Luzon grid placed under yellow alert on Tuesday, May 21, 2019

The Luzon grid was placed under yellow alert again on Tuesday amid thinning power reserves.

In an advisory, the National Grid Corp. of the Philippines (NGCP) said the alert stays in place from 10 a.m. to 12 noon and from 1 p.m. to 3 p.m.

Yellow alert refers to a condition in which the reserves are less than the capacity of the biggest plant online, which is 647 megawatts for Luzon.

The Luzon grid's available capacity is 11,933 MW against an expected peak demand of 11,163 MW.

A yellow alert, however, does not necessarily mean that power outages will ensue.

The NGCP said details on the cause will be announced by the Department of Energy (DOE) later in the day. —KBK, GMA News