Much of the Sunshine State remains in the dark.

More than 5.6 million homes and businesses in Florida — about 54 percent of the state — were without electricity Tuesday morning as a result of Hurricane Irma, officials said.

The number of customers without power was down from a peak of about 6.5 million Monday — but each account usually represents more than one person.

About 15 million people — about two-thirds of Florida’s population — were without power, according to Christopher Krebs, assistant secretary for infrastructure protection at the Department of Homeland Security, the Washington Post reported.

Authorities said people could be without electricity for a week or more during what they described as the largest restoration process in history, the Orlando Sentinel reported.

Utility companies were still assessing before giving a more specific timeframe.

“Our crews are working as quickly and safely as possible to assess damage to our system and restore power,” Orlando Utilities Co. said on its website. “We are focusing on restoring power to feeders that serve critical customers like hospitals, wastewater plants, fire, and police.”

OUC had about 95,000 customers without power.

Duke Energy, meanwhile, has 9,000 workers trying to restore electricity.

“We will not stop until we get everyone back on,” Duke Energy Florida president Harry Sideris said in a statement.

Federal Emergency Management Agency director Brock Long told reporters he was traveling to Puerto Rico and the US Virgin Islands to meet with their governors Tuesday.

“Obviously, power restoration is one of the biggest goals,” he said.

The unprecedented outages unleashed a domino effect across the region as crews struggled with downed lines and a storm-swamped electrical grid.

Electrical power also was needed to keep water and sanitation systems operating.

And for those with a generator, fuel supplies depended on the ability of a logistical network to keep gas flowing across Florida.

“Power pretty much drives everything,” Krebs said.