The Luzon grid was placed under its first yellow alert of the year on Thursday as outages across several power plants tightened supply during peak hours.

In an advisory, the National Grid Corp. of the Philippines (NGCP) said the yellow alert take effect from 4:00 p.m. to 10:00 p.m., with available capacity at 12,223 megawatts (MW) against a demand of 11,966 MW, leaving a thin operating margin.

A yellow alert is issued when reserves fall below the level required to cover contingencies, raising the risk of supply disruptions if additional plants go offline.

The tight supply was driven by widespread generation setbacks, with 35 power plants on forced outage and 14 others operating at reduced capacity, resulting in 5,137.2 MW unavailable to the grid.

Among the affected facilities were Ilijan Blocks A and B and Excellent Energy Resources Inc. (EERI) Units 1, 2, and 3, which experienced tripping incidents, while hydro units Magat 1 to 4 were also unavailable.

Responding to the situation, Energy Secretary Sharon S. Garin directed LNGPH—a consortium of San Miguel Global Power, AboitizPower, and Meralco PowerGen—along with other stakeholders to immediately restore the affected plants.

The Department of Energy said it remains under heightened monitoring and is implementing measures to protect power system reliability and minimize further disruption.

It also instructed NGCP, generation companies, and system operators to expedite the return of offline units, stabilize available supply, and prevent prolonged impact on consumers.

Although no power interruptions have been reported as of posting, the agency said it will continue to monitor the grid as demand remains elevated and supply conditions tight.