Simulation of the evolution of the Chinese building and infrastructure stock

During China's rapid urbanization and modernization process, the energy and mass flows as well as the related environmental impacts of the Chinese building and infrastructure stocks deserve attention due to the high volume of construction activity, the possibly short lifespan of the new constructions, and the increasing need for energy and construction materials, which have already led to severe environmental impacts. The objective of this study is to model the energy and material input and output through the construction and operation activities in the reference year (2005) to estimate future development during the ongoing urbanization process (until 2050) under present conditions (Trend scenario) and to formulate alternative scenarios with reduced resource consumption and environmental impacts. An integrated life cycle assessment (LCA) model is proposed by taking into account the material and energy flows and the related environmental impacts through a combined bottom-up and top-down approach. The historical evolution from 1978 to 2005 is analysed as a basis for the forecasting projections. The different age classes of the stock are modelled as cohorts classified by use and by type (urban/rural). The transitions of the key parameters follow a logistic function. The results show the possibilities and limitations of alternative long-term developments. The limitations of the model both in structure and input data are discussed.