Iberian blackout: let the finger pointing begin

On 28th April 2025, the Iberian Peninsula experienced a major power outage, leaving millions without electricity for much of the day. This event highlights key challenges as Europe pursues ambitious renewable energy targets. 

Fill out the form at the top of the page for a look at part one of our recent report on the Iberian power outage. Please read on for a short summary of a couple of the report’s key points:

The causes 

The blackout occurred during a period of high renewable generation, with solar, wind and hydro providing over 100% of Spain's demand. Just before the outage, Spain was exporting 4.3 GW of surplus power to France, Portugal, and Morocco and leveraging another 3 GW to restock pumped hydroelectric facilities.  

Three key factors contributed to the system's vulnerability: 

1. High renewable penetration: Solar corresponded to 56% of peninsular generation, while more than 70% of production came from non-dispatchable sources. 

2. Reduced conventional capacity: High forecast renewable production and moderate demand crowded out thermal capacity including several nuclear plants that were offline due to economic pressures from low power prices. 

3. Limited interconnection capacity between the Iberian Peninsula and France which is a fraction of the level recommended per EU guidance.  

There were several grid frequency issues that morning though the event unfolded rapidly: 

• A frequency drop at 12:33, likely from generation loss in southwest Spain, was initially absorbed. 

• Seconds later, a second frequency variation triggered disconnection from the French grid. 

• The frequency imbalance and decoupling from France was followed by a cascade effect and system-wide blackout. 
  
  By the following morning, 99.95% of demand had been restored. However, the incident raises important questions about grid stability and energy policy. 

The impacts 

Key implications include: 

• Scrutiny of Spain's 2030 ambitious renewable energy targets. 

• Debate on the timeline of Spain’s planned nuclear fleet phase-out. 

• Push for increased system flexibility and storage. 

• Discussion on expanding interconnections with France.

While Spain's government remains committed to the energy transition, we expect increased debate about nuclear phase-out plans and increased focus on grid security and resilience. What will be the impact on renewable asset owners and developers? Could centralised support for new PV and onshore wind lose momentum?  

This event serves as a critical case study for policymakers and grid operators across Europe as the continent pursues ambitious decarbonisation goals. You can find out more about our conclusions for policy impact by reading the full version of part one of our recent report on the Iberian power outage. 

Learn more 

To access a short extract from part one of the report, containing more detailed graphs as well as some of our conclusions for policy impact, please fill out the form at the top of the page. Plus, stay tuned for our second instalment of this report – coming later this week.