A massive blackout left tens of millions of people without electricity in Argentina, Uruguay and Paraguay on Sunday in what the Argentine president called an “unprecedented” failure in the countries power grid.
Authorities were working frantically to restore power, but 10 hours after the country went dark, a third of Argentinas 44 million people were still without power and the cause of the outage remained unclear.
As the sun rose over the darkened country, Argentine voters were forced to cast ballots by the light of cell phones in gubernatorial elections. Public transportation was halted, shops closed and patients dependent on home medical equipment were urged to go to hospitals with generators.
“This is an unprecedented case that will be investigated thoroughly,” Argentine President Mauricio Macri said on Twitter.
Argentinas power grid is generally known for being in a state of disrepair, with substations and cables that were insufficiently upgraded as power rates remained largely frozen for years.
The countrys energy secretary said the blackout occurred at 7:07 am local time when a key Argentine interconnection system collapsed.
The Argentine energy company Edesur said on Twitter that the failure originated at an electricity transmission point between the power stations at the countrys Yacyretá dam and Salto Grande in the countrys northeast.
But why it occurred was still unknown.
An Argentine independent energy expert said that systemic operational and design errors played a role in the power grids collapse.
“A localized failure like the one that occurred should be isolated by the same system,” said Raúl Bertero, president of the Center for the Study of Energy Regulatory Activity in Argentina. “The problem is known and technology and studies (exist) to avoid it.”
By mid-afternoon, power had been restored to most of Uruguays 3 million people. But in Argentina, only 65% of the nations grid was back up and running as of 5 pm local time, the national news agency Telam reported.
Energy Secretary Gustavo Lopetegui said workers were working to restore electricity nationwide by the end of the day.
“This is an extraordinary event that should have never happened,” he told a news conference. “Its very serious.”
Uruguays energy company UTE said the failure in the Argentine system cut power to all of Uruguay for hours and blamed the collapse on a “flaw in the Argentine network.”
In Paraguay, power in rural communities in the south, near the border with Argentina and Uruguay, was also cut.
The countrys National Energy Administration said service was restored by afternoon by redirecting energy from the Itaipu hydroelectric plant the country shares with neighboring Brazil.
In Argentina, only the southernmost province of Tierra del Fuego was unaffected by the outage because it is not connected to the main power grid.