There have been suggestions that Spanish authorities were testing the limits of their dependence on renewable energy before a significant power outage hit the Iberian Peninsula last month.

Following the disruption that affected the lives of millions in Spain and Portugal, people are seeking more information on the root cause of the power cut. Questions have been raised about Spain’s heavy reliance on renewable energy sources, especially as the country plans to phase out nuclear reactors.

In response to the criticisms, Spain’s socialist Prime Minister, Pedro Sanchez, has defended the government’s position and urged the public to wait for the results of the investigation into the historic blackout.

Spain’s electric grid operator Red Eléctrica de España pinned it on a significant and unprecedented drop in power generation. 

Now, it has been suggested that the Spanish government was carrying out an experiment before the country’s grid system crashed, The Telegraph reports. 

Under said test, authorities had been trialling how far they could push their reliance on renewables as they prepared for Spain’s phase-out of nuclear reactors from 2027. 

The Spanish Association of Electrical Energy Companies (Aelec), which has criticised the inquiry into the blackout’s cause, has now said it was not the country’s generators that failed to deliver power to the grid, but rather it was the grid that failed to manage it and then shut down automatically. 

The head of Spain’s photovoltaic association, Jose Donoso, had made a similar suggestion earlier this month, telling newsoutlet 20Minutos: ‘It’s a matter of logic; the fact that the entire system goes down because of a photovoltaic plant makes no sense.

‘We suffered the consequences of a grid disruption, but we didn’t cause it.’ 

Aelec said the authorities had essentially confined the trial to a 20-second span on April 28, and ignored a series of oscillations in tension that began days earlier and transcended ’emergency’ levels across the peninsula for two hours leading up to the blackout.

The association added that the authorities did not substantiate their claim that it all began with a sudden drop of 2.2 gigawatts in power supplied to the grid.

It comes after the sweeping power outage last month raised questions about the electricity grid in a region not normally known for blackouts. 

Spain’s top criminal court, the Audiencia Nacional, said it was investigating whether the blackout was ‘an act of computer sabotage on critical infrastructure’ that could be classified as ‘a terrorism offence’.

The government set up a commission to investigate what triggered the incident, and refused to rule out any hypothesis.

Spain’s grid operator ruled out a cyber attack.

Local media soon began pointing to historic reports warning that the rapid integration of renewable energy sources could cause fluctuations in power levels, potentially leading to widespread blackouts.

The outage, said to be one of the worst ever in Europe, started on the afternoon of April 28 and lasted through nightfall, affecting tens of millions of people across the Iberian Peninsula. 

Offices closed and traffic was snarled in Madrid and Lisbon, while some civilians in Barcelona directed traffic. Train services in both countries stopped. 

It disrupted businesses, hospitals, transit systems, cellular networks and other critical infrastructure.

Emergency services and rail workers in Spain had to help evacuate some 35,000 people from over 100 trains that stopped on the tracks when the electricity was cut. 

Just a month after the widespread powercut, all major mobile networks went down in Spain this week. 

Movistar, Orange, Vodafone, Digimobil and O2 were all reported to have been affected by outages hitting professional services, including health centres.

Complaints soared as landline, internet and emergency contact services were knocked offline early Tuesday morning. 

Madrid, Andalucía, Galicia, the Basque Country, Aragon, Navarra, Extremadura and the Valencian Community were all reportedly affected.

Networks contracted with Telefónica appeared to have been hit, but outages did not appear to be affecting individuals’ network access.

Spain generated nearly 57% of its electricity in 2024 from renewable energy sources like wind, hydropower and solar, according to Red Eléctrica.

About 20% came from nuclear power plants.

In 2019, Sánchez’s government approved a plan to decommission the country’s remaining nuclear reactors between 2027 and 2035 as it expands its share of renewable energy even further. 

The country aims to generate 81% of its electricity by 2030 from renewable sources.

It is rare to have such a widespread outage across the Iberian Peninsula, with a combined population of about 60 million people. 

Spain’s Canary Islands, Balearic Islands and the territories of Ceuta and Melilla, located across the Mediterranean in Africa, were not affected.