Major power cut in Spain and Portugal may have been caused by 'rare atmospheric phenomenon'

A major power cut hit Spain and Portugal on Monday, including their capitals, knocking out subway networks, phone lines, traffic lights and ATM machines.

Spanish generator Red Electrica said the incident has affected the Iberian peninsula and is being assessed, adding that restoring power to large parts of the country could take six to 10 hours.

The Portuguese Cabinet convened an emergency meeting at the prime minister’s residence, and Spanish Prime Minister Pedro Sanchez visited Red Electrica to follow efforts to restore power to the grid.

The operator of the Portuguese power grid, REN, has said that power supply interruptions in Portugal were due to a fault in the Spanish electricity grid related to a rare atmospheric phenomenon.

It said extreme temperature variations in the interior of Spain caused anomalous oscillations in the very high voltage lines. It said this phenomenon is known as "induced atmospheric vibration".

The oscillations caused synchronisation failures between the electrical systems, REN said, leading to successive disturbances across the European network.

The countries have a combined population of more 50 million people, but it was not immediately clear how many were affected.

Spain’s public broadcaster, RTVE, said a major power outage hit several regions of the country just after midday local time, leaving its newsroom, Spain’s parliament in Madrid and subway stations across the country in the dark.

A graph on Spain’s electricity network website showing demand across the country indicated a steep drop at around 12.15pm from 27,500MW to near 15,000MW.

In Portugal, a country of some 10.6 million people, the outage hit the capital, Lisbon, and surrounding areas, as well as northern and southern parts of the country.

Portugal’s government initially said the incident appeared to stem from problems outside the country, an official told national news agency Lusa.

“It looks like it was a problem with the distribution network, apparently in Spain. It’s still being ascertained,” Cabinet Minister Leitao Amaro was quoted as saying.

Video shown on Spanish television showed people evacuating metro stations in Madrid, and empty stations with trains stopped in Barcelona.

Spain’s traffic department asked citizens to avoid using their cars as much as possible due to the power outage, which affected traffic lights and electric road signs.

In Terrassa, an industrial town 31 miles (50km) from Barcelona, stores selling generators were out of stock after people queued up to buy them.

Portuguese police placed more officers on duty to direct traffic and cope with increased requests for help, including from people trapped in lifts.

Portuguese hospitals and other emergency services switched to generators.

Motorists in Lisbon, Portugal, drive past traffic lights that stopped working during the power outage (Armando Franca/AP)

Portugal’s National Authority for Emergencies and Civil Protection said back-up power systems were operating.

Several Lisbon subway cars were evacuated, reports said.

Also in Portugal, courts stopped work and ATMs and electronic payment systems were affected. Traffic lights in Lisbon stopped working.

It was not possible to make calls on mobile phone networks, though some apps were working.