Argentina’s government struggled to explain on Monday the cause of a huge blackout that left almost 50m people across the country and in neighbouring Uruguay without power for up to 15 hours.
Gustavo Lopetegui, energy secretary, told local radio that Sunday’s shutdown was caused when a power surge in a major transmission line in the north of the country spread to the entire national grid, though he said it could take up to two weeks to identify exactly why the blackout had been so severe.
“The problem and the question is: why did a system that is capable of isolating that section not do so?” Mr Lopetegui was referring to a transmission line running south from the Yacyretá hydroelectric dam on Argentina’s border with Paraguay to another hydroelectric dam at Salto Grande on its border with Uruguay.
Although Edesur, an electricity distribution company, announced that the crisis had been “100 per cent fixed” on Sunday night, more than 10,000 people in Buenos Aires remained without electricity on Monday morning.
Sunday morning’s blackout halted underground trains, knocked out traffic lights and left homes in darkness on what was a winter morning in the southern hemisphere, but no major accidents or casualties were reported. Activity on the streets of Buenos Aires remained subdued on Monday as many people stayed at home on what was a national holiday.
The government attempted to reassure citizens that a significant failure like Sunday’s had “zero” chance of happening again, despite the suboptimal state of Argentina’s electricity grid.
Mr Lopetegui did “not dare to offer a hypothesis” for the cause of the incident, saying he did not have all the necessary information, although he rejected the possibility of a cyber attack.
Electricity experts said a blackout on the scale of Sunday’s disaster was not unprecedented. The northeastern US and Canada, for example, suffered a major outage in 2003 affecting tens of millions of people.
Alison Silverstein, who led an investigation into that blackout, said electricity grids were designed with automatic relays and schemes that measure conditions and quickly shut off a piece of the grid or reroute the electricity to ensure safety if power levels go outside programmed settings.
Ms Silverstein, who now works as an independent consultant based in Austin, Texas, said the most common reasons for problems in grid operations were inaccurate or outdated grid models, inadequate recognition of real-time grid conditions and unintended errors in setting up the automated equipment operations, though she stressed that she had not studied the Argentine case in detail.
The Argentine power system collapsed at 7.07am on Sunday, when national consumption was relatively low.
Mr Lopetegui said that the “extraordinary” episode should not have happened.
“There was a fraction of a second between the moment in which the simple failure happened and the system disconnecting the whole country without human intervention, instead of isolating that failure,” he added. “It has never happened before in the history of Argentina.”
Blackouts have been a sensitive political issue since utility charges were frozen after the country’s 2001-02 economic crisis, after which Argentina’s electricity infrastructure suffered from under-investment by a lossmaking private sector. The price freeze caused an increase in consumption, straining the system further.
Sunday’s power cut was therefore a serious embarrassment for President Mauricio Macri, who is facing a difficult election campaign amid a recession. Since he took power in 2015, electricity charges have been increased several times over, a hugely unpopular move that was justified as necessary to boost investment and prevent blackouts.
Alberto Fernández, Mr Macri’s main rival in October’s presidential elections, demanded that the government solve the power crisis, saying that Mr Macri’s reforms had apparently only benefited his friends in the business sector while millions of Argentines had to shell out “a fortune” thanks to the price rises.
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