On April 28, 2025, a massive electricity blackout swept across Portugal, Spain, and parts of Southwestern France, causing widespread disruption to electricity supply, telecommunications, transport, and emergency services. For infrastructure operators, the event offers critical insights into vulnerabilities and preparedness strategies. This article by Paulo Barreto, General Manager of Egis Portugal, summarises the key causes, impacts, and lessons learned, providing actionable guidance for operators responsible for essential services.
Understanding the causes and impact
The blackout originated from overvoltage and cascading failures at Spanish substations, particularly in Granada, Badajoz, and Seville, shortly after midday on Monday, 28th April. These failures disconnected the Iberian Peninsula from the broader European power grid. Portugal was completely isolated, while Spain leveraged interconnections with France and Morocco for recovery. France experienced only brief outages in the southwest and played a supporting role in Spain’s recovery.
The consequences were severe: Portugal took nearly five hours to reestablish its grid and ten hours to restore full electricity. Spain required approximately sixteen hours for full restoration, while France experienced minimal disruption.
There were indirect fatalities, seven in Spain and one in Portugal, which were linked to candle accidents, generator fumes, and fire outbreaks. Watch this video for the personal account of Paulo Barreto, General Manager of Egis Portugal, which operates the A24 Motorway.
Widespread impacts with some unexpected consequences
Hospitals and medical services: Many hospitals switched to backup generators, but some faced delays or failures. Emergency surgeries were postponed, ICUs rationed power, and ambulance dispatches reverted to manual coordination.
Fire and rescue: Fire departments reported a surge in incidents, including fires from candles and generator malfunctions. Traffic light failures and communication breakdowns hampered rescue operations and slowed response times.
Police and public safety: Police increased patrols to prevent looting and maintain order in darkened urban areas. 911 and 112 emergency lines experienced outages or overloads, forcing some regions to use temporary hotlines. Transportation: Traffic lights and public transport systems failed, causing chaos at intersections and halting underground metro systems and trains. This forced more people onto the roads, making congestion even worse. Fuel stations shut down leading to long queues and fuel shortages. Airports were severely disrupted and the effects spilled over onto surrounding roads, causing delays and confusion. Electronic payments and tolls went offline.
Communication and coordination: Mobile networks and internet services were partially down, complicating coordination between agencies. Civil protection services in Portugal operated with limited data, relying on radio and pre-established protocols.
Three key takeaways for infrastructure operators
Increase power independence
- Invest in generators, ensure proper maintenance and sufficient fuel supplies - fuel delivery was challenging during the blackout due to limited fuel stations having backup power generators.
- Consider solar or other autonomous power sources to enable continuous operation, as uninterruptible power supply (UPS) systems may not be sufficient for extended operations across all affected infrastructure.
- Electric vehicle fleets paired with on-site generators offer greater operational resilience than fuel-based fleets.
Establish robust communication backups
- The blackout disrupted both phone and internet services, exposing vulnerabilities in systems reliant on online connectivity.
- Satellite-based communication may offer more reliable backup than radio systems, which depend on powered antennae.
- The growing reliance on cloud-based platforms increases exposure to power-related disruptions; local fail-safes should be considered.
Develop and drill emergency plans
- Pre-event planning: conduct risk assessments, define operational objectives, allocate resources, and establish minimum service protocols.
- Real-time adaptation: implement monitoring tools, decision-making frameworks, and clear communication channels during crises.
- Training and simulation: regular drills, role assignments, and feedback loops help ensure readiness.
- Stakeholder engagement: promote transparency, encourage collaborative input, and conduct joint exercises to align response strategies.
The 2025 blackout highlighted how deeply interconnected and dependent our infrastructures are on reliable electricity. Infrastructure operators must prioritise resilience, cross-sector coordination, and robust backup systems to mitigate the impacts of future large-scale outages.
