By I. Inojales, Helen Castaño | 10:00 AM January 29, 2026
TAGBILARAN CITY — The country’s system-wide power supply improved in December 2025, but tighter operating conditions in the Visayas and Mindanao drove electricity prices higher in those regions, according to the Independent Electricity Market Operator of the Philippines (IEMOP).
In a press release issued Wednesday, January 28, IEMOP reported that average system-wide supply increased to 20,233 megawatts (MW) in December, up 1.2 percent from November. Electricity demand declined to 13,440 MW, or 0.5 percent lower month-on-month, widening the overall supply margin to 4,798 MW from 4,572 MW in the previous billing period.
Despite the improved national supply-demand balance, IEMOP said operating conditions varied across regions.
Supply margins in the Visayas and Mindanao declined by 136 MW and 245 MW, respectively, mainly due to planned and forced outages of generating plants. These tighter regional conditions, combined with transmission constraints that limited access to lower-cost power from Luzon, pushed the system-wide average energy price up to P4.38 per kilowatt-hour (kWh), from P3.98/kWh in November.
In Luzon, supply continued to increase while demand declined, similar to the previous month. These favorable conditions resulted in a lower average market price of P2.98/kWh, down from P3.52/kWh in November.
In contrast, the Visayas and Mindanao grids experienced tighter supply-demand balances. In the Visayas, available supply rose by 106 MW, but demand increased more sharply by 181 MW, leading to a net reduction in supply margin.
In Mindanao, supply fell by 245 MW alongside a 25 MW increase in demand, further tightening operating conditions.
IEMOP noted that the Visayas grid is typically supported by power imports from Luzon through the Leyte–Luzon high-voltage direct current (HVDC) interconnection. However, during December, the HVDC link either operated at its maximum Luzon-to-Visayas transfer limit of 250 MW or was offline for maintenance for 69 percent of the billing period—significantly higher than the 34 percent recorded in November. These prolonged limitations restricted the transfer of lower-cost Luzon generation and contributed to price separation between the Luzon and Visayas–Mindanao grids.
Simultaneous outages of several generating units in the Visayas and Mindanao during the first half of December further reduced baseload availability. In the Visayas, planned coal plant outages reached 238 MW, while forced outages across various technologies totaled 110 MW.
In Mindanao, unavailable capacity from coal and hydro units reached as high as 699 MW, in addition to 257 MW of forced outages from other generating technologies.
Under these tighter supply conditions, battery energy storage systems and other higher marginal-cost generators were dispatched more frequently during peak and constrained periods, driving regional market prices to between P7.86 and P8.53/kWh. In the Visayas, congestion along the 230-kilovolt Leyte–Cebu transmission corridor further limited internal power transfers, particularly affecting Leyte trading nodes, resulting in localized price separation and elevated nodal prices.
Both the Visayas and Mindanao also experienced reserve deficiencies. The Visayas recorded shortages in dispatchable reserves, while Mindanao faced deficits in both regulating and dispatchable reserves. These conditions led to higher reserve market clearing prices and contributed to overall price pressure in the affected regions.
Toward the final week of the December billing period, generation availability in the Visayas and Mindanao improved and key transmission constraints were eased. As operating conditions normalized, market prices in both regions declined to between P3.08/kWh and P3.21/kWh.
However, IEMOP said sustained high price conditions earlier in the month triggered the Secondary Price Cap for 213 intervals in the Visayas and 216 intervals in Mindanao. As a result, average electricity prices for December settled at P7.22/kWh in the Visayas and P7.82/kWh in Mindanao.
Spot market activity increased during the month, accounting for 13.2 percent of total traded volume, up from 12.3 percent in November. Correspondingly, the total spot market trading value rose to P14.19 billion from P13.13 billion.
In the reserve market, zonal prices generally declined, except for Regulation Up in Luzon, contingency and dispatchable reserves in the Visayas, and dispatchable reserves in Mindanao. Overall system-wide reserve market transactions decreased to P3.92 billion in December from P4.10 billion in November.
