If one is to improve reliability and resilience in infrastructures, it is necessary to adopt a ‘complex, smart territory’ modelling strategy, particularly one that gives attention to the importance of social complexity. To test the veracity of their argument the authors conducted a case study on a segment of the US power grid, seeking to create a first proof-of-concept sufficient to show how thinking about infrastructures in ‘complex systems’ terms, primarily in terms of their social aspects, can prove beneficial. They employed the SACS Toolkit, which is part of the new approach to modelling complex systems, called case-based complexity. As a technique, the SACS Toolkit is a computationally grounded, case-comparative, mixed methods platform for modelling complex systems as sets of cases. In an effort to help readers make use of this technique, this chapter provides a basic overview of the research process, ending with a summary of the novel insights this approach was able to achieve.