· 8 min read
Last week, a major power outage hit Spain and Portugal, leaving millions without electricity. Mobile towers and traffic lights stopped functioning. As did ATMs, contactless payment systems, and trains. Petrol stations closed. All we take for granted stopped, people couldn’t move around, make payments or communicate. I certainly would not have liked to be one of the hundreds of people left in darkness and out of contact with the outside world stranded in lifts when the power failed, the stuff of nightmares.
While the scale of the Iberian blackout was striking, major grid failures happen about once a year somewhere in the world. What causes them? And what did (and didn’t) happen in this case? What can we learn from this one and why does X say it was the fault of either the Russians or renewables?
What is the grid?
If electricity is the lifeblood of society, then the grid is its circulatory system. High-voltage transmission lines (the arteries) transport electricity rapidly from points of generation to substations. There, the voltage is stepped down and distributed via lower-voltage cables (the veins) to homes and workplaces. Step down is important as plugging a HV line into your house would be like trying to take a drink from a fire hose. Keeping the system balanced is a constant, highly complex task which involves many more people physically pressing buttons and flicking switches than you may imagine.
How do grid failures happen?
Like the human body, the grid needs regular care. But even a healthy system can be pushed past its limits by external shocks. For example, the overhead cables you may see from your window rely on the air as an insulator to keep electricity safely flowing through the wires. In extreme heat, metal wires expand and sag. If the air gap narrows too much, electrical arcing can occur and the line short circuits.
When failures happen, systems shut down the affected line. But now that electricity must travel along other routes, which then become more heavily loaded. Not an issue for a single cable but if an area is impacted and not managed precisely, this can cascade, one line overloads another, which trips another, and soon an entire region is offline. It’s a domino effect that can unfold in minutes.
Wasn’t this caused by renewables or a cyberattack?
In the immediate aftermath, Spanish and Portuguese officials rightly cautioned against speculation. Even a week later they still aren’t clear, which frankly isn’t a huge surprise. An event of this scale will have many interrelated causes that take time to unpick. Unfortunately, the silence was quickly filled with misinformation and rumours. Claims of cyberattacks and the unreliability of renewables gained traction online.
I’ll dig into renewables in detail later but first let’s be clear, the grid does not care how a kilowatt of electricity is generated. A unit from a wind turbine is indistinguishable from one generated by gas or nuclear power. The real challenge is maintaining balance between supply and demand. If solar output dips, gas plants can be ramped up. If wind generation exceeds demand, turbines can be curtailed. That’s grid management 101. Shocks happen, failures arise when the management system does not adapt effectively in real-time.
As for cyberattacks, while a sufficiently sophisticated actor could, in theory, interfere with grid protections, this would require advanced coordination and access. No such evidence has emerged so far. With that said, even if the chances of a hacker having caused the blackout are small the implications are huge so a full investigation of the possibility (however remote) by the relevant authorities is entirely appropriate.
So what actually happened?
The precise cause of the blackout remains under investigation. And as mentioned above that should not surprise us. Grid collapses of this nature are rarely the result of a single failure. More often, they are multifaceted events driven by a complex mix of weather or atmospheric extremes, network fragility, and cross-border or interregional grid dynamics.
What we do know is that the outage began in Spain and propagated outward. Portugal, more exposed and with lower relative grid investment, was unable to absorb the shock. France, by contrast, withstood the disruption. There has been some disagreement but as I write the latest is Spanish Prime Minister Pedro Sánchez cited a “strong oscillation” in the European grid, and Portuguese grid operator REN pointed to induced atmospheric variation caused by high temperatures. It is an unfolding story and rather than speculate, it’s useful to note comparative infrastructure investments.
To put grid investment into context, both Spain and Portugal have invested around €36 per person per year over the last decade. France spent around €82 per person per year over the same period. In the five years leading up to the blackout, Spain has the lowest ratio of grid spending to clean-power investment in Europe. In looking for silver linings in the extremely dark cloud that is the blackout, this can no longer be ignored. Investment will follow, grid resilience isn’t a luxury. In a world of increasingly extreme weather and relentlessly increasing demand for power, it is a necessity.
The misinformation machine
The blackout was another example of how quickly misinformation can proliferate in a vacuum. Within hours of the event, Fox News’s Sean Hannity linked the outage to the fact that Spain had recently run on 100% renewables for a short period and had over 50% renewables penetration, with the sentence “that is what you get”. For all the analysis that was provided he may as well have said “they play a lot of soccer over there, that is what you get” but the message was loud and clear, despite all authorities saying they don’t know conclusions that suited a particular narrative were instantly seized.
This flags up a deeper asymmetry in the public communications battlefield. The fossil fuel industry has spent decades building a highly coordinated, well-funded misinformation machine. As far back as the 1950s, oil companies knew the risks fossil fuels posed to the climate. Instead of acting, they funded front groups, crafted disinformation campaigns, and cast doubt on science to delay regulation. Reports like the U.S. Senate’s “Denial, Disinformation, and Doublespeak” outline how major oil companies have continuously shifted tactics to maintain influence, rebranding themselves as part of the climate solution while undermining meaningful progress behind the scenes.
By contrast, proponents of net-zero are often slow, cautious, and underfunded. Their messaging tends to be data-driven and sober which, while scientifically robust, rarely breaks through the noise of sensationalist headlines or emotionally charged falsehoods. This imbalance is costing us. When a blackout is instantly blamed on clean energy despite zero supporting evidence we see just how powerful and persistent the fossil fuel narrative machine remains.
Resilience isn’t a luxury. It's the price of transition.
Globally, electricity use increases by approximately 2.6% every year. That means every two decades, we must build an entirely new energy system the size of our current one, just to keep up. Complicating matters further, today’s grids were not designed for a world of distributed, intermittent power sources. While there are compelling reasons to scale up wind and solar, once renewables exceed 50% of grid penetration, the system’s nature fundamentally changes. It is no longer a matter of managing consistent base load supply with peaker plants but of orchestrating a highly variable, real-time network.
A modern grid isn’t just about cables and substations, it’s about agility, redundancy, and the ability to stay balanced when conditions change fast. And as renewables grow, these conditions will change faster and more often. The real question isn’t whether we can build clean energy systems, but whether we can build ones that evolve to meet the needs of the moment.
The blackout that swept across Spain and Portugal is a reminder that our energy system must be built on resilient foundations. European countries' grid investments typically range between 0.2% and 0.3% of GDP. This is a similar level to the US which has seen five major blackouts over the last two years. By contrast China’s investment levels are estimated at 0.45% to 0.55% of GDP.
Without sustained investment and modernisation and with increasingly unpredictable extreme weather events, power cuts will become more frequent, not anomalies. The electricity transmission system is not sexy and investing in it will not get votes, but allowing it to fail will cost more than elections.
So what can we do?
First, we must resist the temptation to politicise power outages. Knee-jerk blame games undermine public understanding and erode trust. Instead, we need to listen to qualified people who investigate and present the facts carefully.
Second, we need to invest in better climate communication. Net-zero advocates must build stronger coalitions, craft clearer narratives, and engage more broadly and boldly with the public. Silence and nuance cannot compete with volume and fear.
Third, our grids themselves must be modernised to handle an increasingly complex mix of inputs and weather extremes. The Iberian blackout wasn’t a failure of renewables, nor a conspiracy. It was a reminder that systems can be vulnerable and need constant reinforcement and upgrade to cope with a changing world.
Understanding those vulnerabilities and protecting against their exploitation by bad actors or misinformation is the real work ahead.
illuminem Voices is a democratic space presenting the thoughts and opinions of leading Sustainability & Energy writers, their opinions do not necessarily represent those of illuminem.
