fixed assets, to be implemented in future life cycle assessments, are delivered.