- Storm's impact would hit already stretched electricity infrastructure.
- Some areas of the island could have power back within a week.
- Irma is expected to cross Puerto Rico's northern coast.
Damages stemming from Hurricane Irma could leave parts of Puerto Rico without power for as long as six months, according to the Puerto Rico Electric Power Authority.
The Category 5 storm pummeled Caribbean islands, including Barbuda and Anguilla, before approaching Puerto Rico on Wednesday.
Irma is promising to be another prolonged challenge for the utility company, which is grappling with aged infrastructure after years of financial turmoil.
Ricardo Ramos, head of the utility company, known as Prepa, told local radio station NotiUno that parts of the island could be without power for between four and six months due to the poor state of the company's facilities.
The storm, one of the most powerful ever recorded, is packing maximum sustained winds of 185 mph. It is expected to travel near Puerto Rico's northern coast and could make landfall in Florida as early as this weekend.