Why a Complete Blackout in Greece is Difficult but Not Impossible

A mere five seconds were enough to cause Greece to lose 60% of its electricity supply on April 28, 2025. The country witnessed an abrupt disappearance of 15 gigawatts, and it took approximately ten hours for power to return to satisfactory levels. As of now, the exact causes remain unknown. The only available information comes from Portugal, which mentioned an extreme weather event causing a blackout in transmission lines. However, Spanish authorities have not issued any statement if this scenario holds true. The network operator has detailed data covering second-by-second events, sparking theories about potential cyberattacks. In such massive outages, a rapid sequence of events occurs where one issue triggers a chain reaction. Historically, large blackouts have been caused by something as simple as an animal entering a transformer. Subsequently, power stations automatically shut down one by one to prevent permanent damage. The entire grid is designed with this logic to recover quickly and protect equipment. Industry professionals are aware that emergencies are part of their job, and managers are prepared for various scenarios like accidents, natural phenomena, cyberattacks, or even solar storms and eclipses. This applies to Greece, where ADMIE manages a modern grid after investing billions in maintenance, upgrades, and security. Natural disasters experienced in recent years have led to revising the entire approach, focusing mainly on the distribution network but also touching transmission. Additionally, following the energy crisis and the war in Ukraine, the Greek operator along with European counterparts has devoted significant effort to addressing potential asymmetric threats, incorporating new tools and defenses regarding cybersecurity. Despite these measures, it’s widely accepted that the possibility of a blackout remains, especially with a more complex system based on decentralized production across the country through RES. The goal isn’t complete elimination but minimization of this possibility. Crucially, the response time matters—how quickly can operators restore the system fully? In Spain’s case, recovery took less than a day due to swift and effective action.