Are we prepared for the next blackout in Spain?

At 12:33 p.m. on April 28, 2025, Spain experienced an unprecedented event in its history: a massive blackout that left more than 50 million people without electricity across the Iberian Peninsula, also affecting Portugal and parts of southern France. 

In just five seconds, 15 gigawatts (GW) of electricity generation—60% of the demand at that moment—disappeared from the grid, triggering a chain reaction that paralyzed key infrastructure such as telecommunications and rail transport. It also disrupted water supply in some regions and caused widespread economic disruption. The recovery was gradual and, although 99.95% of the supply was restored within the next 24 hours, the impact of the event left many lessons. 

In recent hours, a new trend has emerged in some media outlets, with headlines claiming that artificial intelligence has predicted another blackout in Spain this summer. Although the claim has no technical or scientific basis and originates from queries made to ChatGPT and other generative AI models, it does reflect a certain level of public distrust. A recent survey by Sigma Dos also revealed that an overwhelming majority of the population believes another blackout could happen again. 

However, the question is not whether there will be another blackout or when, but rather whether we will be prepared if it does happen—and how we can avoid an event of the same magnitude. Based on what we know so far, some useful lessons can be drawn. 

A sudden disconnection and a vulnerable system

Although the exact causes of the blackout are still under investigation by Red Eléctrica and the Spanish government, initial technical analyses already provide insight into some of the dynamics that led to the collapse. 

The power grid requires that the energy entering the system from power plants and the energy consumed by demand remain balanced within very narrow margins. The electrical frequency, which must remain close to 50 hertz (Hz), dropped sharply when 15 GW suddenly vanished from the system. 

“We know that to prevent what happened next, other generators would have had to immediately compensate for the loss. We also know that these are, ultimately, machines that cannot deliver more power or speed than they were designed for,” explained Enric R. Bartlett, professor of public law at Esade specializing in the energy market, in an article for El Periódico. 

As Bartlett explains, the electrical system works like a tandem of cyclists: all generators must “pedal” at the same pace. If one fails, the others must immediately compensate. But if they can’t do so without exceeding their own limits, they disconnect to protect themselves—triggering a domino effect. That is exactly what happened on April 28. 

Lessons for the next blackout

“Before proposing what to do to avoid a repeat of the event, we need to wait until the exact causes are known,” warns Bartlett. However, he also points to a number of actions that don’t require waiting. Among them: building a more interconnected and digitized grid that can incorporate the necessary energy more quickly in case of a sudden loss. Some of these actions depend more on regulatory changes than technical ones. 

Spain has made significant progress in integrating renewable energies, meeting the targets of the National Integrated Energy and Climate Plan (PNIEC). However, the development of key infrastructure such as energy storage—through batteries and pumped hydro, which could have quickly compensated for the lost power—and the power grid has not kept pace. The latter is particularly concerning, as the network deficit also hinders storage development and limits demand growth. 

That said, the legal framework needs updating, as it currently sets an investment cap based on GDP that is insufficient to meet the grid’s modernization needs. “The investment planned under the PNIEC is 2.4 times higher than what the current legal cap allows. The cap must be aligned with the forecasted needs, not the other way around,” Bartlett emphasizes. To prevent the increased investment from pushing up costs for consumers, Bartlett calls for investment in areas where new consumption generates offsetting revenue—such as EV charging stations and industries looking to electrify. 

It would also be necessary to revise regulatory limits that artificially reduce the operational capacity of cables, sometimes by as much as 50%. “It’s like having a pipe that can handle 100 liters per second but only letting 50 through,” he notes. Planning cycles should also be shortened from six to three years, as in the telecommunications sector, and procedures for implementing changes should be streamlined. 

Another important point would be to make private grids available for public use (with proper compensation), including the thousands of kilometers of underutilized evacuation lines from renewable plants. “An industry just 50 meters from such a line would currently have to pay to lay several kilometers of cable—potentially many—just to reach the nearest public grid substation,” writes Bartlett. 

What was the cost of the blackout?

During the hours when over 50 million people were without electricity, there were at least five deaths linked to the circumstances of the blackout, with other cases still under investigation. Common causes included the shutdown of home ventilators, asphyxiation from using combustion generators, and even fires started by candles. 

Economic estimates of the blackout’s cost vary widely. Initially, the Spanish business association CEOE estimated the cost at €1.6 billion. More recently, the minister of economy lowered the maximum impact to €800 million in an economy that has maintained its growth forecasts despite the tariff war initiated by Trump. 

Manuel Hidalgo, Research Fellow at EsadeEcPol and professor at Pablo de Olavide University, explained in Cinco Días the difficulty of estimating the number due to the sectoral heterogeneity during the blackout. “We must first understand that this is an estimate of a figure whose real value is impossible to know with precision,” he states. 

On the one hand, many activities continued or even peaked, such as taxi services and non-electric urban transport. However, industries where the assembly line must run at full capacity suffered more severe losses. 

Will we be ready?

In any case, the great April blackout was a turning point. Despite its limited duration, it revealed that the Spanish electricity system is vulnerable and in need of a major upgrade. While waiting for all the technical details is sensible, some of the necessary measures are already clear. The challenge is not only technical; regulatory aspects also matter, as they must enable swift implementation of changes. The question is not whether there will be another blackout and when, but whether we will be better prepared if it happens.