On a Monday in Joliet, Illinois, a power failure brought one of Exxon Mobil's most consequential American refineries to a standstill — a reminder that the vast machinery of modern energy rests on the fragile continuity of electrical current. The controlled shutdown, chosen to protect workers and equipment over production, raises quiet but urgent questions about how tightly wound our fuel supply chains have become, and how little slack remains when a single node in the system goes dark.