Blame game breaks out over blackout in Spain and Portugal

Hello and welcome to Energy Source, coming to you today from London and Madrid.

It has been more than one month since Spain and Portugal suffered a catastrophic power cut, causing disruption to trains, businesses, schools, hospitals and communication across the Iberian peninsula. 

The electricity system collapsed just after 12.30pm Spanish time on April 28 and was restored mostly in the early hours of Tuesday morning. 

With no cause identified at the time, the days that followed were filled with speculation, including questions as to whether operators had done enough to make sure they could cope with high levels of renewable power. 

Forty-three days later, some helpful details have been put into the public domain, including this timeline from the European Network of Transmission System Operators for Electricity (Entso-e), which has set up a panel to investigate. 

It homes in on the following calamitous half-hour on Spain’s power grid (times in CET):  

• 12.03-12.07: Oscillations in power and frequency are felt on the Spanish and Portuguese power systems.

• 12.16-12.22: Inter-area oscillations on the European grid, including as far away as Latvia, dealt with through measures including reducing power flows between France and Spain. Whether these contributed to what happened next is unclear.

• 12.32.57, 12.33.16 and 12.33.17: Three generators in the south of Spain trip off, amounting to a loss of 2.2 gigawatts (roughly enough for 2mn homes).

• 12.33.18-12.33.21: Voltage increases sharply in southern Spain and then in Portugal. This sets off a “cascade” of other power stations tripping off. The frequency, which has to be balanced at all times, starts to fall. (Generators are often programmed to trip off if the frequency falls below a certain level, creating a vicious cycle.) 

• 12.33.19-12.33.22: Spain and Portugal’s power systems fall out of step with the rest of the European power grid. Automated measures to stabilise the situation kick in. But these are “unable to prevent the collapse of the Iberian power system”, Entso-e said.  

The timeline is helpful in identifying a surge in voltage as one important driver of the crisis. The tripping-off of the first three generators could have contributed to this surge, as they were no longer available to absorb reactive power.

But there remains no information about what caused the loss of generation in the first place — nor which generators they were — leaving other power system operators at a loss for how they might prevent future cuts.

Three separate generation losses at the same time is unusual and suggests a common cause, according to Janusz Bialek, an expert in power systems at Imperial College London. 

The system is also not set up to cope with so many failures at once. “Power utilities apply so-called (N-1) security criterion meaning that a trip of a single element (transmission line or a power station) should not cause problems,” he adds. In this case, there were three. 

Power systems are increasingly complex machines and there will be millions of data points to go through. But Entso-e has warned of potential delays to its investigation due to third parties’ reluctance to share data. 

“Red Eléctrica (Spain’s grid operator) recently informed us of the reluctance of the third parties to share the relevant data, which could lead to potential delays in the investigation of the Expert Panel,” it said in a letter to Spanish energy and environment minister Sara Aagesen last week. 

“The third parties cite confidentiality requirements to which they would be legally bound.”

Meanwhile, the public blame game over the blackout is becoming increasingly acrimonious as Red Eléctrica and the biggest utility companies point fingers at each other for what went wrong.

The confrontation began last month when Beatriz Corredor, chair of the parent of Red Eléctrica, declared that some large plants — using gas, nuclear or hydro power — had not done their job in helping to control voltage on the grid in the moments before the outage, as the Financial Times first reported. 

She doubled down a week later, repeating the same accusation and declaring that her team did nothing wrong.

“Our grid did not fail,” Corredor told La Vanguardia newspaper — the “our” being a possible allusion to the fact that Red Eléctrica controls the high-voltage transmission grid but the utilities operate the distribution grid that carries power to end users while also running power stations.

She added: “There was no operational failure. There was not an excess of renewables without synchronised power connected. We also know that there was sufficient inertia, there was no short circuit, no overload, and no cyber attack.”

At a conference on May 29 she said “at Red Eléctrica we don’t do experiments”, her way of rebutting a report in The Telegraph that on the day of the outage Spain was probing how far it could push its reliance on renewables.

Iberdrola, one of the world’s biggest power groups, has led the fight back in response to Corredor’s accusations against the utilities.

“We’ve been singled out from the first moment,” Mario Ruiz-Tagle, head of Iberdrola’s Spanish unit, said last month. But he declared that Red Eléctrica had been recording excess voltage in the days before the blackout and that voltage on the grid operator’s lines was above normal levels just before the collapse.

“Before, during and after the incident, [Iberdrola] always complied with the protocols and regulations established by the [energy and environment ministry] and by the system operator, Red Eléctrica, which is ultimately responsible for keeping the lights on in the country,” he said.

Speaking to the FT recently, Miguel Stilwell d’Andrade, chief executive of the major Portuguese utility EDP, avoided casting blame but added there were “lessons” to be learned, even as the root cause of the blackout has yet to be determined.  

Spain needed more interconnection with France, more electricity storage and more sophisticated technology to manage the network, he said.

“I think people have got the message and now it’s a question of making that happen.” (Rachel Millard and Barney Jopson)

Sunny side down

In a warning sign from the US, residential solar panel installer Sunnova Energy filed on Sunday for Chapter 11 bankruptcy protection, after raising the alarm over its finances in April.

It is the second company in the US sector to file for Chapter 11 this month, following Solar Mosaic. Residential solar had a difficult 2024 in many countries as rapid growth in previous years eased off and incentives were pulled back.

But in a filing in a Texas bankruptcy court, Sunnova’s chief executive Paul Matthews said more recent “tariffs and uncertainty over the nation’s commitment to incentivizing solar power generation” were also casting a shadow over the US industry.

President Donald Trump’s tariffs risk pushing up solar panel costs in the US, while industry groups warn the potential early end of certain tax credits for homeowners installing solar panels would be a huge blow.

“Every rooftop solar installation is another step towards true American energy independence,” argues the Solar Energy Industries Association.

Sunnova Energy’s failure may be a taste of more to come. (Rachel Millard)

Power Points

Energy Source is written and edited by Jamie Smyth, Martha Muir, Alexandra White, Kristina Shevory, Tom Wilson and Malcolm Moore, with support from the FT’s global team of reporters. Reach us at energy.source@ft.com and follow us on X at @FTEnergy. Catch up on past editions of the newsletter here.