THE National Grid Corp. of the Philippines (NGCP) issued a yellow alert over the Luzon grid on Thursday after five power plants experienced forced outages while three others were operating at less than their rated capacities.

The NGCP initially raised the yellow alert for the 1 p.m. to 8 p.m. period. The grid operator said capacity available was 11,166 megawatts (MW) while peak demand was 10,455 MW.

The NGCP said that a total of 2,115 MW worth of power was rendered unavailable to the grid.

The grid operator lifted the alert at 1 p.m. due to increase in generation capacity.

On Monday, NGCP also declared yellow and red alerts on the Luzon grid after the forced outages of six power plants, which prompted the Department of Energy to ask the Energy Regulatory Commission (ERC) to investigate.

“The red and yellow alerts that occurred last Monday are under evaluation. We expect an updated report from our team next week. For this set of outages today, report will be submitted to the Commission in two weeks,” ERC Chairperson and Chief Executive Officer Monalisa C. Dimalanta said in a Viber message to BusinessWorld on Thursday.

Yellow alerts are issued when reserves fall below a designated safety margin. Red alerts are issued when the supply-demand balance deteriorates further, signaling the possibility of rotational brownouts.

Ms. Dimalanta noted that the ERC will issue a show cause order if warranted.

“Penalties are issued if explanation is not valid, but more importantly we see how causes can be addressed to avoid further outages,” she added. — Ashley Erika O. Jose