WHOLESALE Electricity Spot Market (WESM) prices in the Visayas and Mindanao shot up by 65 percent and 88 percent, respectively, last month. Rates are likely to remain elevated next month as long as the generating units remain offline and new supply is unavailable.
The WESM operator-Independent Electricity Market Operator of the Philippines (Iemop)-reported on Wednesday that electricity spot market in Visayas reached P18.59 per kilowatt hour (kWh) for the period July 26 to August 25. In Mindanao, WESM prices surged to P19.56 per kWh during the same period.
Iemop Vice President for Trading Operations Isidro Cacho Jr. said the WESM rates for Visayas and Mindanao are so far the highest ‘I have seen since I joined Iemop in 2006.’
Iemop said the supply margin of the Visayas and Mindanao declined by 190 megawatts (MW) and 253 MW, respectively, influenced by outage levels, supply constraints relative to demand, and grid alert conditions.
The tight supply situation owing to forced outages in the Visayas was compounded by constraints affecting the Luzon-Visayas High Voltage Direct Current (HVDC) interconnection.
The record highs are expected to persist for the period August 26 to September 25 still due to thin power margins. ‘Definitely, as long there is an advisory of yellow and red alerts then there is a very thin margin, particularly the Visayas, and that will result to higher prices in our electricity markets,’ Cacho said during a news briefing.
On Wednesday, Visayas was again placed on red and yellow alerts by the National Grid Corporation of the Philippines (NGCP).
The red alert takes effect from 1:00 p.m. to 10 p.m. while the yellow alert is from 10 p.m. to 11 p.m.
A red alert status is issued when power supply is insufficient to meet consumer demand and the transmission grid’s regulating requirement.
A yellow alert is issued when the operating margin is insufficient to meet the transmission grid’s contingency requirement.
Visayas’ available capacity stood at 2,124MW as against a peak demand of 2,555MW.
There are 11 plants on forced outage since the state of the month, four plants since August 2026, one plant since July, two plants since June, seven plants since May, three plants since 2025, two plants since 2024, two plants since 2023, and one plant since 2021, while 13 plants are running on derated capacities, for a total of 982.6MW unavailable to the grid.
The NGCP cited the unavailability of Visayas’ large coal plants TVI 1 and PEDC 3; outage of TVI 2 on Wednesday; and the limited power import from the Mindanao grid as the factors that contributed to the red alert.
In Mindanao, the yellow alert took effect from 1:00 p.m. to 9:00 p.m. Its available capacity was at 2,731MW while its peak demand reached 2,600MW.
There are 13 plants on forced outage in September, seven plants since August, four since July, one since June, two since January, one since 2025, and one since 2024, while six plants are running on derated capacities, for a total of 769.7MW unavailable to the grid.
The factors that contributed to the yellow alert declaration is the unavailability of Mindanao’s large coal plants GNPK 2 and 3.
The sustained high prices in Visayas and Mindanao also resulted in the application of the Secondary Price Cap (SPC)-a WESM price-mitigation mechanism designed to limit prolonged exposure to high spot market prices once the prescribed cumulative price threshold is reached.
In contrast, the average price in Luzon declined to P4.80 per kWh from P7.30 per kWh as demand decreased substantially and sufficient generation remained available despite several generating-unit outages and records a 632 MW increase in the supply margin.
At the system-wide level, average supply declined by 4.1 percent to 19,739 MW, while average demand fell by a larger 6.7 percent to 13,939 MW. As demand declined faster than supply, the average system-wide supply margin increased to 3,779 MW from 3,590 MW in July. Despite the relatively comfortable national supply margin, conditions differed significantly across the three grids.
‘August showed how regional conditions can differ significantly from the national supply picture. While Luzon maintained adequate supply margins, the Visayas experienced generation deficiencies due to forced outages, tighter supply margins, and transmission constraints that limited access to additional lower-cost power.
These conditions increased reliance on higher-cost oil-based plants and battery resources to meet demand, pushing market prices significantly higher,’ Iemop said.