Related article: one of our co-founders experienced the historic blackout in New York in 2003.

The unprecedented power outage that struck Spain, Portugal, and parts of France on 28 April 2025 offers several critical lessons for policymakers, grid operators, and the public. Here are the main takeaways:

1. Grid Vulnerability and Interconnection Risks

• The blackout was triggered by a technical fault-likely a critical transmission line outage in France-which severed the Iberian Peninsula from the European synchronous grid. This isolation led to a rapid supply-demand imbalance and a cascading collapse of the Spanish and Portuguese grids.

• The event highlights the vulnerability of national grids to faults at interconnection points, especially when interconnection capacity is limited and system inertia is low due to high renewable penetration.

2. Renewable Energy and System Stability

• Spain’s heavy reliance on renewables, which provide less system inertia than traditional power sources, contributed to the rapid destabilization of frequency and made the grid more susceptible to collapse under stress.

• The blackout raises questions about the pace of nuclear and coal plant closures and the need for robust backup and balancing mechanisms as the energy transition accelerates.

3. Importance of Emergency Protocols and Coordination

• The swift activation of emergency protocols by grid operators, authorities, and essential services (hospitals, airports, etc.) prevented a larger humanitarian crisis. Backup systems and coordinated responses ensured critical infrastructure continued to function.

• International cooperation between Spanish and Portuguese grid operators was instrumental in containing the incident and preventing a wider European blackout.

4. Communication and Public Response

• Clear, timely communication from authorities and grid operators via social media and radio helped manage public anxiety and provided essential updates, even as internet and mobile networks were disrupted.

• The public’s calm and responsible response, with minimal incidents despite widespread disruption, was crucial in avoiding chaos and allowing emergency services to focus on critical needs.

5. Need for Investment in Grid Resilience

• The event is a “wake-up call” for Europe, underscoring the need for greater investment in grid modernization, real-time monitoring, smart grid technologies, and increased interconnection capacity across EU member states.

• Enhanced grid resilience will be essential as Europe’s energy systems become more integrated and dependent on variable renewable sources.

6. Ongoing Investigation and Uncertainty

• While initial fears of cyberattack or sabotage have been largely dismissed by grid operators, the precise technical causes remain under investigation. Authorities are examining the sequence of disconnection events and the structural weaknesses that allowed a local fault to escalate into a continental-scale blackout.

• The incident has prompted Spain’s government to set up a commission to ensure such a failure does not recur, with criminal courts also probing possible sabotage as a precaution. 

What a day! Today’s massive #blackout across #Spain and #Portugal instantly transported me back to August 15, 2003, when I was on assignment with Swiss Re, relocated from Zurich to New York for a project. Imagine this: just two years after 9/11, I’m in a bustling upstate New York office, surrounded by rows of cubicles and the ever-present hum of neon lights.

Suddenly, everything stopped. My call was cut off mid-sentence. The red lights on the phones blinked out. The overhead lights faded, and a strange hush fell over the office. In that moment, uncertainty took over-was this another attack? No one could reach the outside world; all communications were down. Trains weren’t running. The city that never sleeps was eerily still.

With no news and no way home but my own two feet, I decided to set out for my hotel in downtown Manhattan-1.5 hours away by public transport, now paralyzed. The only certainty was uncertainty itself. I grabbed some water and bananas and started the long trek, not knowing what I’d find.

But here’s the twist: what could have been a dramatic and stressful time turned into an amazing experience. I managed to hop on a few buses, and everywhere I went, people were surprisingly friendly. There was a surreal, almost “end of the world” feeling in the air, but instead of panic, there was #camaraderie. Strangers shared drinks, played guitar in the streets, and helped each other out. The city came together in the most unexpected way.

There was a lot of rumours on what had happened, but it’s only after quite a while that I got the information: A single power line in northern Ohio brushed against overgrown trees, triggering a chain reaction that exposed critical weaknesses in the grid’s monitoring and coordination. Within minutes, what began as a routine summer afternoon spiraled into a historic blackout, plunging over 50 million people across the US and Canada into darkness.

Today’s blackout across Iberia brought back all those feelings: the sudden silence, the collective confusion, and, most importantly, the incredible mutual aid and #fraternity that emerges when we face challenges together. It’s in these moments that we see the true strength of our communities.

My thoughts are with everyone affected today-I’m wishing you all to be safe and a swift return to normalcy.

#Resilience, #adaptability, and community spirit are what carry us through.