Blackout in Italy 2003 and Spain 2025, causes, impacts and comparison

Il blackout that hit Spain and Portugal April 28, 2025 brought back memories of the great electrical collapse which left Italy in the dark in 2003. Two events separated by over twenty years, but united by a structural fragility that has brought entire countries to their knees.

Let's analyze the causes, effects and differences between the two episodes to better understand how crucial the resilience of national electricity networks is.

@tg1rai And on what is happening in Spain and Portugal we heard from an expert, who explains: "This #blackout It recalls what happened in Italy in 2003". #Tg1 ♬ original sound – Tg1Rai

Causes and dynamics of the 2003 blackout in Italy

On the night between September 27 and 28, 2003, at 3:01 am, a tree fell on a high voltage line in Switzerland, causing a short circuit and the interruption of the energy supply to Italy.
Il overload of remaining lines caused a domino effect that led to a total blackout of the country, with the exception of Sardinia and some smaller islands.

The consequences of the 2003 blackout in Italy

• Total power outage: Italy was without electricity for several hours, with the North seeing power restored around 9:00 am, the Centre at 16:30 pm and the South at 19:00 pm.
• Transport disruptions: 110 trains blocked with 30.000 passengers on board, subways stopped and traffic lights turned off.
• Health Emergencies: hospitals forced to operate with emergency generators, with critical situations in some facilities.
• casualties: four deaths directly attributed to the blackout.
• Economic damage: estimated at around 100 million euros, with serious repercussions on the agricultural and commercial sectors. Source: ​Wikipedia

Spain and Portugal's 2025 Blackout: A New Alarm Bell?

Causes and dynamics of the blackout in Spain and Portugal

On April 28, 2025, at 12:33 PM, a sudden loss of about 15 GW of energy, equivalent to 60% of Spanish consumption, has caused a collapse of the electricity grid that has extended to Portugal, Andorra and part of southern France.
The exact causes are still under investigation, but it is hypothesized a failure or mismatch in solar power generation in southwest Spain, which destabilized the system and caused it to be disconnected from the European grid.

The consequences of the Blackout in Spain and Portugal

• Interruption of essential services: public transport, hospitals, airports and telecommunications paralyzed for hours.
• casualties: at least five deaths directly linked to the blackout.
• Economic damage: estimated at around €1,3 billion, with significant impacts on sectors such as hospitality and retail.
• Gradual recovery: Electricity supply was gradually restored, reaching 99,95% by 7:00 a.m. on April 29.

@the Republic

In Spain and Portugal, electricity is slowly returning to service after the massive blackout that disrupted connections and infrastructure in both countries and parts of southern France. Both countries have declared a state of energy emergency.

♬ original sound – la.repubblica

Comparison of the two blackouts

Similitudes

• National scope: both events affected the entire national territory, causing widespread disruption.
• Domino effect: A single failure triggered a series of problems that led to the collapse of the entire network.
• Disruptions to essential services: transport, health and communications seriously compromised.

Differences

• Triggers: in 2003, a physical event (fallen tree); in 2025, a possible failure or misalignment in solar energy production.
• Blackout duration: longer in 2003 (up to 18 hours), shorter in 2025 thanks to more efficient recovery systems.
• Economic impact: greater damage in 2025, with estimates exceeding one billion euros.
• Energy context: in 2003, dependence on traditional sources; in 2025, greater integration of renewable energy, which has introduced new vulnerabilities.