The mechanics behind Spain’s mega-blackout

BRUSSELS — The long-neglected web of cables, coils and switches that keeps Europe’s lights on is finally having its moment in the limelight — for all the wrong reasons. 

Energy concerns have dominated the continent’s politics in recent years, with the European Union shunning Russian imports after Moscow invaded Ukraine and ditching fossil fuels for cleaner alternatives. 

But officials have largely focused on where that power comes from — allied or unfriendly nations; climate-friendly or planet-warming sources — rather than how electricity circulates. Europe’s power grids were usually an afterthought. 

Until Monday, that is, when a massive power outage paralyzed the Iberian Peninsula, halting trains and pushing hospitals to backup generators. On Tuesday, Spanish officials identified a freak incident in the electrical grid as the likely culprit, all but ruling out a cyberattack. 

Once the lights were back on, the blame game started in Spain, with the socialist government and the conservative opposition trading blows in a rather literal example of power politics — threatening to distract from the technical questions arising in the blackout’s aftermath.

Yet the question of what went wrong and how to stop it from happening again is vital as Europe relies increasingly on electricity — and, by extension, its power grids — in its pursuit of climate neutrality by 2050.

What’s a grid, anyway? 

Picture a network of water pipes. On either end of those pipes, some parts of the system fill up the network (think power plants) and others take from it, whether it’s a person plugging in a phone or a factory switching on its machines. 

“If we pour more water than is consumed, the pipes could burst; if we pour less, demand would not be met. This balance must be maintained continuously, 24 hours a day, 365 days a year, despite constant variations in consumption,” said Miguel de Simón Martín, a professor at the University of León’s electrical engineering department. 

That balance depends on an intricate network of substations and other elements that work like valves regulating the pressure and flow in a water distribution network. If there’s too much or too little power, operators can make corrections. Almost all of the time, this system works without a hitch in Europe. Massive blackouts are exceedingly rare. 

Why are blackouts even a thing? 

Blackouts can be wildly inconvenient and cause chaos, but they actually help keep Europe’s grids safe. 

In the same way that circuit breakers trip when we run too many electrical devices at home, sections of the bloc’s power network shut down if there’s a sudden drop or surge in the power it’s handling. If the grid is exposed to unexpectedly high voltages and currents, energy infrastructure can be damaged or even destroyed. 

The sudden blackout in Spain and Portugal happened when the Iberian grid experienced a significant power imbalance, which triggered a self-defense shutdown. Paradoxically, the fact that the lights went out is a good thing — it shows the mechanisms designed to protect the power network from serious damage are working.

What exactly happened down there? 

At 12:33 p.m. on Monday, something truly crazy happened: More than half of Spain’s power suddenly vanished. Unsurprisingly, that destabilized the grid, triggering a massive blackout. 

The grid appears to have experienced an initial, second-long power generation loss from which it swiftly recovered. But immediately after, it experienced the longer interruption that triggered the blackout, according to Red Eléctrica, Spain’s national transmission system operator (TSO). 

Power is now restored, but what caused these episodes remains unclear. Many initially feared a cyberattack, but Red Eléctrica said Tuesday that a preliminary assessment didn’t uncover any evidence of digital infiltration.

National officials are now looking at the role private companies may have played. While warning against jumping to conclusions, several experts also highlighted potential grid vulnerabilities linked to the country’s reliance on renewables. 

Can we pin this on renewables? 

Spain and Portugal are poster children of the EU’s plan to replace fossil fuels with renewable sources like solar and wind. 

According to Red Eléctrica, the problem originated in the southwestern region of Extremadura, which is home to the country’s most powerful nuclear power plant, some of its largest hydroelectric dams and numerous solar farms. 

The company’s head of system operation services, Eduardo Prieta, said Tuesday that it was “very possible that the affected generation could be solar.” In an annual report published in February, Red Eléctrica’s parent company warned the increased share of renewable energy in the system could result in “significant” disruptions. 

Despite that, experts and EU officials on Tuesday went out of their way not to blame renewables for the incident and declined to speculate on the matter. That didn’t stop Spain’s far-right party from seizing on the blackout to intensify its campaign against the government’s energy transition plans. 

Why did it spill over into Portugal? And why was the rest of Europe not affected? 

The Iberian Peninsula has a highly integrated power grid that allows Spain and Portugal to routinely exchange electricity. Those links usually make grids more stable, but on Monday it led to the collapse of the electricity supply in both countries.

Although the Iberian Peninsula is somewhat isolated, it maintains a few cross-border links with France. Monday’s power crisis didn’t spread far north of the Pyrenees because the bloc’s grid is designed to protect itself from these situations, and the moment the Spanish grid became unstable, it was automatically disconnected from the French network.

So this kind of thing can’t happen elsewhere in Europe? 

The EU’s energy grid is designed to respond quickly to episodes of this kind, but that doesn’t mean that it’s immune to blackouts.

In 2006, millions of people in Germany, France, Italy, Belgium and Spain lost power after a power line was disconnected to facilitate a cruise ship’s voyage on the Ems River. And just last year, extreme heat caused a blackout that affected Bosnia and Herzegovina, Albania, Montenegro and parts of Croatia.

One key way in which Europe avoids power outages is by linking up neighboring countries’ power grids. “Having an interconnected system is good for everyone,” said a senior EU official who explained that connections make it easier to manage dramatic power supply changes. That helps keep the grid balanced and prevents blackouts.

It’s worth emphasizing that those connections do not increase the possibility of a grid collapse spreading across countries. As the shut-off of the link between Spain and France showed Monday, there are automatic processes in place to prevent cascading blackouts. 

Speaking of, are we taking good care of our precious grids? 

While most people take their grids for granted, policymakers are keenly aware of the challenges and have been working on them for years, issuing tons of bland-sounding legislation that has helped Europe develop one of the world’s most extensive power networks. 

But there are still serious network weaknesses: Governments have generally been slow to invest in grids, which are out of sight and out of mind for most citizens, and the bloc’s countries have some seriously old infrastructure. Climate change fallout, particularly the extreme heat becoming more frequent in Europe, also poses a particular threat to aging grids.

The European Commission estimates that around €584 billion in investments are needed this decade to update and expand the bloc’s power grids.

Wait, why do we need to expand our grids? 

Electricity use is surging — not in some distant future, but right now. The European Commission expects EU power demand to rise by around 60 percent by 2030 compared to 2023, and the bloc’s grids need to be beefed up in order to cope. 

There are a few reasons for the increased demand. A key factor is the EU’s energy transition, which is replacing polluting fossil fuels with climate-friendly alternatives. Think swapping traditional cars for electric vehicles or gas boilers for heat pumps. 

There’s also the fact that electricity-hungry sectors, such as artificial intelligence, are on the rise. And as the planet warms, more and more people will turn to air conditioning to keep cool, including in Europe. 

“We need to discuss how we are going to deal with a situation like this,” given that soon “every part of the economy will be electrified,” said one EU diplomat. “Imagine in 20 years [we] have a total blackout … You cannot get your car, go to your work.” 

And what’s next in Spain? 

EU law requires incidents involving Europe’s grids to be thoroughly investigated.

Spain has to issue a technical report explaining what happened within three months. A larger independent probe conducted by European experts has to issue its own findings within six months.

Those investigations will be instrumental in making the EU’s electricity grid stronger in the long term. A senior Commission official said the report detailing a 2003 Swiss incident that caused a massive blackout in Italy shaped new EU protocols. Those measures, the official added, helped EU countries avoid a major blackout between 2013 and this past Monday.

While the experts work out what went down, expect plenty of political mud-slinging about who or what is to blame.