Energy consumption and greenhouse gas emissions by buildings: A multi-scale perspective

Since the construction stage of buildings is heavily dependent on supports from urban, national and global economies, a hybrid systems analysis combining input-output analysis and process analysis is conducted in this work from a multi-scale perspective. Based on the multi-scale intensity databases, the embodied energy consumption and greenhouse gas emissions driven by the infrastructure engineering of case buildings in Beijing are systematically quantified at urban, national, and global scales with primary inputs in particular steel, cement, lime, and metal products. By tracing sources along the supply chains, the effects of building construction at the urban, national and global scales are calculated as 39.12%, 55.21%, and 5.67% of energy consumption and 68.78%, 24.41%, and 6.80% of greenhouse gas emissions, respectively. In general, basic materials (such as metal and petroleum) are mainly supplied by global scales, while synthetic materials (such as paints, fiber and rubber) are generally re-processed and transported within China. The energy consumption per area of the case buildings in E-town from urban, national and global scales are 3.03 GJ/m2, 4.27 GJ/m2 and 0.44 GJ/m2 respectively. Correspondingly, the related greenhouse gas emissions of the three scales are 0.40 t CO2-eq/m2, 0.14 t CO2-eq/m2 and 0.04 t CO2-eq/m2 respectively. With overall impacts of the construction engineering at urban, national, and global scales, the multi-entities responsibility assignments and tele-connected coordinate efforts for overall consumption and emission abatement could be derived from a multi-scale perspective.