Power Outage in Spain and Portugal Affects Millions
Summary of the outage
- Start time: April 28, 2025, at 12:32 pm CEST (10:32 UTC).
- Affected regions: Entire Iberian Peninsula (Spain, Portugal, Andorra) and parts of southeast France.
- Immediate impacts: Train and metro services halted, airports grounded, businesses and schools closed.
- Communications: Cellular networks remain operational via UPS and generator backups.
Technical background: grid oscillation and system stability
According to Spain’s grid operator Red Eléctrica de España (REE), the blackout was triggered by an uncontrolled grid oscillation. In an AC network synchronized at 50 Hz nominal frequency, all generation units and major loads must remain phase‐locked. Oscillations can occur when the system’s inertia (traditionally provided by large synchronous generators) is insufficient to damp rapid power swings. The Iberian grid, with a peak load of approximately 80 GW and limited interconnection capacity (2–3 GW of HVDC links to France), is more vulnerable to low‐inertia events as variable renewables proliferate.
Phasor measurement units (PMUs) in REE’s Wide Area Monitoring System (WAMS) recorded frequency deviations exceeding ±0.2 Hz within seconds prior to the outage. When damping coefficients fall below critical thresholds, power swings can grow rather than decay, leading protection relays to isolate segments and triggering cascading trips.
Immediate infrastructure impacts
- Transportation: Over 90% of trains and metros in Madrid and Lisbon ground to a halt. Many passengers were evacuated via emergency power in tunnels.
- Airports: Madrid-Barajas and Lisbon-Portela suspended all operations; backup diesel generators powered only essential control towers.
- Telecom: Cell towers switched to UPS (4 hours capacity) and diesel gensets; 5G data networks remain up, though congestion is rising.
- Data centers: Tier III facilities maintained operation with N+1 UPS and standby generators; some edge sites without backup have gone dark.
On-the-ground report from Lisbon
Local resident Tiago Carvalho describes widespread closures of banks and supermarkets, with only cash accepted at a few open shops. Traffic lights are out, prompting heavy congestion and honking. Battery-powered radios and 5G hotspots are the primary news sources. Carvalho estimates at least 48–72 hours before full restoration.
Expert analysis: resilience and modernization of the Iberian grid
“This blackout underscores the need for enhanced inertia and smarter control schemes,” says Dr. Marta Pérez, senior grid engineer at REE. She advocates for synthetic inertia from inverter-based resources (wind and solar plants) and deploying advanced damping controllers in grid-forming inverters. Proposed upgrades include:
- Deployment of 200 additional PMUs for real-time modal analysis.
- Installation of 500 MW of grid-scale battery storage for fast frequency response (FFR) within <50 ms.
- Strengthening HVDC ties to France and Morocco to raise interconnection capacity above 5 GW.
Cybersecurity considerations
While ENISA has ruled out a cyberattack as the primary cause, the incident raises questions about ICS and SCADA security. “Network segmentation and multi-factor authentication for remote terminal units (RTUs) must be enforced,” says Dr. Elena Kostova, cybersecurity researcher at ENISA. She points to IEC 62443 standards and daily penetration tests of control centers to ensure robust defense against spoofing or man-in-the-middle threats.
Looking ahead: policy and investment implications
The European Commission’s Green Deal calls for a 40% increase in interconnection capacity by 2030. To meet resilience goals, national regulators are considering:
- Incentivizing distribution-level microgrids with combined heat and power (CHP) units.
- Mandating 30 minutes of contingency reserve in all transmission operators.
- Deploying AI-driven demand-response platforms to smooth peak loads using machine learning predictions of consumption patterns.
This is a developing story. We will update as further details, official reports, and expert commentary become available.