Luzon grid on yellow alert

A yellow alert was raised on the Luzon grid yesterday after a major power plant tripped, causing power reserves to drop below the minimum requirement.

The National Grid Corp. of the Philippines (NGCP) said the Luzon grid was on yellow alert from 10 a.m. to 4 p.m. “due to lower level operating reserves brought about by insufficient power supply.”

A yellow alert means power reserves are below the minimum level set by the regulator, which is equivalent to the capacity of the largest running power plant in the grid.

NGCP estimated supply to be at 9,717 megawatts (MW) as compared to a peak demand of 9,246 MW. This means power reserves were projected at 471 MW.

Manila Electric Co. (Meralco) said power supply dropped after the emergency shutdown of Unit 2 of the Sual power plant in Pangasinan, which has a capacity of 647 MW.

Also, the Unit 1 of the Calaca coal-fired power plant has limited output from 200 MW to 180 MW.

The limited power supply also happened as several power plants are on maintenance shutdown namely the 300-MW Unit 2 of the Calaca power plant, the 262-MW Sta. Rita Mod. 20 plant, the 135MW South Luzon Thermal Corp. plant, the 60-MW Unit 2 of Limay power plant and the 50-MW Unit 2 of Angat hydroelectric power facility, Meralco said.

Meralco also urged customers to be energy efficient to help avoid manual load dropping (MLD) or rotational brownout.

Several instances of yellow alert during the June supply month pushed electricity rates higher in July. For the month of June, Meralco said there were five instances of yellow alerts in (June 13, 14, 17, 21, and 22) as several power plants went on scheduled and unscheduled outage.