There’s nothing like a major blackout to get people worked up about the energy system. And the blackout that hit the Iberian Peninsula at 12.30 on April 28 this year was certainly major. Power went out across all of mainland Spain and Portugal, stranding train travellers and severing telecommunications links.
By and large, Spain’s citizens behaved in an exemplary manner, remaining calm as events unfolded. Spain’s grid operator, Red Eléctrica, also responded in a commendable way, bringing power back on in a controlled fashion so full supplies were restored within 16 hours of the incident.
But finger-pointing had begun well before the lights came back on, with many questioning whether an over-reliance on intermittent renewables was the cause.
Spain’s main opposition party, which did an admirable job of delaying the country’s energy transition while previously in power, tried to pin the blame on the closure of nuclear reactors, despite the fact that they were supplying more than 10% of generation—a typical level of baseload—when the blackout happened.
The Spanish government, meanwhile, has refused to be drawn into a discussion of the causes beyond noting that 3 GW of pumped hydro capacity was available when the incident happened, which should have been enough to react to any imbalance.
The reasons for the loss of supply are “enormously complex,” said Sara Aagesen Muñoz, Spain’s Third Deputy Prime Minister and Minister for the Ecological Transition. “There are many hypotheses about what happened.”
The finger-pointing has begun...
It is unlikely the cause will be established for some time. An investigation by the European Network of Transmission System Operators for Electricity is expected to last around six months.
A Spanish government commission looking into the incident could arrive at conclusions somewhat sooner, given calls for a rapid explanation of events—but not by much if the experience in other markets is anything to go by.
An investigation into an August 2019 power outage that affected more than a million UK customers did not close until June 2020, for instance. And a report on a September 2016 blackout affecting the whole of South Australia was not released until December 2018.
A long wait will do little to prevent speculation over the causes of the Iberian power loss, and doubts over the role of renewables seem inevitable given that more than half of Spain’s power supply was coming from photovoltaic solar at the time of the blackout. Yet while this seems a lot, it is not an unusual level for the Spanish grid.
Indeed, since 2023 there have been several periods when all of Spain’s mainland electricity demand has been covered by renewables. And those in the know have cautioned against rushing to blame clean energy sources for the blackout.
“Some people are using this event to attack renewables, but this has nothing to do with renewables,” says Daniela López, an energy forecasting project advisor with Barcelona-based AleaSoft Energy Forecasting. “In fact, it is something that has happened in other countries at times of lower renewables development.”
In 2003, for example, a tree falling on a high-voltage line in Switzerland blacked out the whole of the Italian Peninsula. And blackouts—often scheduled, but sometimes not—are a common feature of electricity supply in South Africa, where 86% of generation comes from coal plants.
Nevertheless, and regardless of the outcome of the investigations underway, it is legitimate to ask what Spain, Portugal and other countries can do to lessen the chances of failures on grids dominated by renewables. One popular suggestion is to increase the amount of battery storage on the grid.
Red Eléctrica has largely been able to accommodate world-leading levels of intermittent renewable energy generation on the electricity network thanks to a massive 6 GW of pumped hydro storage capacity, while Portugal has almost 3.7 GW more.
Together, the two countries have the fourth-largest amount of pumped hydro capacity in the world, beaten only by China, Japan and the US. This has allowed Spain and Portugal to integrate renewables with relatively modest amounts of battery storage capacity.
Spain has just 60 MW, said Kristian Ruby, secretary general of the electricity industry body Eurelectric, in a podcast for Montel News. Pratheeksha Ramdas, senior new energies analyst at Rystad Energy, said in the same podcast that Spain’s grid would benefit from more batteries.
Pumped hydro notwithstanding, “they don’t have enough storage,” she said. “One advantage of having grid-forming batteries is that they are advanced battery storage systems that can independently stabilise and support the electricity system.”
The Spanish authorities are aware of a need for greater grid resilience, with plans for a capacity market and an announcement by Aagesen in March of a €700 million procurement of flexible resource. “We hope this capacity mechanism and this first auction will be a catalyst and this will be the year of storage,” she said in May.
Spain’s grid would benefit from more batteries
More battery storage would not only help the Iberian Peninsula overcome unexpected grid perturbations but also improve the business case for more solar power, which is suffering in Spain because of price cannibalisation.
And for those wondering whether Spain should be putting the brakes on renewables rather than building more of it, price is an important consideration.
One detail that has been drowned out by the noise around the Iberian blackout is the fact that when it happened Spain’s wholesale electricity price had fallen into negative territory and the country was exporting supplies to Portugal, France and Morocco, as well as storing pumped hydro energy.
Again, this situation—low or negative electricity prices and the ability to export to neighbouring countries—is not unusual for Spain and is entirely thanks to the preponderance of renewables in the country. It is only the impact of charges and taxes that prevent Spain from having one of the most competitive electricity rates in Europe.
In this respect, the Iberian Peninsula is in a similar position to other European energy islands, including Italy and the British Isles. Electricity in these places is costly, and blackouts remain a risk—but these challenges could be solved, not worsened, by the transition to a fully renewable energy system backed by abundant battery storage.
Publish date: 21 May, 2025