By Leonardo Goy
BRASILIA, Feb 4 (Reuters) - Some of Brazil's most populous regions suffered sporadic power outages on Tuesday, raising election-year fears of shortages in a country with a long history of blackouts.
The shortages, which occurred during record heat and low reservoir levels at the country's hydroelectric plants, were caused by short circuits in transmission lines in the north-central state of Tocantins, said Brazil's national grid operator, ONS.
The outages extended to as many as 6 million consumers and industrial users in Brazil's biggest cities, usage-heavy regions further south and across parts of the country's farm belt in the central west.
The government on Tuesday moved quickly to dismiss concerns that the shortages were symptoms of a bigger problem. President Dilma Rousseff, already wrestling with a sluggish economy and consumer unease because of rising prices, faces a re-election bid this year.
Just one day before the outages happened, Energy Minister Edison Lobão told reporters that "we see no risk of energy shortages."
Record heat in January and a prolonged lack of rain have left hydroelectric reservoirs at low levels, which forced power companies to supplement Brazil's hydroelectric supply by buying energy from thermal-fired plants. If consumers face more outages or higher bills because of the changing power mix, energy woes could influence voting in a country where blackouts led to power rationing as recently as 2002.
The outages, according to the grid operator, happened when the short circuits triggered a deliberate shutoff in transmission to some distributors. The shutoff, officials said, kept shortages from being even more widespread.
The system "worked just as it's supposed to work," said Maurício Tolmasquim, the president of the Energy Research Company, a government agency, at a press conference.
Companies reporting outages included those serving Brazil's two largest metropolitan areas: AES Eletropaulo SA, the distributor for Sao Paulo, and Light SA, the main distributor in Rio de Janeiro. Nine other utilities also experienced shortages, the government said.
Officials said they need to investigate what caused the short circuits but added that they were not the result of any sort of overcapacity or because of surging demand on the grid.
Brazil's existing power capacity can supply about 50 percent more than has ever been required during peak periods of usage, they said.
Yet the failures happened at a time when Brazilians want more power for air conditioners, fans and refrigerators. January was the hottest month on record in parts of Brazil including its biggest city, São Paulo.
Reservoirs in the country's south and central west regions are at about 40 percent of their capacity, according to government figures. The average capacity last February, which also was drier than usual, was about 45 percent, while capacity at the reservoirs two years ago was at 80 percent.
Tolmasquim said on Tuesday that the government would evaluate the costs for supplementing the utilities' hydroelectricity with thermal-generated energy and could consider financial relief for those companies.
Meanwhile, government officials, like many across Brazil, are waiting for rain.
"You're never without rain forever," said Hermes Chipp, director of ONS, the grid operator. "The wet season may get delayed, but eventually it arrives."