MANILA, Nov. 19 -- The National Grid Corporation of the Philippines (NGCP) has placed the Visayas grid on yellow alert from 3 p.m. to 8 p.m. on Wednesday due to insufficient operating margin as several power plants are unavailable or at derated capacities.

In an advisory, the power transmission operator said the grid has available capacity of 2,694 megawatts (MW) while peak demand is around 2,351 MW.

A yellow alert is issued when the margin between the capacity and expected peak demand is small.

It cited as major factors in the issuance of the yellow alert during the day the unavailability of Therma Visayas Inc.'s (TVI) coal-fired power plant units 1 and 2, which has a capacity of 169MW each, and the emergency shutdown of the Leyte Geo...