MANILA, June 2 -- The Visayas grid was placed under yellow alert anew on Tuesday as several major coal-fired power plant units remained unavailable, tightening power reserves amid rising electricity demand.

In an advisory, the National Grid Corporation of the Philippines (NGCP) said the yellow alert would be in effect from 3 p.m. to 9 p.m.

The grid's available capacity stood at 2,542 megawatts (MW), while peak demand was projected to reach 2,412 MW, leaving a thin reserve margin that falls short of contingency requirements.

The alert comes as four generating units from key coal-fired power plants remain on forced outage: Units 1 and 2 of Therma Visayas Inc. (TVI), Unit 3 of Panay Energy Development Corporation (PEDC), and Unit 2 of KE...