Spain’s Electrical Blackout: A Technical Breakdown of Recent Failures
Nearly two months after the blackout that severed Spain and Portugal from the European power grid, the Spanish Government has released a technical report highlighting a specific issue: the lack of voltage control during critical moments, particularly in renewable parks.
Is it possible? As noted by energy engineer Xavier Cugat on social media, the debate around voltage control in renewable installations is not merely a technical one: technologies already exist to tackle this issue. One notable example is SMA’s ‘Q at Night’ system, which allows solar plants to provide reactive power even during the night.
The idea is straightforward: if a solar plant can continue to support the grid even without sunlight, part of the stability issue can be mitigated. While this does not directly address the lack of inertia , it does enhance voltage support and improves the system’s resilience.
Reactive Power. The principle is simple yet effective. SMA photovoltaic inverters , equipped with the Q at Night function, remain connected to the grid even when they are not generating active energy (i.e., during nighttime). This enables them to inject or absorb reactive power as needed, helping maintain voltage levels within acceptable margins.
In High Penetration Scenarios. This type of energy is crucial for preventing voltage instability. In specific cases, it is essential for a grid with a low presence of conventional power plants. Although it does not contribute inertia, it allows plants to support voltage balance and remain connected during critical events rather than disconnecting preventively.
So, what about inertia? Here is where clarification is necessary. The government report has made it clear that the blackout was not caused by a frequency drop but rather by a cascade of overvoltages . Even in scenarios with higher inertia, disconnections due to overvoltage would still have occurred, according to the report. Consequently, a lack of inertia was not the direct cause of the blackout; rather, the blackout led to a frequency drop.
During the blackout, various plants preemptively disconnected upon detecting overvoltages. The problem is that, according to the report, many of these disconnections occurred before the maximum permissible limits set by regulations were reached. In other words: they did not adequately respond to grid conditions .
A System Not Adapted to Its Own Transition. The problem appears to be structural: the electrical grid has not evolved at the same pace as the mass deployment of renewable energy sources. With 82% of clean generation and the fewest operational synchronous plants throughout the year, the system faced an explosive cocktail: extensive distributed generation, minimal centralized control, and limited responsiveness to critical events. In just 12 seconds, the entire Iberian system disconnected from the rest of Europe.
A Transition Without a Safety Net. The blackout was a symptom, not an anomaly. Spain leads the renewable transition, but without a prepared grid , every advance becomes a vulnerability. Voltage control, incident response, and maintaining stability without large rotating machines pose significant challenges in the new energy paradigm.
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Xataka | 49 days after the blackout, the government has released the official report. Contrary to expectations, it identifies a culprit.