Comparisons between direct and embodied natural gas networks: Topology, dependency and vulnerability

Natural gas was a type of alternative energy resources in the short and medium term to maintain energy consumption worldwide. Combining multi-regional input-output analysis and complex network modelling, this study examined the spatial-temporal evolution and topological structures of multi-layer natural gas networks, analyzed the network characteristics of different countries/regions, and tested the network robustness and vulnerability between direct natural gas trade network and embodied natural gas transfer network. From the results, the direct natural gas trade network was relatively flatter, while the embodied natural gas transfer network was more concentrated in core countries/regions. Moreover, the countries with natural gas reserves and highly industrialized levels occupied high statuses in the direct natural gas trade network, whereas the highly industrialized countries occupied the core position in the embodied natural gas transfer network. Among the two disturbance scenarios, both direct and embodied natural gas networks were more vulnerable under deliberate assault than under random failure, however, the direct trade network is easier to collapse compared with the embodied transfer network under deliberate assault. By constructing multi-layer natural gas networks from both direct and embodied perspectives, this study attempts to provide practical implications and suggestions toward sustainable natural gas network management worldwide.