Luzon grid on yellow alert

MANILA, Philippines - The Luzon grid was placed on yellow alert yesterday after two power plants tripped, causing power reserves to fall below required levels.

The National Grid Corp. of the Philippines (NGCP) said the yellow alert from 10 a.m. to 11 a.m. and from 1 p.m. to 3 p.m. was “due to insufficient ancillary services (AS) capacity.” The alert status was lifted at around 2 p.m.

A yellow alert means power reserves are below the minimum level set by the regulator, but it does not necessarily result in rotational brownouts.

The NGCP said AS support the transmission of capacity and energy from resources to loads while maintaining reliable operation of the transmission system in accordance with good utility practice and grid code.

NGCP said supply was estimated at 9,508 megawatts compared to a peak demand of 8,911 MW.

In a text message, Department of Energy spokesman Felix William Fuentebella said the yellow alert was due to the forced outage of Unit 1 of the Sual power plant and Unit 3 of the Kalayaan power plant.

Unit 2 of the Sual power plant, Units 1 and 2 of Malaya, Unit 2 of Calaca, Module 20 of the Sta. Rita module, Units 1, 3 and 4 of Limay and Unit 2 of the Angat hydropower plant also went offline, according to the Manila Electric Co. (Meralco).

Unit 1 of the Calaca coal-fired power plant had limited output from 200 MW to 147 MW, Meralco added.