The IEA considers the power outage of 28 April in the Iberian Peninsula to be indicative that electrical security depends not only on generation, but also on the quality of grid operation and the behavior of all connected assets, as the incident was caused by a “rapid succession of technical faults”, including false interruptions of generators, even though voltage levels have not yet exceeded established thresholds.
The agency notes in the appendix to its “World Energy Outlook 2025” report, which includes the conclusions of ENTSO-E, the European Network of Electricity Transmission System Managers, that in the minutes before the blackout, the electrical system became unstable with unusual fluctuations in voltage and power flow: “The event was triggered by a rapid series of technical failures.”
“This instability was followed by a sharp increase in voltage, as protection systems wrongly disconnected generators that were absorbing reactive power, even though voltage levels had not yet exceeded the thresholds set by regulations,” the IEA explained, according to Europe Press.
Thus, as more plants went offline, voltage increased, leading to “a cascade of additional outages,” while hundreds of megawatts of smaller distributed sources went offline unexpectedly, making it more difficult for system operators to respond.
For the IEA, the April 28 blackout “demonstrates that electrical security in modern systems depends not only on generation, but also on the quality of grid operation and the behavior of all connected assets,” highlighting the need for binding standards that require all generators to support the system during emergencies and disconnect “only if clearly defined thresholds are exceeded.”
In this sense, he considers that preparedness remains essential and highlights that the rapid restoration of electricity supply in the Iberian Peninsula was possible thanks to the strong interconnection with neighboring countries, robust emergency protocols and available black start capabilities, which is why he notes that “preserving and strengthening these capabilities is crucial.”
Likewise, it states that the international attention sparked by the blackouts in Iberia provides the opportunity to review some common elements of the security and resilience of electricity supply as energy systems evolve.
Thus, although electricity systems and market structures vary from country to country, the IEA identifies “four cornerstones” that are essential in all cases, including, above all, a strong grid infrastructure, which includes robust grids and regional interconnections, as they form the basis for safe operation.
Second, the IEA considers electricity system resilience essential to balance supply and demand, including demand response, storage and maintenance of dispatchable generation, as well as measures to ensure markets value these services appropriately.
In addition, technical solutions, such as synchronous concentrators or batteries equipped with grid-forming inverters, are needed to support system stability as the generation matrix evolves.
Finally, he considers it necessary to adapt operational frameworks as electricity systems transform, updating grid codes, reserve requirements, balancing mechanisms and regulatory structures to keep pace with new challenges and technologies.
“The economic costs of power outages are very high,” the IEA concludes, adding that examples such as this year’s power outages in Chile in February, and in April in the Iberian Peninsula, “remind us how power outages can have a domino effect and affect millions of people.” So, as the proportion of electricity in final consumption increases and the complexity of electrical systems increases, “security of electricity supply becomes increasingly important.”
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