The five seconds that plunged Spain into darkness

The incident is a fact, and a major one at that: an entire afternoon without electricity in Europe’s fourth-largest economy. But the “black box” is still missing. Technicians at Red Eléctrica de España (REE), the grid operator, are working against the clock to figure out what led to the worst-case scenario: a system completely devoid of energy, a nightmare situation that several generations of engineers had only encountered in simulations.

First, the facts. Shortly after noon on Monday, and in a matter of seconds, something suddenly caused the frequency to drop below the usual 50 hertz. The interconnection with France automatically tripped to prevent further damage in the form of a massive contagion in the rest of Europe. Some 15 gigawatts (GW) of electricity generation, nearly 60% of energy in use at the time, were lost, and millions of people in Spain and Portugal were left without power across the Iberian Peninsula. This is the known sequence of events; the key now is to understand what caused this sudden drop in power, leading to the largest blackout in recent European history. Pending an analysis of thousands of data records, the preliminary theory put forward by REE on Tuesday is that an incident at two photovoltaic plants in the southwest of the peninsula could be responsible. Less than 24 hours later, REE President Beatriz Corredor, clarified, however, that “it is not right to link the incident to renewable energy.”

Everything that happens in the electrical system is recorded. “So, with complete certainty, we’ll be able to know where and what caused the blackout,” underscores Luis Atienza, a former president of REE. Just like the other specialists consulted for this article, Atienza expressed surprise at the failure to activate of the automatic mechanisms that would normally have contained the outage and confined it to a specific area, instead of impacting nearly the entire peninsula. It will take days, he says, before the reason for this is known.

“The failure of a photovoltaic plant, however large, doesn’t seem likely to be the cause of the collapse of the entire electricity system,” says Pedro Fresco, general director of the Valencia Energy Sector Association and former general director of Ecological Transition for that eastern region. “Nor is it true that there weren’t enough synchronous sources at that time: there was nuclear, a lot of hydropower, some solar thermal and combined cycle power, and even cogeneration, coal, and renewable waste… In fact, there was more synchronous power than at other times.”

The great blackout did not turn out to be as some feared. During the 2022 energy crisis, the prophets of doom sounded their trumpets for months, projecting a drop in supply that never materialized. Generation, they claimed, would not be enough, and consumers would be unable to turn on the lights, run the washing machine, or charge their cell phones. The reality was different: at midday on Monday, demand was neither particularly high nor supply at its lowest (on the contrary, solar was operating at almost full capacity, covering almost 60% of consumption, with water and wind together providing another 20%, and four nuclear reactors operating). It was barely necessary to resort to combined cycle natural gas-fired power stations, whose profitability has long been questioned, but which remain essential during peak consumption periods and when there is no sun or wind.

“Until the origin of the problem is 100% clear, fixing it is going to be difficult: for now, it’s as if a plane had crashed and we didn’t have access to the black box,” compares engineer Javier Revuelta, head of the electricity practice at the Swedish consulting firm Afry. “The first thing to determine is whether the problem was due to low synchronous power or if it was something else,” adds Óscar Barrero, the partner responsible for energy at PwC. “Most likely, it was a combination of both.” Industry experts are greatly surprised at the inability to isolate the blackout to a specific area, which forced the system to be re-energized from scratch.

The benefits of renewables, which make the Spanish wholesale market one of the cheapest and cleanest in Europe, remain clear. Despite the short but brutal impact of the blackout on businesses and individuals, it doesn’t seem likely that a debate will be opened on a change of model, especially given that the competitiveness companies gain as a result is one of the factors that explain the improved performance of Spanish GDP compared to its European counterparts. However, some voices, such as those of the consultants Barrero and Revuelta, are calling for adjustments. “The penetration of wind and, above all, solar power, when it is massive, creates challenges in the management of the electricity system. Synchronous backup power is needed, not only during times of high demand, but also when there is surplus electricity,” argues the former. “Operating criteria will have to be reviewed to be even more cautious: it’s worth conducting an in-depth analysis of how solar and wind generators have performed, and they will likely need to demand more technical performance. Perhaps by requiring or incentivizing them to incorporate batteries to mitigate frequency drops in milliseconds,” explains the second, who worked for several years at REE.

The fact that the Iberian Peninsula is, in practice, an energy island hasn’t helped. Interconnections with the rest of the continent remain far lower than the European Commission demands. And it’s not because Spain doesn’t want them, but because France has been resisting them for years. Some experts attribute this attitude to France’s attempt to protect its powerful nuclear sector from the competition posed by the much cheaper Spanish solar power. Laying more cables with the neighboring country—one is already under construction in the Bay of Biscay, but it still won’t be enough to meet the European Commission’s target—could also be part of the solution. The Brussels report on what happened could put additional pressure on France to end its reluctance.

Another weakness to be addressed is Spain’s delay in the mass deployment of batteries, which has already taken place in Germany, Australia and the U.S. state of California. Storage, in the form of large-scale batteries or pumped hydroelectric storage, would mitigate the problem, making the system more robust. “Batteries and strong interconnections are the best antidotes to blackouts. We need to install more of the former, which make photovoltaic and wind power synchronous, and improve the latter,” urges Fresco.

The outage has fueled a debate that, like so many others, long ago leaped from the technical to the cultural war: the future of the five nuclear power plants still operating in Spain, with a timeline that calls for their closure by 2035. “In this case, it’s not so much a ‘nuclear yes or no’ debate, but rather whether synchronous generation, which also includes other technologies such as combined cycles and hydroelectric power, contributes to mitigating potential blackouts,” Revuelta concludes. “I don’t know if it makes much sense for the prime minister to have spoken out so strongly so soon,” he notes, referring to Sánchez’s recent criticism of those who have linked the incident to the lack of nuclear power plants. The government’s initial analyses suggest that the presence of nuclear power in the mix did not make the system more resilient, and even delayed normalization by making it necessary to send energy to maintain them.

Agile response

The most positive interpretation of the nightmare is that power returned relatively quickly. Monday afternoon dragged on, yes, but by nightfall, most of Spain and Portugal had power back. A few hours, for an incident of this magnitude, is a short time. “The restoration of service during this blackout has been impeccable,” says Atienza. “It’s worth comparing it with the blackouts in Italy or northeastern U.S., both in 2003.” It took days to restore power. In the Texas blackout of February 2021, it took more than two weeks.

Could a blackout of this magnitude happen again? “Zero risk doesn’t exist and never will, but the probability of it happening is lower today than on Monday because everyone will be treading carefully,” Barrero suggests. As with plane crashes, the emergence of the black box should help us learn from what happened—not only in Spain but also around the world—and thus try to prevent it from happening again. “It’s an extremely unlikely event. I don’t think we’ll see one like this again in our lifetime,” Fresco concludes.

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