Visayas Grid Yellow Alerts Persist as Coal Outages Thin Reserves
Repeated Yellow Alerts in the Visayas trace to accumulated coal unit outages and constrained transmission, not a single failure, per NGCP. Emergency diesel dispatches have preserved service continuity, but they don't replace missing baseload capacity.
The National Grid Corporation of the Philippines placed the Visayas grid under a Yellow Alert from 5 to 9 p.m. on Sept. 27, 2026. The alert followed the early-morning shutdown of three large coal units, and NGCP has run similar alerts repeatedly since Sept. 22.
What the alert measures
A Yellow Alert isn't a blackout. NGCP raises it when capacity available to the grid falls short of the reserve margin needed to survive the sudden loss of one big unit. During an alert, the operator runs available units near their limits and holds back less flexibility than usual.
The recurring alerts mean the margin kept landing short. They don't mean the grid failed. NGCP says system voltage and frequency stayed within acceptable limits during the September alerts, though they came close to stress thresholds.
Where the missing megawatts come from
NGCP declared the first alert in this run on Sept. 22, 2026, from 4 p.m. to 8 p.m., with TVI 1, PEDC 3 and KSPC fully offline, a 36 MW derating at CEDC 3, and limited imports from Mindanao. The grid ran at 2,504 MW against a 2,419 MW peak that day, with 928.4 MW of capacity unavailable.
On Sept. 27, Panay Energy Development Corp Unit 3, KEPCO SPC Power Corp Unit 2 and Therma Visayas Inc. Unit 1 had been down since 4:34 a.m., per NGCP. Available capacity was 2,519 MW against a 2,342 MW peak, with 974.4 MW unavailable across 17 derated plants. That total is bigger than the roughly 928 MW figure from Sept. 22, so the shortfall varied day to day rather than settling at one number.
Transmission limits compound it. Several unit trips derated the Leyte grid, cutting how much power can be moved in, and Mindanao transfers stayed constrained. NGCP has blamed accumulated outages rather than any single failure for the alerts.
Recovery status and what's left open
Emergency diesel dispatches have kept service continuity closer than the reserve figures alone suggest, but they don't replace missing baseload capacity. The Department of Energy has ordered NGCP to install more than 250 MW of battery energy storage, and is weighing liquid fuel use as well. NGCP's plan had that storage commissioning in November 2026; whether it is energized on schedule remains unconfirmed.
NGCP hasn't given a return date for the flagged units at full rating, and its outlook has been that the grid may stay unstable until more generation comes online. For households and businesses, the exposure is rotating interruption risk at peak hours, not a confirmed outage.
More than 700 MWh of battery storage tenders on Indian grids are separate developments, not part of this fix. In the Visayas, the first real sign of relief would be a stretch of days with no Yellow Alert — and that hasn't happened yet. Whether the six named units come back at full rating, and whether the storage energizes in November, is still open.
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