Power supply restored in most European countries after mysterious blackout

The lights came back on across much of Spain and Portugal on Tuesday evening after a massive power outage hit the Iberian Peninsula, leaving commuters stranded on trains and lifts and millions without phone service or internet access.

By Tuesday morning, power had been restored to almost 90% of mainland Spain, according to grid operator REE. Around 6.2 million of Portugal's 6.5 million households had their power restored overnight, according to Portugal's national grid operator. The lights were also back on in Madrid and the Portuguese capital, Lisbon, The Guardian reports.

Only one corner of the peninsula, which has a population of almost 60 million, has managed to avoid a power outage, but there is no clear reason for the outage, The Guardian notes.

Portuguese Prime Minister Luis Montenegro said the cause of the outage was “likely in Spain.” Spanish Prime Minister Pedro Sanchez said all possible causes were being analyzed and warned the public not to speculate because of the risk of “misinformation.”

Earlier, Portugal's electricity grid operator REN blamed the power outages on extreme temperature swings, leaving both Iberian countries without trains, metros, traffic lights, ATMs, telephone service and internet access.

People were trapped in elevators, stuck in trains and traffic jams, and abandoned at airports. Hundreds of people trudged through pitch-black subway tunnels using flashlights from their phones to light their way; others tried to buy essentials in cash-only supermarkets or took longer walks home from work.

At 12:33 p.m. local time, mobile phone service and internet access went out. Hospitals postponed routine surgeries but used generators to handle critical cases, and while online banking services were able to function on backup systems, most ATM screens were blank.

In scenes reminiscent of the 2003 blackout that caused widespread power outages in the north-east US, rail services were halted in the Iberian Peninsula, air travel was disrupted and traffic lights were knocked out. Hundreds of people had to be rescued from stuck elevators, The Guardian reports.

Madrid Mayor José Luis Martínez-Almeida urged people to reduce their travel and stay where they are, adding: “It is important that emergency services can respond quickly.” Play at the Madrid Open tennis tournament has been suspended.

By 10pm local time on Monday, 62% of Spain's substations were back online (421 out of 680) and 43.3% of power needs had been met, while Portugal's grid operator REN said it had restored power to 85 of the country's 89 substations.

Red Eléctrica previously warned that it could take six to 10 hours for power supplies to be fully restored after what the company called an “exceptional and quite extraordinary” incident.

The restoration of electricity supply on one of Madrid's main thoroughfares in the Argüelles district has caused cheers and thunderous applause from many passers-by.

Spanish Prime Minister Sanchez said the power outage occurred at 12:33 p.m., when 15 gigawatts of power generation, equivalent to 60% of all energy used, suddenly disappeared within five seconds.

“This has never happened before,” added the head of the Spanish government. “Experts have not yet been able to determine what caused this sudden interruption of supplies. But they will. All potential causes are being analyzed, and no hypothesis or possibility is being ruled out.”

Sanchez thanked France and Morocco for supplying extra electricity to Spain and said the current shortage would be met with gas and hydroelectric power.

Portuguese operator REN said the outage was caused by a "rare atmospheric event" in which extreme temperature swings in Spain caused "abnormal fluctuations" in very high voltage lines.

The company says the phenomenon, known as “induced atmospheric vibration,” caused “synchronization failures between electrical systems, leading to successive outages across the interconnected European grid.”

Widespread power outages are unusual in Europe, The Guardian reports. In 2003, a fault in a hydroelectric line between Italy and Switzerland led to power outages lasting about 12 hours, while in 2006, an overloaded power grid in Germany led to power outages in parts of the country, as well as in France, Italy, Spain, Austria, Belgium and the Netherlands.

Spain's prime minister said additional National Police and Civil Guard officers had been deployed across the country to keep people safe overnight, adding that hospitals were functioning well thanks to the efforts of health workers. He said telecommunications services were still being disrupted, mainly due to a lack of power to antennas.

Prime Minister Sanchez said only 344 of the 6,000 flights operating in Spain on Monday were cancelled and that the country's road network was working well, except for some delays.

The main disruption was on the rail network, where 35,000 passengers stranded on more than 100 trains were being assisted by rail companies and the military's emergency response unit. Eleven more trains, which had been stranded in remote areas, were still waiting to arrive.

Traffic lights stopped working in Madrid and other cities, causing gridlock as vehicles slowed to avoid collisions, and the metro was stopped. Spain's National Roads Agency urged motorists to avoid the roads if possible.

El País newspaper posted photos and videos on its website showing commuters moving through darkened metro tunnels in the Spanish capital, with police directing traffic on the city's streets. The footage also showed reporters working by torchlight.

Spain's health ministry said on social media that it was in contact with regional authorities to assess the extent of the widespread power outage, but assured the public that extra systems had been installed in hospitals.

In Portugal, power outages affected the capital Lisbon and its surrounding areas, as well as the northern and southern regions of the country. Lisbon metro cars were evacuated and ATMs and electronic payment systems were switched off.

Spanish Prime Minister Sanchez said eight of the country's 17 autonomous regions - Andalusia, Castilla-La Mancha, Extremadura, Galicia, La Rioja, Madrid, Murcia and Valencia - had declared a level three emergency, putting the central government in charge of the response. He said schools in those areas would reopen on Tuesday but would not hold regular classes.

He said the situation across the country remained very “asymmetrical” on Monday evening, with some regions already having 90% of power restored, while others had less than 15%.