CO2 emissions from urban buildings at the city scale: System dynamic projections and potential mitigation policies

To reduce energy-related CO2 emissions from the urban building sector, multiple diverse energy efficiency policies are often simultaneously implemented by different government entities. Thus, evaluating and quantifying the effects of these policies are important for improving their efficacy and prioritizing them. In this paper, a projection of the long-term CO2 emissions from city-scale urban buildings whose energy use and construction are governed by multiple diverse policies is presented. A system dynamics (SD) model is established to simulate the causal path through which different policies directly and indirectly affect the energy use of and CO2 emissions from buildings in the urban building stock, and the model is applied to Beijing, China. The results show that under the existing set of policies, the primary energy use by urban buildings in Beijing will peak around 2025 and that energy-related CO2 emissions will peak around 2022. The model also reveals interference between the policy for promoting green building construction and the policy limiting the urban building stock area. Targeted measures for improving and prioritizing these policies are suggested, and implications for policy design and implementations are proposed. The framework developed in this study can be used not only to project long-term energy-related emissions from building sectors but also to evaluate the effects of policies on emissions. Suggestions for adapting the model to more general cases are provided.