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Mindanao’s power supply situation worsened Thursday afternoon, prompting the National Grid Corporation of the Philippines (NGCP) to raise a red alert for one hour as outages continued to strain generating reserves.
In its updated 1 p.m. bulletin, NGCP said the Mindanao grid would be under red alert from 5 p.m. to 6 p.m. Yellow alerts would cover the periods from 1 p.m. to 5 p.m. and 6 p.m. to 9 p.m.
The new schedule marked an escalation from NGCP’s earlier advisory, which placed Mindanao under yellow alert from 1 p.m. to 4 p.m. and from 5 p.m. to 7 p.m.
Earlier Thursday, NGCP projected available capacity in Mindanao at 2,724 megawatts against peak demand of 2,552 MW. Despite capacity exceeding projected demand, reserves were insufficient to satisfy the grid’s required contingency margin.
The earlier alert was linked partly to the unavailability of Units 2 and 3 of GNPower Kauswagan. Six generating plants had gone on forced outage this month, while six others were operating below their rated capacities. NGCP placed unavailable capacity at about 671.1 MW.
The Visayas grid was separately scheduled to remain under red alert from 2 p.m. to 9 p.m., with yellow alerts from 1 p.m. to 2 p.m. and 9 p.m. to 10 p.m. Its available capacity was projected at 2,205 MW against demand of 2,460 MW.
Supply constraints in the Visayas were attributed partly to the unavailability of both units of Therma Visayas and Unit 3 of Panay Energy Development Corp., along with reduced electricity imports from Mindanao. About 979.9 MW of generating capacity was unavailable in the Visayas earlier Thursday.
Under NGCP classifications, a yellow alert indicates that operating reserves are below the contingency requirement. A red alert is declared when available supply can no longer sufficiently cover consumer demand and the transmission system’s regulating requirement.