SAN JUAN, Puerto Rico (AP) — Puerto Rico's governor on Monday urged people to moderate their energy consumption as she warned that the island has no additional generation to fall back on days after a massive blackout hit the U.S. territory.

Gov. Jenniffer González said officials are waiting for an explanation from Luma Energy, a private company that oversees transmission and distribution of power in Puerto Rico, about what caused the island-wide outage on April 16. It affected 1.4 million customers and left more than 400,000 others without water.

The governor announced that two subcommittees have been created: one to help the island’s so-called energy czar to audit Luma’s contract and another to identify potential companies to replace Luma if its contract is terminated.

“There have been multiple incidents,” she said when asked whether the blackout was reason enough to cancel Luma’s contract, something she pledged to do while campaigning for governor. “The operator sold itself as an expert...That perception of expertise has proven to be false.”

Luma did not immediately respond to a request for comment.

The company has five days to explain why a transmission line failed and provide details about whether it complied with required flyovers of transmission lines to ensure they remain free of tree branches and other obstructions.

A preliminary report from Luma released late Friday found that a transmission line apparently failed because of overgrown vegetation.

“The fact that this happened indicates either that the patrol didn’t take place or that the line inspector didn’t detect it. That tree didn’t grow there overnight,” said Josué Colón, Puerto Rico’s so-called energy czar and former executive director of the island’s Electric Power Authority.

He said protective equipment that was supposed to detect and isolate the failure also failed, which caused the transmission system to collapse.

“The system then enters a cascade event that is irreversible,” he said. “The important thing now is that this doesn’t happen again.”

González said Puerto Rico’s government has launched its own investigation into the blackout to compare it to Luma’s report and determine any discrepancies.

González stressed that the administration of U.S. President Donald Trump has been in communication with her since the outage occurred, adding that the U.S. Environmental Protection Agency authorized the extended use of industrial generators.

On Monday, some 20,000 customers remained without power, although officials said other issues were to blame.

“Our system is fragile,” González said.

Earlier on Monday, she, Colón and other officials met behind closed doors to review Luma's preliminary findings, recommend next steps and talk about an ongoing search for a company that can provide 800 megawatts of additional generation in the upcoming months.

April 16 marked the second massive blackout to hit Puerto Rico in less than four months. The previous one happened on New Year's Eve.

Puerto Rico has struggled with chronic outages since September 2017, when Hurricane Maria hit the island as a powerful Category 4 storm, razing a power grid that crews are still struggling to rebuild.

The grid already had been deteriorating following decades of a lack of maintenance and investment under the state's Electric Power Authority, which is struggling to restructure more than $9 billion in debt.

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