The Luzon grid again went under a yellow alert on Wednesday due to supply constraints caused by the tripping of a gas-fired power plant.

In a report on Wednesday afternoon, the National Grid Corp. of the Philippines (NGCP) declared a yellow alert status across the Luzon grid from 3:00 to 9:00 p.m. 

The Visayas and Mindanao Grids, on the other hand, were under normal conditions.

Based on the initial report, the available capacity in Luzon yesterday was 13,198 megawatts (MW) while the peak demand was 12,028 MW.

NGCP said the tripping of the San Gabriel Plant located in the First Gen Clean Energy Complex in Batangas City was among the factors that contributed to the declaration of a power alert despite the cooler weather when demand is usually lower. 

417 MW taken off grid

The plant’s unforeseen shutdown slashed 417.4 megawatts (MW) from the grid, which brought the total unavailable capacity from forced plant outages to 1,358.7 MW.  

One plant had been on forced outage since last year, eight between January and May, and six power plants between June and July. Meanwhile, six plants were derated by 294 MW.

In total, outages and derated capacities accounted for a total of 1,652.7 MW of unavailable capacity, or equivalent to 9.32 percent of 17,734.840 MW total dependable capacity in the Luzon Grid.

In a separate statement yesterday, the Department of Energy said it is coordinating with the NGCP and other generation companies to manage the demand. 

“The Department is also urging electricity consumers to exercise judicious use of their electricity during this period to help manage the overall demand,” it said. 

A yellow alert is issued when the operating margin is insufficient to meet the transmission grid’s regulating and contingency requirements. When this status is in place, all power plants must run normally; otherwise, a red alert may be raised.