Energy security and sustainable design of urban systems based on ecological network analysis

Due to the huge energy demand and the influences from the technology, cost, production, and consumption structures, urban system has become a hot topic for the assessment of the energy security of energy systems. In this study, all the energy sources of the energy system of Tangshan, an industrial city that primarily depends on energy resources in Hebei Province, China, have been chosen as case study. Additionally, the metabolism theory from ecology is introduced to subdivide the sectors of system into producers, primary consumers, and secondary consumers and to trace the energy flows among them. The stability analysis includes the resilience and the restructuring capacity when facing disruptions and reflects the stability of the energy supply system and energy security. Flow and information-based analyses from ecological network analysis method are used to quantify the developing capacity, stability, and efficiency of the network from 2006 to 2016. The results indicate that that the heat supply, coking, gas generation, and coal products sectors were the providers of the integral energy of the system. In contrast, the industrial and household sectors were the receivers. The stability analysis indicated that, as the system's resistance ability to disturbance grew, the system was more stable. However, the system itself still had specific problems including large energy consumption quantities from the industrial sector, and large heat consumption from the household sector. And this is related to the coastal area development and industrial restructure in Tangshan. Therefore, the analysis provides a tool for evaluating stability of an energy system from the perspective of energy supply.