Extracted/ English Version - Spring 2025
International readers : this post is for you. French-speaking subscribers, we advise that you switch to the French version: https://exfiltrees.substack.com/p/exfiltrees-printemps-2025
IN-DEPTH💡: The Power Outage Gambit
By Carole
Monday, April 28th, 9:02 a.m., Aveiro Station—a charming town an hour south of Porto. The day before, I had run my first half-marathon here, beneath a bright sun and in a festive, family atmosphere. This morning, however, my smile has faded: the station is nearly deserted, apparently due to a railway workers’ strike. After a lengthy internal debate (buses fully booked until 3 p.m., or a €35 taxi and a far larger carbon footprint?), I eventually make it to Coimbra by 11, drop my suitcase at my host’s for the night, and set out to enjoy what’s left of the day. Tomorrow, Lisbon awaits!
The university quarter is quiet. I stop at a modest canteen for lunch. There is a buffet, but I am told there is a power cut and only regulars are being served. Odd. I resign myself to the day’s misfortunes. Hunger growing, I wander into a café almost at random—my phone, unhelpfully, has no signal. The terrace is sunlit, and there is one seat left: perfect.
“Omelette? Unless you want them raw, we’re not serving eggs. Hummus and crudités? That we can do. And our drinks are still cold… for now.” I learn that the outage is widespread. My German table neighbours inform me that it is not just the city, but all of Portugal and Spain, and the cause is unknown. Possibly a cyberattack. As if that were not enough: “The news says they don’t know when power will be restored. It could be two or three days.”
After a few seconds of disbelief, my mind begins to race: no solar charger for my phone, no headlamp, some cash (thankfully), but I need a code to enter my guesthouse—if I can even find my way back! I keep calm, buy university tour tickets online during a brief window of network coverage, and return to the guesthouse after my visit. My host assures me she won’t let her guests to sacrifice her cat, that she can feed us all thanks to her gas stove, and wishes me luck. Fortunately, the door code had a battery, and she lent me a city map. Thus equipped, I set out again, wandering through parks and crossing streets gingerly, now devoid of traffic lights.
The city has a Sunday air: people are outside, lounging in groups on the grass. Strikingly, they are talking to each other. Aside from a few small shops and ice-cream parlours, most businesses close—unable to take card payments or keep the lights on. In local corner shops, merchants jot down the names and amounts owed by regulars without cash.
My phone battery is dwindling, its torch indispensable for bathroom trips, so I ration its use. Above all, I must have enough left to show my bus ticket the next morning! Passing a fado club, I book a ticket for 8 p.m.; they promise a candlelit performance. A few minutes before the show, the rumour spreads: the power is back!
The return of power brought relief, but I couldn’t help noticing how calm and composed everyone seemed… What if it really had lasted three days? What exactly happened that day, and could it happen again—somewhere else, for even longer? In the first hours after the blackout, I read plenty of speculation: was it all the fault of renewables?
When the Power Goes Out 🪫
A Revealer of Our Vulnerabilities
Let’s start with the little things: this episode was a sharp reminder that our mobile phones do everything for us—we rely on them to light our way, navigate, pay, entertain ourselves, and organize our lives. More broadly, our daily routines depend on electricity, which will only become more essential as we phase out combustion vehicles—a positive step for the climate.
Yet while my own experience was relatively mild, it’s important to remember that the outage resulted in at least seven deaths (due to halted respiratory assistance and carbon monoxide poisoning from diesel generators), and thousands were trapped in elevators, trains, and subways—especially in Madrid, where the blackout lasted nearly 24 hours.
We’ve grown so accustomed to convenience that many people no longer keep the bare essentials at home to cope with such disruptions—an issue likely to recur, especially during extreme weather events. At the very least, everyone should have candles, flashlights, a battery-powered (or solar-charged) radio, some water and food reserves, and cash on hand. Even better: neighbors whose first names you actually know.
If the Blackout Had Lasted Days…🫣
Had Iberian grid operators, aided by French and Moroccan interconnections, not managed to restore power within a few hours that day—a feat known as a “black start”—the outage could have dragged on far longer. In France, after the 1999 storm, some households waited 19 days for electricity to return. Even a few hours were enough for some Portuguese hospitals to experience water shortages as pumps failed.
Once an outage stretches beyond 24 hours, it is not just electricity that is in short supply—water, a far more vital resource, quickly becomes scarce. If backup fuel stocks run low, hospital generators and other critical infrastructure, such as communications, are also at risk of shutting down. In short, the country can find itself in a state of natural disaster, potentially on a national scale. To avoid such scenarios becoming routine, it is high time to learn from experience.
Are Renewables to Blame?🧐
The recently published investigative report attributes the incident to a power surge with “multifactorial causes,” citing human error among the contributing factors. Spain’s grid operator, REE—criticised for having implemented an insufficiently robust control system on the day in question—has sought to deflect blame, pointing instead to operators who, it claims, failed to meet their obligations by disconnecting from the grid to safeguard their own installations. Shortly before the outage, two major “frequency drops” were observed on the grid, signaling a significant imbalance between supply and demand. This led to a sudden loss of about 15 GW of generation—too severe for the French grid to compensate, prompting its disconnection to avoid further contagion. At the time, wind and solar made up 70% of supply (a common occurrence in 2024), and critics of renewables were quick to point the finger.
However, a deeper look reveals a more complex picture. To meet its decarbonization targets, Europe must dramatically accelerate electrification—from 23% of end uses today to 50–60% by 2050. Massive investments in renewables are straining grid stability, and operators are far from ready. There is currently three times the grid connection capacity in the pipeline than is needed to meet 2030 decarbonization goals, underscoring the urgent need for storage, flexibility, and interconnections.
Another challenge is the lack of visibility on Spain’s rooftop solar: Bloomberg estimates up to 10 GW of self-consumption capacity, about a third of the solar officially counted (and roughly 10% of national capacity), making it harder to balance supply and demand.1
European grid operators have already warned in annual reports that the system will remain fragile if the growth of non-dispatchable sources like wind and solar continues without reinforcing the grid—especially through “grid forming” technologies that create synthetic inertia via storage or rotating machines. Like storage, grid forming is no silver bullet: it has only been tested at scale in small, isolated systems like Hawaii or parts of Australia, not across a region as large as the Iberian Peninsula.
So who will fund these additional investments? For now, renewable energy developers are not required to contribute, meaning costs are either borne by consumers or postponed. The 2019 decision to phase out nuclear power (about 20% of Spain’s mix) by 2035 will only make the challenge more acute.
Could This Happen Elsewhere in Europe?
In France, the “islanding” capability of its nuclear power plants makes grid recovery after a blackout significantly easier. Unlike Spanish reactors, which shut down entirely and switch to diesel generators during such incidents, French nuclear plants continue to operate at 30% capacity, powering themselves. In the event of a blackout, only hydropower, fossil-fuel plants (gas, coal), and such self-sustaining nuclear stations can support a restart.
France enjoys another advantage: with more neighbouring countries, it can stabilise its supply more rapidly. During the Spanish outage, Italy and the UK provided France with an extra 1.5 GW, which it was able to relay onward to Spain.
Consider Europe’s most advanced neighbours in the renewables transition: Norway boasts a power mix that is 98.5% renewable—91% dispatchable hydropower and 9% wind. Denmark, however, leads in non-dispatchable renewables, with 88% renewables in its 2024 mix: 67% wind and solar, 21% biofuels and waste, the remainder coal and gas.
What underpins Denmark’s current grid resilience? Not storage capacity (where Germany and Italy are the frontrunners), but rather robust interconnections with Norway, Sweden, and Germany, as well as massive investments in synchronous condensers and other inertia-providing technologies. In Denmark, developers are also more frequently required to contribute to these investments.
Though it will be several months before the investigation into the blackout’s origins concludes, one issue cannot be swept under the rug: the urgent need for investment in the grid to accommodate ever-higher shares of intermittent, non-dispatchable renewables.
And even if the days are long, don’t wait for Valentine’s Day to stock up on candles.
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Which allowed the University of Almería, powered by its own solar panels, to island itself from the grid and resume operations after just ten seconds of blackout…
Sources:
https://bonpote.com/black-out-electrique-en-espagne-que-sait-on-reellement-apres-3-jours-de-panne/
https://thebreakthrough.org/issues/energy/its-okay-to-notice-when-solar-and-wind-fail