Light. Light has been part of the human story since the very beginning. We built fires to stave off the darkness and discovered electricity to generate enough light to brighten our cities across the globe.
So what happens when the lights go out?
On 28 April 2025 the Iberian Peninsula (Spain and Portugal) experienced the largest European blackout in 20 years.1 The complete loss of power to the region lasted over half a day and by the next morning power had been restored to almost the entire region. Blackouts pose a dangerous risk as the loss of power means that critical machinery in places such as hospitals cannot function properly, at night we are deprived of streetlights vital to safe nighttime travel, and in our modern, digital age we lose access to many electronic systems that govern our lives.
The oil and gas industry did not escape unscathed; major refineries and petrochemical producers were forced to shut down entirely. All five of Repsol’s refineries were shut down, Moeve halted operations at its chemical and refining plants, and Dow closed its plants at its Tarragona industrial complex.2 It took nearly a week to bring all of the plants back online, which severely impacted revenues and production output for the industry.
In the wake of the blackout people are seeking to understand just why these incidents happen. There are, of course, several reasons as to why blackouts occur. First is what are known as ‘Acts of God’, essentially the influence of extreme weather and natural phenomena. While natural disasters can pose a level of risk, lightning strikes and solar flares have also been known to affect grid stability. Some consideration should also be given to the possibility of human interference. Whether it stems from intentional cyberattacks that have become an ever-increasing worry in the current geopolitical climate, or from simple human error, the hand of man can be at fault. There is also a simpler answer available. Grid glitches, which occur through simple mechanical failures, can cascade into more serious issues; glitches are more likely in a renewable rich grid like the one we see in Spain – owed to the fact that the system was initially built with fossil fuels in mind, not renewable energy sources.
And finally there are ‘Black Swan’ events. Incidents which occur in a cascade of small errors that simply cannot be predicted or planned for as they are, by their very nature, unpredictable. Such was the case in Spain in April. Investigations into the incident revealed that the problem came about when there was a sudden loss of power to three substations across three Spanish provinces in Granada, Badajoz, and Seville, all within seconds of each other, which led to a 2.2 GW dip in energy generation. This, in turn, triggered a series of grid disconnections.3
What this highlights is just how vulnerable these grids can be and the fact that power integration needs to be secured further. Otherwise, what is to stop a blackout of a grander, potentially continental scale, next time?
- AMBROSE, J., ‘Blackouts can happen anywhere: how power systems worldwide can collapse’, The Guardian, (2 May 2025)
- MAHER-BONNETT, G., REIMI, I., SANDS, A., and EGOY, M., ‘Power outage hits Spanish refineries: Update’, Argus Media, (28 April 2025)
- LOMBARDI, P., ‘Granada substation power loss pinpointed as ground zero of Spain’s blackout’, Reuters, (14 May 2025)
