The city of Heerlen, in the post-mining Parkstad Limburg region in the Netherlands, runs on a layered energy substrate: electricity (Enexis as DSO, TenneT upstream), natural gas (legacy infrastructure on a national wind-down path), the Mijnwater mine-water district heating-and-cooling network operated by Mijnwater B.V., and a building stock dominated by postwar housing largely owned by social-housing corporations. Its consumers are heterogeneous — households across a wide income spectrum, SMEs, Zuyderland hospital, schools, public buildings, a small industrial base. What is the structure of this energy dependency network — who depends on whom across these layers, where are the single points of failure (physical, operational, contractual), and where do those failure modes map onto social fault lines such that an outage or curtailment hits some neighborhoods and consumer classes far harder than others?