Power has finally been restored to over 1 million Puerto Rican residents after a fire at a main power plant resulted in the largest blackout so far this year across the U.S territory.

According to LUMA Energy, crews were able to restore power to its 1.5 million customers by early morning on Sunday, April 10.

LUMA is a joint enterprise between Quanta Services and the Canadian energy company ATCO. LUMA took over operation of the power grid from its previous utility, Puerto Rico Electric Power Authority last year. It has been in charge since last June.

“While power restoration has occurred for 99.7 percent of customers, LUMA and PREPA continue to work to stabilize the grid and reduce the future risk of intermittent power outages,” LUMA said in a statement on its website. 

The major power outage began as an island-wide blackout that forced schools and courts to close for days and caused other interruptions for Puerto Rico’s 3.2 million residents. 

According to LUMA’s vice president, Kevin Acevedo, the outage started near 9:00 pm on Wednesday, April 6, after an unspecified failure led to a fire at the Costa Sur Substation. Firefighters have since put out the flames at the facility, which is located outside Guayanilla on the southwest coast. 

The exact cause of the blaze was not immediately known. 

Josué Colón, executive director of the Puerto Rico Electric Power Authority, said that all customers lost power because “all the generating units went offline.” 

Colón told El Nuevo Día that multiple federal agencies visited the plant to conduct a forensic evaluation of the area, and are still gathering information. 

"Our engineers have been with them hand in hand, providing all the related technical information and videos, because we also have videos and closed-circuit cameras in all those critical facilities," Colón said.

In addition to power disruptions, the outage also resulted in water service interruption for tens of thousands of homes and businesses. 

The massive blackout incited widespread groans and complaints across the island, with many who rely on insulin or respiratory therapies concerned about how long they would be without power. 

By the afternoon of Thursday, April 7, all hospitals were operating solely through power restoration or generators. 

“We have begun the detailed investigation into this event and will be fully transparent with our customers, regulators, and the legislature with our findings to determine what actions must be taken to reduce the threat of such large outages,” wrote Wayne Stensby, LUMA’s president and CEO. 

When LUMA took over transmission and distribution in June 2021, Gov. Pedro Pierlusi said the company promised to reduce power interruptions by 30% and the length of outages by 40%. 

However, in the same month, a large fire at a substation in San Juan left hundreds of thousands of island residents without power. 

To make matters worse, the U.S territory is still recovering from the damage brought on by Hurricane Maria, as well as an island-wide blackout from a power plant fire in 2016. 

Emergency repairs have been made, but reconstruction efforts have not yet begun. 

“This type of breakdown in our system is unacceptable. I will not rest until we achieve the goal of modernizing and replacing our old and outdated electrical system,” Gov. Pierluisi tweeted on April 8.