Updated Sept. 26, 2017, 2:45 p.m. EST

(Bloomberg) -- A nursing home in San Juan made desperatepleas for diesel as its power generator ran low.

An elderly man was carried out on a stretcher after going a weekwithout dialysis.

Children wearing nothing but diapers camped out on balconies tostay cool.

This is Puerto Rico’s hottest time of the year — and nextto nobody has air conditioning. Hurricane Maria, which smashed into the island sixdays ago and devastated the power grid run by Puerto RicoElectric Power Authority, couldn’t have struck at a worse time.

Crews have descended upon the island to begin the arduous taskof resurrecting what was an already aging and long-neglectedsystem. But that’ll take weeks, if not months — meaning moresleepless, summer nights for those like Juan Bautista Gonzalez.

'It's brutal'

“It’s brutal,” said Gonzalez, a 36-year-old carpenter who wassitting on a stoop in Old San Juan rubbing his forehead infrustration. “No one can sleep. I spend all night tossing andturning. This is chaos.”

The destruction that Maria exacted upon Puerto Rico’s fragileelectricity system when it slammed ashore as a Category 4 storm — notjust for the island but for all of the U.S. More than half of theterritory’s towers may be down, at least 90% of its distributionlines damaged or destroyed and almost all overhead transmissionlines affected, according to the American Public Power Associationand Energy Department.

All told, Maria could end up resulting in $40 billion to $85billion in insured losses across the Caribbean.

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In the 32 years that National Guard brigadier generalWendul G. Hagler II has served, he said, “It’s about as large ascale damage as I have ever seen.” Hagler had visited the U.S.Virgin Islands just before Maria hit.

For an indication of how long it’ll take for Puerto Rico torebuild the system, Governor Ricardo Rossello points to HurricaneHugo, a powerful storm that ravaged the region in 1989. Somehad electricity within two months of Hugo. Others spent six monthswaiting. “It’s a gradual thing," Rossello told reporters on Sunday.“You have to be careful not to alarm people.”

The lack of phone and internet access isn’t helping. PuertoRicans pulled over along highways over the weekend to takeadvantage of the rare spots where cellular service was available.They called into the few radio stations still working in an attemptto connect with relatives.

Yashira Gomez, president of La Perla community board showspart of the devastation left by Hurricane Maria, in San Juan,Puerto Rico, Monday, Sept. 25, 2017. The island territory of morethan 3 million U.S. citizens is reeling in the devastating wake ofHurricane Maria. (AP Photo/Carlos Giusti)

Dam still at risk of bursting

To make matters worse: Puerto Rico’s power plants seem inexplicablyclustered along the island’s south coast, a hard-to-reach regionthat was left exposed to all of Maria’s wrath, said Kenneth Buell,a director at the U.S. Energy Department who is helping lead thefederal response in Puerto Rico. A chain of high-voltage linesthrown across the island’s mountainous middle connect those plantsto the cities in the north.

Related: Hurricane Irma's damage throughout the Caribbean[photos]

Puerto Rico’s rich hydropower resources have also taken a hit.On Friday, the National Weather Service pleaded for people toevacuate an area in the northwest corner of the island after a damfailed. The rest of the dam is still at risk of bursting.

And that’s not to mention the state of Puerto Rico’s grid beforethe storm. Government-owned Prepa, operating under courtprotection from creditors, has more than $8 billion in debt butlittle to show for it. Even before the storm, outages were common,and the median plant age is 44 years, more than twice the industryaverage.

As long as 2 years to rebuild network

"Under normal circumstances, without an emergency,” Rossello said,it would’ve taken Prepa as long as two years to rebuild itsnetwork. “And that’s being aggressive,” he said.

At this point, the National Guard is looking to clear enoughdebris for utility workers to move around. Almost 1,400 NationalGuard personnel are involved in the response in Puerto Rico, movingfood and water, helping local law enforcement and supplyingengineering support to access infrastructure.

Restoration crews’ biggest priority will be to restore power toessential services — the airport, water infrastructure andhospitals, Buell said.

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It won’t be easy. The supply chains the island once relied on toshuttle fuel oil and natural gas to generators, supplying the vastmajority of the island’s power, have been destroyed. The Energy Department was looking for alternative sources.Some agencies are capable of flying in fuel, and the government maywaive a law that limits the tankers permitted to haul oil andliquefied natural gas between U.S. ports.

Once critical resources have regained power, crews will startthe long process of getting power plants back online and rebuildingtransmission and power lines.

Port capacity

And while there are enough U.S.-flagged vessels to delivercommodities, “the limitation is going to be port capacity tooffload and transit,” the Department of Homeland Security saidby email Monday. Over the weekend some ports had reopened withrestrictions.

U.S. Representative Adam Smith of Washington, the rankingDemocrat on the House’s Armed Services Committee, blasted the Trumpadministration’s response on Monday as being “wholly inadequate”and called on the White House to assemble a coordinated militaryeffort similar to one organized after Hurricane Katrina.

“A territory of 3.5 million American citizens is almostcompletely without power, water, food, and telephone service,”Smith said. “It’s a disgrace.”

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