It took months to restore electricity in Puerto Rico after hurricanes dealt a one-two punch. Many homes are still without power, and the system’s future is far from certain.

A transmission tower and downed lines in the mountainous terrain of eastern Puerto Rico. Workers from the island and throughout the United States have worked to restore power after Hurricanes Irma and Maria last September.

A transmission tower and downed lines in the mountainous terrain of eastern Puerto Rico. Workers from the island and throughout the United States have worked to restore power after Hurricanes Irma and Maria last September. Todd Heisler/The New York Times

YABUCOA, P.R. — Rafael Surillo Ruiz was on the way to San Juan when he noticed that all the traffic lights had gone out. Mr. Surillo is the mayor of Yabucoa, among the first communities struck by Hurricane Maria last September, and for months he had been lobbying federal officials, local officials, utility officials — anyone who might help the thousands of his constituents still waiting to get their power back.

Now, as he headed north for yet another meeting, the phone calls from home confirmed the worst: Not only was his city of spiky mountains, lush green marshes and rugged coastline totally powerless again; the entire island was blacked out.

It was a rudely inauspicious omen, even for a man sunk seven months deep in frustration and disbelief.

“You have to understand that half our population still does not have power,” Mr. Surillo said the day after the April 18 blackout, recalling the morning after Maria when he emerged from his operations center to see the Yabucoa city hall devastated, houses smashed and downed power lines and poles littering the streets and countryside. The realization that the island has been left with such a flawed and fragile system after so much time and money spent on recovery, he said, “hurts in our hearts and souls as Puerto Ricans.”

After Maria and the hurricane that preceded it, called Irma, Puerto Rico all but slipped from the modern era. Even now, while officials say the $2.5 billion reconstruction effort has restored power to 98 percent of the grid’s customers, swaths of hilly country across the island are still pitch black after dark, punctuated by lights run on private generators. (About 60 percent of Yabucoa’s residents had power as of May 1.) Even restored sections of the grid are nightmarishly unreliable, as evidenced by last month’s outage, the second major power failure in a week and the fourth since early February.

Yasmin Morales Torres standing in what was left of a relative’s home in Yabucoa. In the storms’ devastation, the island all but slipped from the modern era. Todd Heisler/The New York Times

On the mainland, much of the coverage of the recovery has focused on the struggles of the island’s beleaguered power authority and its politically disastrous hiring of Whitefish Energy Holdings, a tiny and inexperienced Montana contractor linked to the Trump administration’s interior secretary. Here in Puerto Rico, the perception of a condescending and under-responsive government in Washington has been fed by the enduring image of President Trump seeming to minimize the catastrophe while tossing paper towels into a crowd.

But an examination of the power grid’s reconstruction — based on a review of hundreds of documents and interviews with dozens of public officials, utility experts and citizens across the island — shows how a series of decisions by federal and Puerto Rican authorities together sent the effort reeling on a course that would take months to correct. The human and economic damage wrought by all that time without power may be irreparable.

When the Puerto Rico Electric Power Authority, known as Prepa, hired Whitefish for the reconstruction, it also declined to request direct assistance from mainland utilities that for decades had routinely dispatched workers to help one another recover from disasters large and small.

At the same time, the Federal Emergency Management Agency made a highly unusual decision of its own. Rather than advise Puerto Rico to accept aid from the mainland utilities, FEMA abruptly called in the Army Corps of Engineers — never mind that the corps had never rebuilt a major grid after a storm and by its own account had not made preparations to take on the task in Puerto Rico.

The result was a chaotic tangle of overlapping missions and fumbling coordination.

Compounding those problems, the grid was decrepit, corroded and poorly maintained, and Prepa — which, like Puerto Rico as a whole, is effectively bankrupt — had failed to keep sufficient stocks of replacement parts and other critical supplies. Shipments of parts from the mainland were slow to arrive and languished in the battered ports. The terrain is so forbidding that replacing a single power pole can require a helicopter and a team of line workers. The effort seemed to go impossibly awry.

“I’ve never seen anything like that — not in a developed nation,” said Ed Muller, a former energy executive whose generation and transmission equipment suffered flooding by Hurricane Sandy in New Jersey, severe storm damage in Jamaica and earthquakes in California. In the Caribbean, he said, “hurricanes come through regularly, and have forever. You move people in and you get it done. And we haven’t done it.”

Many experts and public officials have also lamented the decision, largely driven by federal disaster-assistance law, to rebuild a poorly designed grid almost exactly as it was. “The system that we have up now in Puerto Rico is vulnerable to a hurricane, and it’s going to happen again,” said Rolando Ortiz Velázquez, the mayor of Cayey and head of the Mayors Association of Puerto Rico.

Palo Seco is a major power plant in the San Juan area. Like much of the electrical system, it is in a state of disrepair. Todd Heisler/The New York Times

It took more than a month for Prepa’s decision on aid from utilities, known as mutual assistance, to be undone. In late October, with the reconstruction seemingly stalled, Gov. Ricardo A. Rosselló of Puerto Rico met with Gov. Andrew M. Cuomo of New York, a veteran of Hurricane Sandy and other natural disasters. Mr. Cuomo strongly recommended invoking mutual aid.

Weeks more would pass before the full mobilization got underway, but beginning in November, the first of some 3,000 utility workers from across the country began pouring in. The first wave had a distinctly New York flavor — San Juan streets filling with trucks and workers bearing the insignia of Con Edison, the New York Power Authority and other organizations. Carlos D. Torres, Con Edison’s recently retired storm and emergency czar, became Mr. Rosselló’s choice to lead the restoration and reshape the effort.

After the ferocity of Maria, there has been a whirlwind of blame cast among the parties involved.

“Bad, very bad,” Mr. Ortiz said when asked for his judgment of a program that, he said, repeatedly reneged on promises and timelines. “They have not listened to the communities, and they have not told them the truth.”

Pretty much everyone spoke of Maria’s awesome power and the extreme challenges posed by Puerto Rico’s precipitous landscape.

Prepa’s new chief, Walter Higgins, said that he was communicating with unhappy municipalities, but that the catastrophic damage in mountainous terrain made the job “more difficult than any other restoration ever experienced in Puerto Rico, perhaps anywhere.”

For its part, FEMA said its effort had moved rapidly, though it conceded that the final pieces — the “last mile” — were especially challenging.

To Mr. Torres, who speaks with the wisdom of many storms, the human forces at work in Maria’s wake were at least as daunting as the natural ones.

“I tell you, I thought Sandy was the worst storm of my life,” Mr. Torres said. Compared with Maria, it turned out to be “a cake walk,” he said, adding, “There are a lot of complexities here that are far beyond what Sandy was.”

Thousands of miles of power lines, often stretching across high-altitude areas, were downed or damaged. By Tim Chaffee and Veda Shastri

The Corroding Grid

As Maria approached before dawn last Sept. 20, Cecilio Ortiz Garcia had a premonition of what was to come. Dr. Ortiz is a professor at the University of Puerto Rico’s campus in Mayagüez, and for the last few years, he and his colleagues had been studying the long decline of Prepa and its electrical grid.

“When Maria came,” Dr. Ortiz said, “she found a system that was already on its knees.” By 5 a.m., nearly every light on the island was out.

The electrification of the entire island began only in the late 1800s, when sugar and tobacco barons began allowing local municipalities access to their power systems, Dr. Ortiz said. Luis Muñoz Marín, the activist who became the island’s first elected governor in 1948, built up the grid and made it the industrial pride of Puerto Rico. By the late 1950s, helicopters were ferrying power poles to the island’s remotest corners.

The slide began with Mr. Muñoz’s defeat in 1968. Since then, Dr. Ortiz said, the island’s two pre-eminent political parties have made Prepa more a patronage bank than a center of technical excellence — a view shared by some who have grappled with Prepa from within. Juan F. Alicea Flores, a former director, recalled that whichever party was in power would hand over an organizational chart filled with politically connected people.

“ ‘You are the leader, but the team is ours,’ they would say,” Mr. Alicea said, recalling the negotiations he endured.

Prepa suffered another blow after building oil refineries and fossil fuel power plants, many on the southern coast — only to see the 1973 oil crisis pummel the island financially for making those bets. More recently, a series of poorly advised bond issues left the authority bankrupt, $9 billion in debt.

Vines crawling up a transmission tower. The power grid has been in decline for decades, and much of the infrastructure is in hard-to-reach areas. Todd Heisler/The New York Times

As a result, the plants in the south have become what Dr. Ortiz called a “cemetery of rust.” Conducting wire carried by aging transmission towers must hopscotch forested mountain ranges to carry power to the densely populated San Juan area in the north. That leaves the towers, and therefore the entire system, extremely vulnerable to high winds.

Performing inspections after Maria, utility experts observed what had become of Mr. Muñoz’s achievement. The “deadman anchors” — concrete-encased steel rods — attached to the guy lines holding up transmission towers had corroded, according to Jeffrey A. Miller, an engineer for the federal Energy Department. While other utilities that use those anchors have protocols for regular inspections and repair, Prepa did not, he said.

“Given the age of the system as a whole, it’s not a stretch that that was a culprit in the majority of the transmission lines that fell,” Mr. Miller said, adding that the high winds were a factor as well.

A recent tour of the major power plant in the San Juan area, Palo Seco, revealed a grimy, corroded mess, with grand old turbines opened up and rusting, like someone’s forgotten auto repair project on a front lawn. Local distribution systems were no better. Linemen found incomprehensible snarls of wiring and defunct equipment perched atop rotting wooden power poles.

During the Palo Seco tour, Prepa’s executive sub-director, Justo González, said a recent restructuring forced on the utility because of its debt had focused largely on financial restrictions. “They forgot about the maintenance,” he said. (Mr. Higgins, the new Prepa chief, said that maintenance of Palo Seco was now in the budget, and that the authority was “carrying it out.”)

Blue tarps from FEMA still cover damaged roofs awaiting repair in southeastern Puerto Rico. By Tim Chaffee and Veda Shastri

No Call for Mutual Aid

As unpredictable as major storms are, the utility industry has a standard bag of post-disaster tricks. Because every utility knows that it may need help next, there is seldom a problem mustering enough workers via mutual aid. Some 10,000 workers from 21 states traveled to Texas and Louisiana after Hurricane Harvey last summer, according to the Edison Electric Institute, an industry group. And after the one-two punch of Irma and Maria, the United States Virgin Islands took the standard step of bringing in a contractor and about 800 mainland utility workers.

Indeed, a range of experts, including officials from the principal industry groups, said they could not recall an instance in recent decades of a utility failing to request mutual aid after a grid was knocked out in a major storm.

In Puerto Rico, “mutual aid should have been one of the first things they did,” said James Lee Witt, who ran FEMA during the Clinton administration.

How large was the task? Puerto Rico has 2,400 often mountainous miles of high-voltage transmission lines, 342 substations and 30,000 miles of lower-voltage distribution lines that go to neighborhoods and homes, according to Prepa. Maria damaged 80 percent of that system.

But on Sept. 28, eight days after Maria made landfall, two parallel decisions drove the monumental rebuilding into uncharted territory.

In a conference call with Prepa, government and utility officials delivered a collective offer of mutual aid: “We stand ready to help you,” they said, according to Mike Hyland, a senior vice president at the American Public Power Association, who was on the call. But the Prepa officials, he recalled, said they were hiring Whitefish to restore the entire system.

Line workers from New York and Wisconsin utility companies gathered for a safety meeting at dawn in San Juan. Todd Heisler/The New York Times

With that, Prepa placed its chips on a tiny company with hardly any full-time employees. “None of us had ever heard of Whitefish before,” said Jonathon Monken, an Army reservist who had been called to duty in a FEMA operations room in Washington and is senior director for system resiliency at PJM Interconnection, which runs power grids in multiple states. “Like, who?”

At the same time, FEMA made its own request, enlisting the Army Corps to provide emergency repairs to the grid.

FEMA had already given the corps a task it routinely performed: bringing in emergency generators for hospitals, clinics, town centers and other facilities. By all accounts, those measures were carried out successfully.

But the corps “has never repaired an electrical power grid of this magnitude as part of a domestic disaster response,” said its commander, Lt. Gen. Todd T. Semonite. Although it had placed “a small contingent” in Puerto Rico before Maria to assess eventual damage, he added, the corps “could not predict” the assignment to restore the grid.

FEMA and the corps both said they had had no hand in Prepa’s decision to hire Whitefish. Asked why FEMA had brought in the corps, Lea Crager, a FEMA spokeswoman, said, “Due to the magnitude of this storm and the devastation caused to the grid, we knew repair and rebuilding of the grid would take a joint effort.”

The political brouhaha ignited by the Whitefish hiring vastly complicated matters. Initially, questions focused on Ryan Zinke, the interior secretary, whose hometown is Whitefish, Mont., where the company is based. Mr. Zinke and the company itself said he had nothing to do with awarding the contract, even though his son worked a summer job at Whitefish. Beyond questions about Whitefish’s capability, the uproar was magnified by the opaque wording of the $300 million contract, the size of the company’s markups and a Twitter threat to withdraw from San Juan after criticism by the mayor. Whitefish soon apologized.

Ricardo Ramos, Prepa’s director at the time, has made a series of disparate statements about why the authority did not invoke mutual aid.

“It was always my intention to call upon them,” Mr. Ramos said in a recent interview.

A decades-old generator at Palo Seco, a crucial station in the island’s power grid. Todd Heisler/The New York Times

But until they receive reimbursement from FEMA, utilities often must pay for things like workers’ food and housing via mutual aid. In October, Mr. Ramos told The New York Times that he had not wanted to exhaust Prepa’s emergency funds paying mutual-aid groups while waiting for reimbursement. (Mr. Trump had declared that FEMA would provide full reimbursement for emergency work in Puerto Rico. Whitefish, though, said it was not requiring payment up front.) Mr. Ramos also said that Prepa would have been hard-pressed to provide the workers with hotel rooms, food, fuel and other supplies.

Mr. Ramos said he had no regrets. Mr. Roselló, however, acknowledged that his government had fallen short — that it should have had “some sort of agreements already in line,” as well as a “rainy-day fund” for mutual-aid payments.

“That is one of those lessons learned,” he said.

A Response in Slow Motion

Whatever was or was not said and done, the overlapping duties, without the experienced utilities that had coordinated and carried them out through decades of storms, seemed to be a prescription for chaos. That, by many accounts, is exactly what followed.

In practice, all the players answered to Prepa, according to Mr. Miller of the Energy Department.

The lights of San Lorenzo can be seen from the hilltop home of Sylvia and Reggie Martínez. They have been living without power since Hurricane Irma. Todd Heisler/The New York Times

“Prepa was trying to manage the overall restoration process,” Mr. Miller said, but “they would work on a line and not finish it.” The authority, he added, “had the appearance of not knowing what was going on, but jumping from point to point and putting out spot fires, so to speak.”

In the first days, as Prepa officials struggled in the mud and darkness to begin the journey back to a functioning grid, it turned out that the authority had not even stockpiled enough gasoline to see it through the emergency.

“We spent five or six days just scrambling to get gas,” Mr. González said, “reaching out to gas stations to make special arrangements for our employees. It was a battle.”

Ángel R. Figueroa Jaramillo, president of the Electrical Industry and Irrigation Workers Union, said he found rudderless teams of Prepa workers waiting for orders. “There was no work,” he said. “The men were standing around for two days waiting to find out what to do.”

Mr. Higgins, the new Prepa chief, said, “Prepa has an emergency plan and employees know it.” Once the storm had passed and communications were established, he said, “every effort was made to make the best use possible of every person.”

For its part, the Army Corps moved as swiftly as federal regulations allowed, General Semonite said. But even after invoking emergency measures to speed the effort, he said, it was not until Oct. 19 that the corps awarded the second of two major restoration contracts. The contractors, in turn, had to scout the damage before work could begin.

Mildoel Rodríguez, who is disabled, relied on candles to see in his home after dusk until power was restored last month. Todd Heisler/The New York Times

By February, crews with the corps’s main contractor, Fluor, had started returning home amid criticism in some quarters that the work had gone sluggishly. Fluor has defended its work.

Mr. Rosselló said the corps’s bureaucracy was all but immovable in an emergency that demanded quick action.

“They didn’t have a sense of urgency; there was always a bureaucratic excuse for one thing or another,” he said.

In his communications with mayors, Mr. Torres, the retired storm czar who became the governor’s lieutenant, said delayed deliveries of millions of parts — the Pentagon’s responsibility — often slowed power restoration in those desperate communities.

Maj. Catalina Carrasco, a spokeswoman for the Army Corps, said she was aware of the governor’s concerns, adding that the Corps had made clear from the start that the effort would be lengthy because of “the extensive damage caused by the two hurricanes, the challenges of terrain, the state of the grid system before the storms and the long distance restoration matériel must travel to the island.”

The work was further complicated by the strictures of federal law. The Stafford Act, which governs FEMA reimbursements, in most cases requires rebuilding to pre-disaster specifications. In Puerto Rico, that meant recreating electrical components that gave the impression of a time capsule from the 1950s and ’60s. In some cases, like an outmoded transmission cable called the Puerto Rican Special, the parts had to be rebuilt from scratch, Mr. Miller said.

The sense of spinning in place was summed up by the experience of 20 workers from Lakeland, Fla., hired as subcontractors by Whitefish. The workers arrived expecting to pick up their trucks, which had left Florida 10 days earlier. “Every morning I waited for the call to pick up the trucks,” Charlie Russell, the Lakeland Electric supervisor on the ground, wrote to his bosses.

A crew from Oklahoma Gas and Electric repairing a pole. Some 3,000 utility workers from across the country assisted in the restoration effort. Todd Heisler/The New York Times

He waited and waited. Puerto Rico’s damaged ports, shut down after the storm, were now jammed with a backlog of containers.

Mr. Russell asked at his hotel for the location of Prepa’s offices, where he might get some answers. He set out on foot with a Spanish-speaking co-worker to a district office two miles away. They found it, but security guards would not let them in. They tried again the next day. Eventually he found a Prepa supervisor, but he had no tasks for the men.

In the end, Lakeland Electric was in Puerto Rico for 22 days. The crew did repair work for two and a half. The bill, which taxpayers will probably foot: $820,271.25.

Turbines lay destroyed in Punta Lima. This wind farm is one of the few sources of renewable energy on the island. By Tim Chaffee and Veda Shastri

The Island Adapts

As time slipped away, people settled into new routines without electricity.

In the hills above downtown San Lorenzo, Sylvia Martínez woke at 3:30 a.m. every workday, heated water on the gas stove and carried it to her bathroom in a pot so she could shower — using a plastic cup — before her long commute to San Juan. She developed an affection for easy-to-make meals of Cheez Whiz and crackers. Mildoel Rodríguez, who is disabled, relied on candles to see as dusk settled in among the dizzyingly steep hills on the outskirts of Cayey. In Humacao in the east, Luz Rivera conducted Bible study classes with her friends by flashlight.

Some who could afford it took to paying unauthorized workers to climb the poles, connect the lines and bring power to houses and neighborhoods. In San Juan, Alejandro Cubiñá paid a worker $500 to fix the lines powering his business, a tree nursery. “That’s the Macondo way,” Mr. Cubiñá said, referring to the hidden factors at work in the city of that name in “One Hundred Years of Solitude,” by Gabriel García Márquez.

Mr. Ortiz, the Cayey mayor, began organizing unofficial workers, including former Prepa employees, to hook up his desperate city, but he ignored an unspoken Macondo rule: Rather than keep the work secret, he informed Prepa. The authority shut the effort down, citing safety issues, he said.

It was against this backdrop of scant visible progress that Mr. Rosselló met with Mr. Cuomo in a back room at the San Juan convention center on Oct. 26, more than five weeks after the storm.

Ms. Martínez lighting her stove at dusk. After the power went out, she began heating water on the stove so she could shower — using a plastic cup — before heading to work in the morning. Todd Heisler/The New York Times

Mr. Rosselló was accompanied by a handful of his top emergency officials; Mr. Cuomo had brought along two top aides and Gil C. Quiniones, chief executive of the New York Power Authority. Mr. Ramos was not there.

The Puerto Rico governor expressed frustration and repeated what everyone knew: Despite a swarm of federal officials and contractors having arrived to help, power was still almost completely out across the island.

In a recent interview, Mr. Cuomo — who is seeking a third term — deflected suggestions that his involvement in the recovery was meant to cultivate political capital. Rather, he said, he was motivated by cultural and personal connections with the large number of Puerto Rican New Yorkers.

Even so, storms — or, more precisely, the way public officials deal with them — are unmistakably political, especially in New York, where the failure to clear city streets after a 1969 blizzard famously crashed Mayor John V. Lindsay’s rising political star. For his part, Mr. Cuomo has generally received far higher marks for his handling of Sandy and other storms.

Mr. Cuomo pointed out in the interview that he and Mr. Rosselló shared a bond dating to an earlier storm: In his office, Mr. Cuomo keeps a picture of himself huddling in a shelter with Mr. Rosselló’s father, Pedro, then Puerto Rico’s governor, during Hurricane Georges in 1998, when Mr. Cuomo was federal housing secretary.

Workers securing a pole that a helicopter lowered into place in the mountains of San Germán. Todd Heisler/The New York Times

Now Mr. Cuomo urged Mr. Rosselló and his colleagues to invoke mutual aid. For Mr. Rosselló, a professor of biomedical engineering who had taken office just a few months before, “this was a case of first impression,” Mr. Cuomo explained.

“They say: ‘O.K., one question,’ ” Mr. Cuomo recalled. “ ‘What is a request for mutual aid?’ ”

Then, using Sandy as an example, Mr. Quiniones laid out how Long Island power officials had requested mutual aid and received nearly full reimbursement from FEMA for the immediate restoration.

At that point, Mr. Quiniones said, Mr. Rosselló signed on.

Not long after, Mr. Rosselló demanded Whitefish’s ouster and Prepa terminated the contract. Whitefish stayed to finish work that included repairing five transmission lines, which a company spokesman says was successfully done. Whitefish filed papers in federal court to recover more than $100 million that it said it was still owed.

Precarious Progress

The black-and-yellow helicopter appeared over a ridge to the south. Beneath it was a 35-foot length of pine — a power pole — dangling from 100 feet of rope. The pilot, Andrew Chan, of Portland, Ore., flew northward along an ascending mountain valley toward a bare outcropping where utility workers were waiting next to a partly trampled barbed-wire fence, a downed power pole and a pink tin-roofed house.

Julie Angulo Ramos, of San Juan, danced after her home got power in February. As she ran to switch on appliances, her friend pulled a string to turn the kitchen light on and off repeatedly. Todd Heisler/The New York Times

The steep gravel-and-concrete lane leading to the house in San Germán, in western Puerto Rico, was too treacherous for a heavy vehicle. Which was why Mr. Chan was lifting the load up the heavily forested valley and past the pink house, pivoting 180 degrees and slowly approaching the workers — their hard hats tilted upward, the aircraft bobbing and pitching slightly in the wind.

Mr. Chan lowered the pole toward a hole in the dirt as Ron Overbye and Brock Stigall of Greensboro, N.C., yanked on guy lines until the pole was in place. Using a controller in his left hand, Mr. Chan disconnected the rope and flew southward again, disappearing over the ridge to pick up a second pole and then the conducting wire to string between them.

In all, it would take 18 workers — from an Army Corps contractor called PowerSecure — a full week to light up about 30 houses in this unforgiving terrain, said Maj. Michael Meyer, a corps spokesman. And these were just two of over 41,000 power poles that the Army Corps says it has shipped, using the Pentagon’s Defense Logistics Agency, along with 4,545 miles of conducting cable and wire and 36 million repair parts.

After Prepa’s request for mutual aid on Oct. 31, the various parties in the effort began trying to make up for lost time. Mr. Torres arrived in San Juan in early November and, working with Prepa and the Army Corps, set up a control room, placed management teams in seven regions of the island and unified the command structure.

By Nov. 17, the New York contingent had begun powering up citizens in San Juan. (Mr. Ramos, under pressure over the Whitefish hiring, resigned that day.) By early January, after the mutual aid paperwork was ironed out, workers had arrived from Florida, Illinois, Kentucky, Maryland, Michigan, Ohio, Oklahoma, Texas, Wisconsin and elsewhere.

Children celebrated after workers restored power to their school in San Juan. Todd Heisler/The New York Times

Ahsha Tribble, FEMA’s deputy administrator for the region that includes Puerto Rico, said the agency had made “unbelievable progress,” adding that “by late April, 78 percent of the transmission has been energized, as we continue to support Prepa in the emergency work to restore power.”

Still, the shadow of the Stafford Act hangs over the entire effort. In the work done so far, the new lines, like the old ones, will stand on exposed ridges to carry power over the mountains from south to north. Despite years of demands from environmental and industrial groups, new solar farms that would wean the island from fossil fuels and power more resilient local grids will remain largely unbuilt.

The government’s bullish figures aside, how far along is the power restoration? With the continuing blackouts, and nearly 900 temporary generators still on the island, according to congressional testimony, it is hard to gauge the true state of the grid or how lasting the fixes will be.

Mistakes by contractors overseen by Prepa have triggered the island-wide blackouts: a tree being cut down to clear the way fell into a live line, a conductor left dangling in the mountain wind shorted out and a piece of equipment too close to another line caused another short. In the fourth case, a component at the Monacillos substation in San Juan overloaded and caught fire. Because the system still lacks enough backup lines and generators, each fault shut down most of the grid.

What is undeniable is that when utility trucks from the mainland finally arrive in a neighborhood, there is joy. In February, on Buenos Aires Street in San Juan, a crowd gathered at Julie Angulo Ramos’s home as a group of utility workers from WEC Energy Group in Wisconsin rounded the corner, ready to power the street. One of them, Josh Blankenberg, went up in a bucket and connected the leads at the top of a pole. The street lit up. People shouted, prayed, danced, whistled.

“Thanks to God! Thanks to you!” Ms. Angulo shouted to the workers.

For others, that moment took longer to arrive. Workers from Commonwealth Edison in Chicago hooked up the home of Mildoel Rodríguez, in Cayey, and the surrounding neighborhood during the first days of April. Others are still waiting. Ms. Rivera, in Humacao, does not have power and has heard nothing from Prepa or the local government.

At 3:30 each workday, Mrs. Martínez wakes to prepare for her long commute to San Juan, on a route where many traffic lights lack power. She has taken to making easy meals of Cheez Whiz and crackers. Todd Heisler/The New York Times

And in San Lorenzo, after her breakfast of Cheez Whiz and coffee, Ms. Martínez still carries hot water from her stove to the shower in a three-gallon pot. Then she drives to work in the predawn, the Big Dipper visible in the sky above the dark hilltop.