THE GRID OPERATOR placed the Luzon grid on yellow alert on Tuesday, the second straight day it has done so but for a longer period starting from 9:00 a.m. until 8:00 p.m.

The notice from the National Grid Corp. of the Philippines (NGCP) comes at a time when the country’s main island does not traditionally register high power demand, which usually peaks during the dry season.

Manila Electric Co. (Meralco) said it is ready to activate its interruptible load program, which relies on the private sector’s power generation sets to ease demand on the grid.

“This is due to insufficient operating reserve brought about by power plant outage,” Meralco said.

Meralco Public Information Office Head Joe R. Zaldarriaga said in case of supply deficiency, corporations and commercial establishments participating under the interruptible load program are ready to use their generator sets to help prevent or minimize incidents of power outage.

The power plants that went on unplanned outage are San Buenaventura Power Ltd.’s coal-fired power plant, which has installed and dependable capacity of 455 megawatts (MW). It went out on Nov. 25 and is expected to be back online on Nov. 27.

A day earlier, Quezon Power Ltd. Co. went on unscheduled shutdown. It has an installed capacity of 511 MW and a dependable capacity of 460 MW.

They added to plants that shut down earlier this month as scheduled: AP Renewables, Inc.’s Tiwi geothermal power plant unit 6, with installed capacity of 57 MW and dependable capacity of 50 MW; South Luzon Thermal Energy Corp.’s coal-fired power plant unit 2, with installed capacity of 135 MW, and dependable capacity of 122 MW.

In September and August, two plants that went offline have yet to be back: GN Power Mariveles Coal Plant Ltd., Co.’s coal-fired power plant unit 1, with installed capacity of 345 MW and dependable capacity of 316 MW; and Prime Meridian Power Corp.’s Avion natural gas-fired power plant unit 2, with installed capacity of 50.3 megawatts (MW) and dependable capacity of 48 MW.

On Monday, NGCP placed Luzon on yellow alert between 10:01 a.m. and 4:00 p.m. — Victor V. Saulon