This paper presents a methodology for the characterization of vulnerability within current and future configurations of large-scale electricity network systems. We provide a demonstration for Great Britain using a spatial hierarchical network representation of the transmission and distribution infrastructure consisting of more than 180,000 nodes. Alongside the current configuration, we develop nuclear and renewable future configurations by assigning known and forecast capacity and demand values to individual generator and load-point network assets. A capacity constrained shortest-path resource allocation model has been used to map flow pathways between generators and load centers, providing a path-set that bridges multiple scales. Vulnerability is characterized by exploring the distribution of path lengths and the number of intermediate components of the path set. Results highlight that a renewable future configuration has a reduced number of very long paths, resulting in a reduced vulnerability of exposure to hazards when compared to a nuclear future.