Hurricane Fiona is now heading toward Bermuda and then eastern Canada as a major hurricane with winds of up to 130 miles per hour (215 kilometers per hour). The storm has killed at least eight people.
Fiona hit Puerto Rico five years after Hurricane Maria knocked out all power on the island in 2017.
Poweroutages.com, which estimates power outages based on utility data, said 1.033 million customers were without service early Thursday based on what it called limited information available from LUMA Energy, which operates Puerto Rico's grid.
There were roughly 1.168 million without power early Wednesday out of 1.468 million total customers, according to Poweroutages.com.
That pace of restoration is much faster than after Maria when almost all 1.5 million customers had no power for a week when the now bankrupt Puerto Rico Electric Power Authority (PREPA) was still operating the grid.
It took PREPA about 11 months to restore power to all customers, but Maria was a much more powerful storm than Fiona.
Maria hit Puerto Rico as a Category 4 hurricane with winds of 155 mph, while Fiona hit as a Category 1 storm with winds of 85 mph.
LUMA Energy said late Wednesday that it had restored service to nearly 376,000 customers. LUMA has said "full restoration could take several days."
LUMA is a joint venture owned by units of Canadian energy firm ATCO Ltd (50%) and U.S. energy contractor Quanta Services Inc (50%).
PREPA still owns much of Puerto Rico's power infrastructure. LUMA won a contract to operate the grid in 2020 and started managing that system in 2021.
(Reporting by Scott DiSavino; editing by David Evans)