Life cycle assessment of energy supply contracted heat supply systems: A case study from Austria

• Life cycle assessment of energy supply contracted heat supply systems. • Both embodied and operational impacts are included for 18 impact indicators. • Systems operated on the basis of energy supply contracting lead to lower impacts. • This is due to the efficiency of the system, which is about 16% higher. • Efficiency is found to be the most influential parameter of the system. Heat supply systems (HSS) have the particularity that their energy-related services can be outsourced to a third party or contractor, which is usually referred to as energy supply contracting (ESC). Although the economics of ESC have been extensively researched, life cycle assessments of HSS with ESC are rather rare. The aim of this study is to assess the environmental impacts of an HSS operated in Austria, from cradle to grave. The measured energy consumption is used to assess the operational impacts, thus eliminating the need for calculation assumptions regarding efficiency and heat demand. In addition, the trade-off from using more efficient components in HSS, which possibly leads to higher embodied emissions prior to commissioning, is explored. Overall, our results suggest that systems operating with an ESC display better environmental performance, assuming an efficiency difference to conventional HSS of around 16%, even if this leads to higher embodied impacts. To support these conclusions, the next step would be to model these systems in dedicated software. This would also provide a further opportunity to investigate options for further improvements to the systems under consideration.