When Hurricane Maria slammed into Puerto Rico, it took down 80 percent of the transmission and distribution power lines, Puerto Rico Electric Power Authority CEO Ricardo Ramos told CNBC on Friday.
Power went down across the entire island after the hurricane made landfall as a Category 4 storm over a week ago. It was the most powerful storm to hit Puerto Rico in 90 years.
"We have started work. We are recovering slowly but we are recovering," he said in an interview with "Closing Bell."
He's anticipating that 50 percent of the power on the island will be restored in about two to three months.
In the beginning, the process will move quicker as areas that were less affected by the storm are identified and restored, Ramos said. Priorities are also being set, with power now back at 15 hospitals, he added.
"We're meeting the priorities but certainly this is a first stage. I think the second step that we're going to take now is going to be overwhelming," said Ramos.
That's why he's asking for help, especially since his employees have been working since Hurricane Irma hit earlier in the month.
Those workers are passionate and a "great bunch" but "certainly we will need some relief," Ramos said.
He's expecting help from private U.S. companies to arrive this weekend and start work early next week.