Economic Impacts of Large-Scale Power Outages: Global Blackouts, Reliability Metrics, and Value of Lost Load

Large-scale power outages have become a major concern not only for power-system reliability but also for economic resilience, social continuity, and critical infrastructure security. This review examines the economic impacts of major blackout events by linking outage causes, reliability metrics, sectoral interruption costs, and Value of Lost Load (VoLL)-based assessment methods. To establish a consistent analytical framework, the paper distinguishes customer-based reliability indices from energy-based measures such as Energy Not Supplied (ENS) and Expected Energy Not Served (EENS). It also clarifies the role of adequacy metrics, including Loss of Load Probability (LOLP) and Loss of Load Expectation (LOLE), and microgrid-oriented indicators such as Loss of Power Supply (LPS) and Loss of Power Supply Probability (LPSP). The review emphasizes that probability- or duration-based indices cannot be directly converted into monetary losses unless they are first expressed as energy-not-served quantities. Evidence from major events, including India 2012, North America 2003, Italy 2003, Türkiye 2015, Texas 2021, Iberia 2025, and Chile 2025, shows that outage consequences depend on the interaction between technical failure mechanisms, interruption duration, affected sectors, restoration processes, and infrastructure interdependencies. The study concludes that future outage-cost assessments should rely on transparent data reliability levels, updated sectoral cost data, dynamic VoLL estimates, and dimensionally consistent links between reliability indicators and economic losses.