Luzon was once again placed under a Yellow Alert on Saturday night, as several power plants went on unplanned outages and derated capacities, according to the National Grid Corporation of the Philippines (NGCP).

The Yellow Alert was implemented at 6PM, as the Luzon Grid had an operating requirement of 9,998 megawatts (MW) as against available capacity of 10,487MW.

Power generators that went offline includes CBK Power’s Kalayaan hydroelectric power plant in Laguna (720MW) and Unit 1 of Aboitiz Power Corporation’s GNPower Dinginin coal-fired power plant in Mariveles, Bataan (668MW).

Also down were Semirara Mining and Power Corporation’s Calaca Unit 2 (300MW) and SLPGC Units 2, 3, and 4 (200MW), and Unit 2 of ACEN’s South Luzon Thermal Energy Corporation (SLTEC) coal plant (123MW) – all in Calaca, Batangas.

As for those derated, or operated as lower capacities, both units of Team Energy’s Sual coal plant in Pangasinan were affected. Unit 1 operated at 220MW, or 380MW less than its 600MW capacity. Meanwhile, Unit 2 – also supposedly operating at 600MW – only operated at 570MW.

The Ilijan gas-fired plant in Batangas City operated at 817MW, or 383MW less than its supposed 1,200MW capacity. Ilijan experienced a series of deratings last year due to supply restrictions in the Malampaya gas field. SLTEC Unit 1, meanwhile, operated at 91MW, or 30MW lower than its 121MW capacity.

A total of 2,834 MW of power was shaved off the grid. 

Incidentally, the Philippines was participating in the annual Earth Hour during the Luzon Yellow Alert. During the Earth Hour, residents and establishments turn off their lights for one hour from 830 to 930PM with the goal of raising awareness on climate change and global warming. 

The Yellow Alert was lifted at 11 PM on Saturday due to “receding system demand.” 

Last week, the Independent Electricity Market Operator of the Philippines recorded the Luzon Grid’s highest peak demand for the year, so far, at 11,513 MW – close to last year’s actual peak demand of 11,601MW. 

Back in January, the Department of Energy – citing NGCP data – said that the week of the presidential elections may be sandwiched by Yellow and Red Alerts, specifically in Luzon if power plants go on unplanned outages like in the past three years. The statement was made following another Yellow Alert prior.