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Power Outage Mystery: What Went Wrong in Iberia
SpainFriday, March 20, 2026
A sudden, widespread loss of electricity hit Spain and Portugal on April 28 last year, becoming the biggest blackout in Europe for over twenty years. Power was cut to many regions for up to sixteen hours.
Investigation by ENTSO‑E
The European network of electricity operators, ENTSO‑E, released a final report concluding:
- No single fault triggered the outage.
- Multiple problems aligned to create a voltage spike that destabilised power plants and transmission lines.
Key Factors
| Factor | Explanation |
|---|---|
| Thermal Plant Voltage Control | Coal, gas, and nuclear plants failed to keep voltage within grid limits. |
| Manual Voltage Regulation | Devices that should have automated response were still manually operated, slowing mitigation. |
| Mismatched Surge Protection Settings | Protective disconnect thresholds did not align with safety requirements. |
| Spain’s Broad Voltage Range | The grid operated over a wider voltage band, leaving minimal buffer before protective disconnections. |
| Cross‑Border Link Management | Interaction with French links may have altered power flows, aggravating the situation. |
| Data Gaps | Missing information from plant owners obscured early shutdown causes. |
By addressing these areas, ENTSO‑E believes the risk of a similar blackout can be significantly reduced.
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