Blackout risk is the chance that electricity supply cannot reliably meet demand, leading to partial or total loss of power. In cyber security, this matters because modern infrastructure depends on digitally controlled grids, substations, and industrial systems. If attackers disrupt those systems, they can reduce generation, interrupt transmission, or prevent operators from balancing supply and load.
Blackout risk appears in real attacks when malware, credential theft, or sabotage targets operational technology and control networks. Defenders reduce it with network segmentation, strong authentication, monitoring, fail-safe controls, redundant power paths, and tested recovery procedures. It is a resilience metric as much as a physical one: the more an environment relies on software, automation, and remote control, the more important it is to protect availability, not just data confidentiality.