Scenario-based analysis of future life cycle energy trajectories in residential buildings-A case study of inner Melbourne

Abstract

The residential building sector contributes significantly to energy use in Australia. However, future energy use in residential buildings is seldom evaluated from a life cycle perspective, and such analysis rarely provides details about potential energy savings by specific strategies. This study develops a scenario-based bottom-up approach to predict the future life cycle energy (LCE) trajectories in residential buildings to 2050 with different energy-saving strategies. The proposed approach is used to investigate the impacts of strategies on the future LCE of residential buildings in detail in four scenarios: high carbon (HC), business-as-usual (BAU), accelerated policy (AP), and net-zero emissions (NZE), for a case study of Inner Melbourne Cities. The results demonstrate the potential upward trajectory of operational energy (OE) in the HC scenario and a downward trend in the NZE scenario. The analysis also reveals how stringent energy-efficient strategies and increasing renewable energy supply could lead to future net-zero operational emissions in the NZE scenario by 2050. The most effective strategies for decarbonising the residential building sector include improving the building envelope efficiency, upgrading heating and hot water systems, and using renewable energy. Furthermore, embodied energy (EE) will contribute more to LCE after 2045 in AP and NZE scenarios with the decrease of OE. EE in the NZE scenario is higher than that in the other three scenarios, as energy-efficient dwellings usually use more insulation materials. Therefore, EE reduction is critical for achieving net-zero life cycle emissions in the residential building sector. Building stakeholders should synergistically promote demand-side, supply-side, and EE reduction strategies for achieving net-zero life cycle emissions. A detailed analysis of the future LCE development with different strategies shows the benefits of the proposed approach, which supports informed decision-making towards the 2050 net-zero emissions target.