Power Outage in the Iberian Peninsula: Causes and Impacts
Introduction
On April 28, 2025, a massive power outage struck the Iberian Peninsula, affecting Spain, Portugal, and parts of southern France. The blackout, described as unprecedented in scale, disrupted essential services, including transportation, telecommunications, and healthcare, impacting millions of residents. Authorities have attributed the outage to a disturbance in the European electrical grid, with preliminary investigations pointing to a loss of solar generation in southwest Spain as a key trigger. However, the exact causes remain under investigation, with hypotheses ranging from technical failures to atmospheric phenomena, while cyberattacks have been largely ruled out. This article examines the outage’s causes, impacts, and ongoing efforts to restore power, drawing on recent reports and expert analyses.
Context of the Outage
The European Electrical Grid
The European electrical grid is a highly interconnected system that synchronizes power distribution across multiple countries, operating at a standard frequency of 50 Hz. Spain and Portugal, forming the Iberian Peninsula, are part of this grid but are considered an “energy island” due to limited interconnections with the rest of Europe, primarily through France. This relative isolation, exacerbated by the Pyrenees mountain range and technical constraints, restricts the peninsula’s ability to import or export large amounts of electricity during crises. The Iberian Peninsula relies heavily on renewable energy, with Spain generating 59% of its electricity from solar and 11% from wind power at the time of the outage.
Timeline of the Outage
The blackout began around 12:30 PM local time in Spain (11:30 AM in Portugal, 7:30 AM Brasília time) on April 28, 2025. Within minutes, the electrical systems in Spain and Portugal collapsed, with Portugal’s demand plummeting from 8.16 GW to 0.6 GW—a 93% reduction—and Spain losing approximately 15 GW of power. Parts of southern France and Andorra also experienced brief outages. By evening, partial restoration had begun, with 61% of Spain’s grid and significant portions of Portugal’s network, including Lisbon and Porto, regaining power. Full restoration in some areas was projected to take up to a week.
Causes Under Investigation
Preliminary Findings
The Spanish grid operator, Red Eléctrica, identified two consecutive events in southwest Spain as the trigger for the outage. Between 12:30 and 12:35 PM, solar photovoltaic generation dropped by over 50%, from 18 GW to 8 GW, causing instability that led to a disconnection from the French grid. This loss of generation, likely from solar plants, destabilized the Iberian system, which was exporting energy to France and Portugal at the time. The exact reason for the solar generation drop remains unclear, but experts suggest a combination of factors, including low grid inertia and potential synchronization failures.
Hypothesized Causes
Several scenarios have been proposed:
Solar Generation Volatility: Spain’s heavy reliance on solar energy (59% of supply) may have exposed the grid to vulnerabilities. The sudden loss of solar output could have been due to unexpected cloud cover, equipment failure, or grid management issues. Unlike hydroelectric or thermal plants, solar systems lack the inertia provided by large rotating turbines, making the grid less resilient to rapid changes. Pedro Jatobá, a Brazilian energy expert, compared the event to a 2023 blackout in Brazil caused by similar renewable energy intermittency.
Atmospheric Phenomena: Portugal’s grid operator, Redes Energéticas Nacionais (REN), initially suggested that “extreme temperature variations” in Spain caused “induced atmospheric vibrations” in 400 kV high-voltage lines, leading to synchronization failures. This claim was later retracted, with REN denying the statement, but it raised questions about weather-related impacts on infrastructure.
Grid Interconnection Failure: The outage may have originated from a disconnection in the Spain-France interconnection, possibly triggered by the solar generation loss. Eduardo Prieto, Red Eléctrica’s operations director, noted that the grid recovered from the first event but collapsed after the second, suggesting a cascading failure. The French operator, RTE, reported that France disconnected from Spain as a precaution, limiting external support.
Cyberattack Speculation: Early speculation about a cyberattack was fueled by social media and some officials, including Portugal’s Minister of Territorial Cohesion. However, Red Eléctrica, REN, and the European Commission found no evidence of cyber interference. Spain’s Supreme Court announced an investigation to rule out terrorism or cyberattacks definitively.
Dismissed Theories
Excess Renewable Energy: Spanish Prime Minister Pedro Sánchez explicitly stated that the outage was not caused by an oversupply of renewable energy, noting that demand was low and supply was adequate.
Human Error: Red Eléctrica reported no indications of human error in the initial analysis.
Extreme Weather Events: While REN’s retracted statement mentioned temperature variations, no confirmed meteorological event, such as a storm, was linked to the outage.
Impacts of the Outage
Infrastructure and Services
The blackout caused widespread disruption across multiple sectors:
Transportation: Metro systems in Lisbon, Porto, Madrid, and Barcelona halted, stranding passengers in dark stations. Spain’s high-speed rail operator, Renfe, suspended services, leaving 35,000 passengers stranded across 100+ trains. Traffic lights failed, causing chaos in urban areas, with police deployed to manage intersections. Airports, including Lisbon and Madrid, operated on backup generators but faced delays and cancellations.
Telecommunications: Internet traffic dropped by 90% in Portugal and 80% in Spain, and mobile networks were disrupted, forcing some residents to revert to SMS.
Healthcare: Hospitals switched to generators, but non-emergency procedures were suspended. Water utilities, like Lisbon’s EPAL, urged conservation to prioritize critical services.
Commerce and Banking: Stores and restaurants closed, and ATMs failed, prompting cash withdrawals and long lines. The Madrid Open tennis tournament was paused due to power-dependent systems, including electronic refereeing.
Industry and Economy: Industrial operations stalled, and businesses faced significant losses. Gas demand in Spain fell from 27 GWh/hour to 8 GWh/hour as backup systems struggled.
Social and Political Response
The outage triggered emergency measures:
Spain: The government declared a national emergency, mobilizing 30,000 police officers. Sánchez convened crisis meetings and urged citizens to avoid speculation, emphasizing restoration efforts. By April 29, 99% of Spain’s grid was restored.
Portugal: Prime Minister Luís Montenegro assured the public that the issue originated outside Portugal, likely in Spain, and ruled out a cyberattack. A Council of Ministers meeting was scheduled for April 29 to assess the situation.
European Union: The EU, led by Commissioner Dan Jorgensen, launched an investigation, and operators like France’s RTE provided 700 MW to aid Spain’s recovery.
Public sentiment, as reflected on X, highlighted frustration and fear, with posts describing a “sense of the end of the world” and chaotic scenes in Lisbon and Madrid. Misinformation, including false claims of a 72-hour restoration timeline or Russian cyberattacks, spread rapidly but was debunked by authorities.
Restoration Efforts
Progress and Challenges
By April 29, significant progress was made:
Spain: Red Eléctrica restored 82.4% of the grid by 2:50 AM local time, with 45% of substations energized by mid-afternoon on April 28. Regions like Catalonia, Galicia, and Andalusia saw early recovery.
Portugal: REN reported that 147 substations were partially operational by 9:30 PM on April 28, serving 2 million of 6.5 million customers. Lisbon and Porto saw partial restoration by evening, with full normalization expected within days.
France and Andorra: Outages were brief, with RTE restoring power in southern France within minutes.
Restoration was complicated by the peninsula’s limited interconnections, forcing reliance on internal resources like gas and steam turbines. The process required careful synchronization to avoid further instability, with estimates ranging from 6–10 hours for Spain to up to a week for Portugal’s full recovery.
Recommendations for Residents
Authorities issued guidelines to mitigate impacts:
Energy Conservation: Residents were urged to minimize electricity use, such as avoiding non-essential appliances, to reduce strain on recovering grids.
Safety Precautions: People were advised to use flashlights instead of candles to prevent fires and to check food safety in refrigerators affected by prolonged outages.
Communication: With mobile networks strained, SMS and emergency radio channels were recommended for critical updates.
Conclusion
The April 28, 2025, power outage in the Iberian Peninsula exposed vulnerabilities in Europe’s electrical grid, particularly Spain’s reliance on solar energy and the region’s limited interconnections. While preliminary findings point to a sudden loss of solar generation as the trigger, ongoing investigations aim to clarify the cascade of failures that led to the blackout. The outage disrupted millions of lives, highlighting the need for resilient infrastructure and diversified energy sources. As Spain and Portugal work toward full restoration, the event has sparked calls for stronger grid investments and international cooperation to prevent future crises. The lessons from this blackout will likely shape energy policies across Europe, emphasizing the balance between renewable energy adoption and grid stability.