Urban Energy Carrying Capacity- A Evaluation Method on Sustainable Urban Energy System

An innovative concept of urban energy carry capacity (UECC) is introduced in this paper, which evaluate the degree of urban energy sustainability based on the relationship between energy system and city. The UECC model is established in hierarchical structure with pressure and bearing force layer. The pressure layer contains energy and environment indicators system, which cause pressure to city due to energy consumption and environment emission. The bearing force layer contains indicators system of urban resources, energy infrastructure, environmental protection, economy and society system, which support the urban energy system to maintain well condition. The ratio of pressure to bearing force is used to assess the degree of UECC. Then the case of Beijing city is analyzed. It shows that energy system in Beijing has develop from overload of carrying capacity to full load at present and may be reach at balance of carrying capacity in 2020. This paper comes to conclusion that urban energy sustainability can be achieved when urban energy efficiency improved, energy infrastructure and environment protection strengthened, and resource-conserving society set up to promote the ability of UECC.