Tesla CEO Elon Musk touts batteries during Puerto Rico blackout

FILE-- Tesla said over 1,000 Tesla batteries were on the ground in Puerto Rico delivering power at 662 locations. In the hours after Puerto Rico went dark, Elon Musk, co-founder and CEO of Tesla, tweeted Wednesday, “Tesla batteries are currently live & delivering power at 662 locations in Puerto Rico. Team is working 24/7 to activate several hundred more.” less FILE-- Tesla said over 1,000 Tesla batteries were on the ground in Puerto Rico delivering power at 662 locations. In the hours after Puerto Rico went dark, Elon Musk, co-founder and CEO of Tesla, tweeted ... more Photo: Tesla Photo: Tesla Image 1 of / 5 Caption Close Tesla CEO Elon Musk touts batteries during Puerto Rico blackout 1 / 5 Back to Gallery

Almost seven months to the day Hurricane Maria sent Puerto Rico into a state of emergency as scores of people were found dead across the island and food and water were in desperately short supply, a power outage on Wednesday — estimated to be one of the largest in U.S. history — left few energy options to more than 3 million residents beyond batteries supplied by a Bay Area tech company.

In the hours after Puerto Rico went dark, Elon Musk, co-founder and CEO of Tesla, tweeted Wednesday, “Tesla batteries are currently live & delivering power at 662 locations in Puerto Rico. Team is working 24/7 to activate several hundred more.”

Since the destruction Hurricane Maria wrought on Sept. 20 — the U.S. government estimated the death toll at 64, while New York Times placed the number above 1,000 — Bay Area organizations, tech investors and even restaurants have taken part in relief efforts. For its part, Tesla has sent more than 1,000 batteries to communities in the the U.S. territory, according to a company statement.

The island went dark Wednesday morning, the first sweeping blackout to hit the region since the hurricane, which destroyed about 75 percent of power distribution lines.

As of Thursday morning, the Puerto Rico Electric Power Authority said it had restored electricity to more than 80 percent of customers. The electrical outage was reportedly caused by an excavator hitting a transmission line.

Remaining customers were expected to receive power later on Thursday, the company said.

President Donald Trump received heavy criticism last fall for the federal response to the island’s crisis, and as of noon Thursday he had not made a statement regarding the latest outage.

Since Hurricane Maria, homes across the island have paired solar panels with Tesla’s Powerwall batteries to provide clean energy and back-up electricity for individual families that may face a disaster like the one that reignited Wednesday, the company said.

In an effort to restore electricity to rural communities, the company said, it built a microgrid to provide electricity to 12 homes in Barrio Montones in Las Piedras.

The microgrid reportedly relies on underground distribution lines and smart meters to support a 58 kilowatt solar system and 135 kilowatt-hours of Powerwall batteries, resulting in sustainable electricity for at-risk residents.

Before the blackout, more than 44,000 customers were still functioning without normal electric service that was lost as a result of Hurricane Maria. Up to a million customers have been without power since Hurricane Irma touched down Sept. 6 near Puerto Rico’s northeast coast.

The U.S. Army Corps of Engineers is overseeing the federal power restoration effort in Puerto Rico.

Tesla batteries are currently live & delivering power at 662 locations in Puerto Rico. Team is working 24/7 to activate several hundred more. https://t.co/OMu8qKJvLy — Elon Musk (@elonmusk) April 18, 2018

A company hired by Cobra Energy called Dgrimm was involved in the incident that caused the power outage, government officials said. After the blackout Wednesday, Dgrimm’s contract was terminated, said William Rios, a power generation director.

The entire island is set to have restored electricity by late May, officials said.

A group of federal legislators asked the U.S. Federal Emergency Management Agency to extend the the agency’s assignment beyond May 18 to ensure power is in fact restored to all island residents.

The Associated Press contributed to this story.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani