SAN JUAN, Puerto Rico — Thousands of Puerto Rico residents remained without electricity Thursday morning, September 24, 2026, after a major grid disturbance the previous night knocked out power to more than 200,000 LUMA Energy customers, particularly across San Juan and Carolina.
At the height of the outage Wednesday night, LUMA’s outage data showed approximately 214,765 customers without electricity, including about 117,239 customers in the San Juan region and 92,655 in Carolina.
By Thursday morning, restoration work had substantially reduced the number affected. El Nuevo Día reported that more than 9,500 customers still lacked electricity as crews continued working to stabilize and restore the system.
Preliminary information points to an incident at the Sabana Llana transmission substation, between San Juan and Carolina, that affected both transmission infrastructure and multiple generating units.
What Caused the Puerto Rico Power Outage?
LUMA Energy said the event involved problems in both the generation system and the transmission and distribution network.
Energy officials reported that a series of failures began at approximately 8:11 p.m. Wednesday involving 115-kilovolt transmission infrastructure and the Sabana Llana Transmission Center.
The disturbance forced generating units at the San Juan and Cambalache power plants offline and also affected operations at the Palo Seco and Aguirre facilities.
LUMA spokesman Hugo Sorrentini said the company was investigating what happened and described the event as a disturbance affecting both generation and distribution.
The exact root cause remained under investigation Thursday.
Puerto Rico Power Outage Data
| Outage Detail | Latest Confirmed Information |
|---|---|
| Utility | LUMA Energy |
| Location | Puerto Rico |
| Main Areas Affected | San Juan and Carolina |
| Incident Began | Evening of September 23, 2026 |
| Peak Customers Without Power | More than 200,000 |
| Reported Peak | About 214,765 customers |
| San Juan Customers Affected at Peak | About 117,239 |
| Carolina Customers Affected at Peak | About 92,655 |
| Customers Still Out Thursday Morning | More than 9,500 reported |
| Primary Infrastructure Involved | Sabana Llana transmission facility |
| Generating Units Affected | San Juan, Cambalache, Palo Seco and Aguirre |
| Cause | Still under investigation |
| Restoration Status | Ongoing |
Fire Reported at Sabana Llana Substation
Images circulated Wednesday night showing flames at the Sabana Llana substation in Carolina.
Puerto Rico fire personnel responded to a fire at the facility, and local media published photographs showing flames at the site.
Early Wednesday-night reports were cautious about linking the visible fire directly to the system disturbance.
However, LUMA later said its preliminary assessment indicated that the event began at the Sabana Llana substation and affected generation units elsewhere on the grid.
The precise sequence of failures and what initially caused the equipment problem were still being investigated.
More Than 200,000 Customers Lost Power
The outage rapidly expanded Wednesday night.
At approximately 9:14 p.m., LUMA’s portal showed about 141,108 customers without service.
By around 9:50 p.m., that number had risen to 214,765 customers, with San Juan and Carolina accounting for most of those affected.
Other reporting placed the total above 217,000 customers during portions of the event.
Those differences reflect rapidly changing outage-map totals as circuits went offline and restoration work began.
LUMA Crews Work Through the Night
LUMA said field crews were responding to the affected infrastructure while personnel at the company’s control center worked to stabilize the transmission network.
The utility also coordinated with generating companies to return affected generating units to service.
LUMA said restoration would proceed safely and progressively as crews identified faults and brought the system back into a stable condition.
By Thursday morning, power had been restored to the vast majority of customers affected during the peak of the event.
Why Were San Juan and Carolina Hit Hardest?
San Juan and Carolina experienced the largest concentrations of outages because the incident involved major transmission infrastructure serving the metropolitan region.
At the peak reported by El Nuevo Día:
- San Juan had approximately 117,239 customers without power.
- Carolina had approximately 92,655 customers without power.
Transmission faults can affect customers well beyond the immediate location of damaged equipment because major lines and substations connect multiple generating plants, distribution circuits and population centers.
That helps explain why a problem centered around Sabana Llana could contribute to outages across a much larger section of the metropolitan electrical system.
Generating Plants Also Went Offline
The outage was not limited to neighborhood distribution lines.
Energy official Josué Colón Ortiz said Wednesday night’s transmission failures caused units at the San Juan and Cambalache plants to go offline and disrupted operations at Palo Seco and Aguirre.
Genera Puerto Rico personnel began stabilizing equipment at the San Juan and Cambalache plants so units could return to service.
Meanwhile, LUMA crews worked on the transmission faults.
This combination of generation loss and transmission problems contributed to the scale of the blackout.
LUMA Had Forecast Adequate Generation Capacity Thursday
LUMA’s September 24 system forecast showed approximately 3,280 megawatts of available capacity against an expected peak load of about 2,988 megawatts, leaving a projected reserve of roughly 292 megawatts.
Those figures represent systemwide generation availability and expected demand rather than a guarantee that every customer will have power.
Local transmission or distribution faults can still leave customers without service even when sufficient generation is theoretically available.
Were Selective Outages Also Used?
During Wednesday night’s disturbance, LUMA spokesman Hugo Sorrentini said the utility was also implementing selective outages, or load shedding, while attempting to stabilize the system.
Load shedding can be used when electricity demand temporarily exceeds available generation or when operators need to protect the wider grid from instability.
The duration and location of such interruptions can change quickly as generating capacity returns.
Is This a Puerto Rico-Wide Blackout?
No.
Although the outage affected more than 200,000 customers, it did not result in a complete island-wide loss of electricity.
The largest concentration of outages was in the metropolitan San Juan and Carolina areas.
Other regions continued receiving electricity during the event.
The distinction is important because Puerto Rico has previously experienced island-wide blackouts, whereas Wednesday’s disturbance affected a significant but smaller portion of LUMA’s roughly 1.5 million customers.
How to Check the LUMA Outage Map
LUMA maintains a public outage portal that provides information about interruptions affecting customers across Puerto Rico.
The utility says its service-update page includes interruptions affecting more than 500 customers and provides estimated restoration times when available.
Customers can also use LUMA’s website and mobile services to report outages and check service status.
Because totals change continuously during major incidents, outage-map numbers should always be treated as a snapshot rather than a fixed count.
How to Report a Puerto Rico Power Outage
Customers who remain without electricity can report their outage directly to LUMA.
LUMA lists its customer-service and emergency reporting number as:
1-844-888-LUMA (5862).
Residents should also report downed power lines or electrical equipment posing an immediate danger.
LUMA advises people to stay away from fallen electrical wires and avoid approaching locations where damaged equipment may still be energized.
Was the Outage Related to Planned Maintenance?
The major Wednesday-night outage was not described as planned maintenance.
LUMA separately publishes scheduled improvement projects that can temporarily interrupt service in specific communities.
Its September 24 planned-work schedule included projects in areas such as Ponce and Toa Alta.
Those localized planned projects are separate from the Sabana Llana system disturbance that affected more than 200,000 customers.
What Happens Next?
LUMA and energy officials are expected to continue examining the Sabana Llana equipment and system data to determine precisely what failed.
Investigators may review:
- transmission-line protection systems,
- electrical breakers and transformers,
- equipment at the Sabana Llana facility,
- operating data from generating plants,
- and the sequence in which generating units disconnected from the system.
The findings could help determine whether the initial failure occurred in transmission equipment, another electrical component or through a sequence of interconnected failures.
Final Puerto Rico Power Outage Update
As of the morning of September 24, 2026, Puerto Rico’s major overnight blackout was largely restored.
More than 200,000 LUMA Energy customers lost electricity Wednesday night, with the highest reported figures exceeding 214,000 and some reporting placing the peak above 217,000.
By Thursday morning, more than 9,500 customers remained without electricity, according to the latest local reporting.
Preliminary findings indicate the event began with failures involving the Sabana Llana transmission facility and affected generating units at several power plants.
LUMA said the system had been stabilized and restoration work was continuing.
The exact cause of the incident remained under investigation.
Frequently Asked Questions
How many customers lost power in Puerto Rico?
More than 200,000 customers lost electricity Wednesday night. One LUMA outage-map snapshot showed approximately 214,765 customers without service.
How many customers are still without power?
More than 9,500 customers remained without electricity Thursday morning, according to the latest available local report.
What caused the Puerto Rico outage?
Preliminary information points to an incident involving the Sabana Llana transmission facility that also affected multiple generating units. The root cause remains under investigation.
Was there a fire at the Sabana Llana substation?
Yes. Puerto Rico firefighters responded to a fire at the Sabana Llana facility, and photographs documented flames at the site.
Which areas were most affected?
San Juan and Carolina recorded the largest numbers of customers without power.
Was the entire island of Puerto Rico without electricity?
No. This was a major outage affecting more than 200,000 customers, but it was not a complete island-wide blackout.
How do I report a LUMA outage?
Customers can contact LUMA at 1-844-888-5862 and use the company’s outage portal to report and monitor service interruptions.
Disclaimer
This article reflects LUMA Energy information and Puerto Rico news reporting available on September 24, 2026. Outage totals can change rapidly as circuits are restored or new interruptions occur. More than 200,000 customers were affected at the height of the September 23 incident, while the number without service had fallen substantially by Thursday morning. The exact root cause of the Sabana Llana system disturbance remains under investigation, so no unconfirmed equipment failure or other explanation has been presented as final.