Earlier today we wrote about the ‘News Release on the blackout on the Iberian Peninsula (on 28th April 2025) suggests overvoltage was the cause’.
At that time I could not find the full report – but have since been pointed to this 182-page ‘Non-confidential version of the report of the committee for the analysis of the circumstances surrounding the electricity crisis of April 28, 2025’ here:
Alas, for luddites like me (who can’t speak Spanish) it’s pretty incomprehensible – so if someone can point to a ‘translated to English version’ in the comments, some readers would say thank-you!
PS1 … the report in (machine-translated) English
One of the other people on LinkedIn I am connected with, Lion Hirth, has helpfully attached a machine-translated English version of the report to his update this evening here.
Used Co-pilot to translate and summarise in 1 page – could ask for a full translation if you want one:
Here is a **1-page summary** of the **non-confidential report from the Committee of Analysis on the April 28th Electricity Crisis** (“Informe no confidencial Comité de análisis 28A”):
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### **Summary: April 28, 2025 Iberian Electricity Crisis Report**
On April 28, 2025, at 12:33:30, the Iberian Peninsula experienced a **complete voltage collapse**, disconnecting Spain and Portugal from the European electricity grid. This unprecedented event triggered a formal electricity crisis declaration under EU Regulation 2019/941. The Spanish government established a multidisciplinary **Committee (28-A)** to investigate the causes, impacts, and propose corrective measures.
#### **Key Findings**
– **Multifactorial Origin**: The blackout was not due to a single failure but a **cascade of events** involving voltage instability, system oscillations, and inadequate reactive power control.
– **Five Phases Identified**:
1. **Pre-event voltage instability** (9:00–12:00)
2. **System oscillations** (12:00–12:30)
3. **Generation losses due to overvoltage** (12:32–12:33:18)
4. **System collapse to zero voltage** (12:33:18–12:33:30)
5. **Supply restoration** (12:33:30 on April 28 to 14:36 on April 29)
– **Root Causes**:
– **Insufficient dynamic voltage control** due to limited synchronous generation and inadequate reactive power absorption.
– **Unusual oscillations** (notably at 0.6 Hz) possibly triggered by specific photovoltaic installations.
– **Overvoltage-induced disconnections** of renewable plants, leading to a self-reinforcing collapse.
– **Delayed or inadequate response** from some generators and infrastructure operators.
– **Cybersecurity**: No evidence of cyberattacks was found. However, **vulnerabilities and poor configurations** were identified in several digital systems.
#### **Restoration Efforts**
– Power was restored to **99.95% of demand by 7:00 AM on April 29**, using a strategy of **islanded grid segments** reconnected progressively.
– Support from **France and Morocco** was critical in re-energizing the grid.
#### **Recommendations**
– **Technical**: Accelerate deployment of voltage control technologies (e.g., synchronous compensators, FACTS), enforce compliance with voltage regulation standards, and improve grid observability.
– **Regulatory**: Update operational procedures, strengthen oversight of shared evacuation infrastructures, and enhance coordination with European partners.
– **Cybersecurity**: Implement NIS2 and CER directives, improve authentication, logging, and network segmentation, and expand coverage to smaller operators.
– **Market Design**: Reassess the impact of quarter-hourly market intervals and interzonal gate closure times on system stability.
—
Would you like a translated version of this summary in Spanish or a more detailed breakdown of any specific section?
What I found interesting was all the asynchronous plant was supplying the grid at fixed power factor. They were using the synchronous plant on to do the dynamic VARs control but the grid wasn’t dispatching them to do it. – Their static equipment had all already been taken out in an unsuccessful attempt to lower the voltage. The report authors don’t seem to understand capability curves of generators, but that may be an auto-translate issue of word choice.