A series of plant outages pushed the Luzon grid to a yellow alert, but Department of Energy (DOE) data showed that Prime Infrastructure Capital Inc.’s natural gas facilities played a crucial role in stabilizing the system.

The government data showed that as the system reeled from the sudden loss of supply, oil-fired plants providing ancillary services were quickly dispatched to stabilize grid frequency. These included Limay CCGT, TMO Navotas, Bulacan Power Gen (Trans-Asia), Ingrid, and Subic.

An additional output from Bauang oil plants, along with natural gas and coal-fired facilities, was also ramped up later in the day to meet demand.

Prime Infra’s gas plants—operated by subsidiary Prime CoreGen—ran at about 95 percent capacity to help cushion the impact on the grid. These facilities include the 1,000-megawatt (MW) Sta. Rita plant, the 450-MW San Gabriel plant, and the 97-MW Avion plant.

The disruption began when several major generation units—including Ilijan Blocks A and B and Excellent Energy Resources, Inc. Units 1, 2, and 3—tripped offline.

In response, Energy Secretary Sharon Garin directed their operators, a joint venture involving San Miguel Global Power, Aboitiz Power, and Meralco PowerGen, to restore the affected facilities immediately.

The outages pushed Luzon into its first yellow alert of the year, as demand peaked at 11,966 MW against an available capacity of just 12,223 MW.

At the time, 35 power plants were on forced outage, while 14 others were operating at reduced capacity, leaving over 5,100 MW unavailable.

The grid operator attributed the tight supply to outages in key Batangas gas plants and limited hydroelectric generation.

The situation extended beyond Luzon, with the Visayas grid also placed under a one-hour yellow alert later that evening.

Available capacity there stood at 2,597 MW, only slightly above the demand of 2,368 MW, partly due to reduced power imports from Luzon.

A yellow alert is issued when reserves fall below the required contingency level.

Despite the strain, the system stabilized relatively quickly. Manila Electric Co. reported that power was restored after a brief imbalance that lasted only around 10 to 15 minutes.

The DOE said it remains on heightened monitoring and has instructed the National Grid Corp. of the Philippines, along with generation companies and system operators, to accelerate the restoration of offline units and prevent further disruptions.