Spain’s April blackout: Grid failure or planning flaw?

Spain’s grid operator Redeia is at the centre of a major controversy after a government report blamed its mismanagement for the country’s worst electricity blackout in recent history.

The outage, which began shortly after 12:30 PM on 28 April 2025, plunged much of Spain—and parts of Portugal—into darkness. The blackout lasted into the night, disrupting transport, mobile networks, internet services, and critical infrastructure.

In just five seconds, Spain lost 15 GW of power—around 60% of its total supply.

On 17 June, a government investigation concluded that Redeia, through its subsidiary Red Eléctrica de España (REE), had failed to maintain adequate voltage levels and miscalculated the energy mix. This reportedly triggered a chain reaction starting from the Granada substation, followed by failures at Badajoz and Seville.

Energy Minister Sara Aagesen said at a news briefing that voltage control capabilities were either misconfigured or insufficient. She noted that REE had chosen not to activate more thermal power plants during the central hours of the day, despite early warning signs of grid instability.

According to the report, many power plants did not absorb the expected reactive power, despite being paid to do so. The result was an unstable grid vulnerable to surges.

Utilities lobby Aelec, representing Iberdrola and Endesa, supported the findings, stating that REE relied on limited synchronous capacity and an uneven geographic spread of resources. This, the lobby said, left the system exposed.

Redeia has strongly denied the allegations. At a briefing on 18 June, operations chief Concha Sanchez said their internal analysis showed sufficient voltage control was planned. She argued that conventional power plants had failed in their role, particularly in controlling voltage during the incident’s initial seconds.

Sanchez highlighted that some plants disconnected despite the system voltage being within limits and noted that a critical combined-cycle plant shut down unexpectedly. A sudden spike in electricity demand from transport networks was also observed, adding to the stress.

Redeia maintains that system conditions were normal before noon and insists that another gas plant would not have changed the outcome. The company’s leadership—Chair Beatriz Corredor and CEO Roberto Garcia Merino—stated they followed all protocols and do not expect legal consequences.

Meanwhile, the government plans to propose new measures to improve voltage control and enhance Spain’s integration with the wider European grid.