Puerto Rico’s Fragile Power Grid Faces a Test With Tropical Storm Ernesto

(Bloomberg) -- Puerto Rico’s shaky power grid is facing its latest test with Tropical Storm Ernesto, which threatens to trigger widespread blackouts as it bears down on the island with gale-force winds and heavy rain.

Ernesto is expected to strengthen into a hurricane overnight as it passes northeast of Puerto Rico. While still about 60 miles (95 kilometers) away from the capital San Juan on the northern coast, it could bring up to 10 inches (25 centimeters) of rain and possible flash floods and mudslides to parts of the island facing the storm, according to the US National Hurricane Center. That will add to ground already soggy from multiple downpours in the last month, said Ryan Truchelut, president of commercial forecaster WeatherTiger LLC. 

“Heavy rainfall is expected to be the most widespread hazard,” Truchelut said. “Overall there are likely to be meaningful impacts,” including some localized wind damage.

Ernesto’s impacts are likely to be magnified on Puerto Rico because the island’s infrastructure has been pummeled by extreme weather events in the past few years. Hurricane Maria slammed into Puerto Rico in 2017, killing more than 2,900 people, causing about $90 billion in overall damage and leaving some residents without electricity for almost a year. The island experienced a full blackout again when Hurricane Fiona struck in 2022.

Puerto Rico’s 3.2 million residents suffer chronic outages even during calm weather because of the power grid’s vulnerability. They also pay some of the highest electricity rates in the US. Luma Energy, a US-Canadian consortium, manages the grid and is tasked with modernizing and strengthening the system’s infrastructure, but progress has been slow. 

Luma on Monday activated its emergency operations centers, mobilized more than 1,100 utility workers and is coordinating with mayors across the island and local and federal partners, Juan Saca, Luma’s chief executive officer, said in a press release.

“Storm-related outages are expected from Tropical Storm Ernesto, and we continue to urge all our customers and their families to take immediate actions, including preparing emergency supplies,” Saca said in the statement. “The safety of our crews and our customers will continue to be our highest priority.”

The Puerto Rico Electric Power Authority, which owns the grid, is still working through its seven-year bankruptcy. The prolonged process hinders the island’s ability to resolve the utility’s financial troubles and focus on rehabilitating its power infrastructure. A Prepa spokesperson referred questions to Luma, as it is the private operator of the grid.

Puerto Rico is already struggling to stabilize and fortify its grid, ramp up its renewable generation and strike a long-fought debt-cutting deal with bondholders and creditors, Sergio Marxuach, policy director at the Center for a New Economy, a San Juan-based think tank that focuses on the island’s finances and its energy challenges, said in an email.

“The real risk of tropical storm Ernesto is that it will further delay and complicate what already is a gargantuan undertaking,” Marxuach said.

More storms are likely to follow after Ernesto: US forecasters are predicting an explosive Atlantic hurricane season, with as many as 24 named storms, as warm ocean waters provide fuel for weather systems.

It isn’t clear if Ernesto will make landfall in eastern Puerto Rico overnight or simply come very close to the island, but there will be widespread heavy rain, said Alex DaSilva, a meteorologist at AccuWeather Inc.  

Puerto Rico’s roads, bridges and power grid are vulnerable after previous storms, he said. “The infrastructure is still recovering and it could impact them more than if they hadn’t been hit,’ DaSilva said.

Tides may rise one to three feet above normal along some of Puerto Rico’s coastline, as well as the US and British Virgin Islands, including St. Thomas, St. John and St. Croix, the US National Hurricane Center said in an advisory. Tropical storm warnings are posted on many of the islands, including Puerto Rico.

Ernesto is forecast to snake its way through the Caribbean, passing over parts of Puerto Rico late Tuesday into Wednesday and then churning into the Atlantic well east of the Bahamas. At that point it will start to strengthen as it makes a run north toward Bermuda, which it could hit Saturday as a Category 2 hurricane — or even a Category 3 — on the five-step Saffir-Simpson scale.

(Updates with latest conditions and position, according to National Hurricane Center, in second paragraph.)

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