The blackout that left much of the Iberian Peninsula and parts of southern France without electricity on April 28 has raised alarm bells about the vulnerability of the European electricity system. Beyond the causes—still under investigation—the incident highlights the urgent need to strengthen electrical infrastructure and accelerate the implementation of bulk energy storage systems (BESS), which is key to ensuring security in a context of transition to renewable sources.

The magnitude of the event creates uncertainty about the possibility of a repeat in other parts of the continent.

“Other European countries are at risk. First, because the entire European Union electricity grid is interconnected and interdependent. Second, because with the energy transition, we are losing the physical inertia of the grid, which increases the need for synthetic inertia from battery storage systems,” emphasizes Pablo Fernández Oliver, Energy Storage Sales Engineer Lead EMEA at Fluence, in an interview with Strategic Energy Europe.

While authorities work to clarify the source of the outage, official reports indicate that the outage began at 12:32 p.m., immediately affecting critical infrastructure and leaving millions of users without power. Red Eléctrica Spain confirmed that full service restoration took between 6 and 10 hours, with priority given to hospitals and transportation systems.

“The restoration process requires a meticulous and gradual approach to safely reactivate each section of the grid,” explains Nayeem Hossain, an engineer specializing in renewable energy, in an interview with this media outlet.

He also emphasizes that “given the magnitude of the outage and the high penetration of renewable energy, special attention is required to maintain stability during the resynchronization of energy sources.” According to Hossain, this episode represents a key test for the smart infrastructure recently deployed by Iberdrola in its distribution system.

At the same time, the economic impact of the blackout is starting to emerge. While final figures are still being assessed, preliminary estimates suggest significant losses, particularly in the industrial and service sectors. In this context, Juan Zurbarán, a renewable energy consultant, raises a key question for the business community: “If it turns out to be a human or technical error… will there be any compensation for the affected companies?“

Causes under investigation and the latent risk of electrical interconnections

The exact cause of the blackout remains unclear, although the possibility of a cyberattack stands out among the hypotheses being considered, raising particular concerns about the security of Europe’s critical infrastructure.

“The causes are still being studied. It’s better not to speculate,” declared Prime Minister Pedro Sánchez in an institutional appearance just after 6:00 p.m., warning that “critical hours” were approaching.

Grid imbalances can be caused by multiple factors, from failures at large power plants and line congestion to the loss of substations or key connections. “Blackouts occur due to grid imbalances, and for this to happen, several elements must fail simultaneously,” explains Pablo Fernández Oliver.

The Fluence executive points out that, although the root cause is still unknown, these types of events could be avoided with the proper integration of energy storage systems. Initial reports point to a failure in the electrical interconnection with France, possibly exacerbated by the fires in the south of the country, which have affected strategic infrastructure.

However, the threat of a cyberattack has not been ruled out. “If the cyberattack theory is confirmed, what will be the next steps for Spain, Portugal, and the EU?” Juan Zurbarán said in a dialogue with Strategic Energy Europe, highlighting the geopolitical dimension of the incident.

European electricity interconnections, designed to strengthen energy security through cross-border cooperation, demonstrated their vulnerability in this case. “Interconnections are a double-edged sword: they allow for mutual aid in times of scarcity, but they can also rapidly propagate failures,” warns Nayeem Hossain. The simultaneous blackout in three countries highlights the urgent need to strengthen resilience and improve operational coordination at the European level.

Despite the risks, Hossain emphasizes that proper management can contain the impact of future incidents. “A swift decision and the use of modern technologies, such as the automatic disconnection of faulty lines, can minimize the consequences.”

Furthermore, it proposes concrete measures: “At the European level, improving the resilience of interconnections, harmonizing grid codes, sharing operational data in real time, and coordinating emergency response plans will be key to preventing or better managing large-scale disruptions.”

Energy Storage as a Strategic Solution

The event highlighted the importance of battery energy storage systems (BESS) in avoiding this type of crisis. “Battery energy storage systems can react to these imbalances in a matter of milliseconds, thus avoiding national blackouts,” says Fernández Oliver.

Spain has made progress in bidding for storage projects with government subsidies, but Fernández Oliver warns that bureaucratic agility will be crucial: “A battery storage system can be built in less than 11 months, but permitting is necessary before that happens.”

Consultant Zurbarán agrees that this situation can act as a catalyst for the market: “Could this situation accelerate the energy storage market?” he asks.

For his part, Hossain points out that these backup technologies are “essential” for recovery after a blackout of this magnitude. He also points out that black-start power plants, which can begin operating without external power, are crucial for restarting the grid.

Electricity Grids and Renewables: The Challenge of Resilience

With the increasing penetration of renewable energy, European grids face new challenges. Spain, which recently managed to operate for a full day using renewables alone, is now facing the consequences of this variability and decentralization, which can complicate grid management, especially during unexpected failures like this one.

“This blackout highlights the challenges of managing systems with a high presence of renewables. Advanced forecasting and fast-acting control systems are essential to maintaining resilience,” Hossain emphasizes.

Fernández Oliver adds that, with the energy transition, the physical inertia of traditional grids is being lost, increasing the need for synthetic inertia provided by storage: “You can see how German TSOs are building large grid-connected assets to address these types of imbalances.”

Outlook and Future Measures

While official reports on the root cause of the blackout are awaited, both governments and grid operators are already working to strengthen the electrical infrastructure. “I am confident that measures will be taken to prevent these events from occurring. The government is taking action to ensure energy security and, at the same time, advance the transition,” says Fernández Oliver.

For his part, Hossain highlights the role of smart metering technology, such as that implemented by Iberdrola: “approximately 11 million customers now benefit from smart meters with real-time monitoring. These systems have proven very effective, especially in managing the blackout during the recent floods in Valencia earlier this year.”

“It is difficult to specify anything now, but a comprehensive solution will be possible once the root cause is properly identified,” he adds.
The consensus among experts is clear: Europe must accelerate investments in storage, strengthen cross-border coordination, and modernize its networks to meet the challenges of an increasingly renewable and decentralized system.