Electricity prices in the Wholesale Electricity Spot Market (WESM) climbed sharply in October as surging demand and unplanned power plant outages tightened supply across the grid.

Data from the Independent Electricity Market Operator of the Philippines (IEMOP) showed that the system-wide average price rose to P4.54 per kilowatt-hour (kWh) during the October billing period, up from P3.04 per kWh in September.

Average supply fell by around 823 megawatts (MW) to 19,889 MW, while demand edged higher to 13,881 MW—narrowing the supply margin and pushing market prices upward.

“The spot market price increased compared to the previous month. In September, demand was more tamed even without outages, so prices were lower. But every year, we see demand rise in October, and correspondingly, prices go up," IEMOP vice-president for trading operations Isidro Cacho Jr. said during a virtual briefing on Thursday.

“Distribution utilities that source from the spot market are seeing higher prices.”

Cacho noted that market conditions were further strained by Tropical Storms, recent earthquakes in Cebu and Davao, and forced outages of major generating units.

“Those events had an impact on the market because of multiple plant trippings and outages,” he said. “But these were immediately addressed—the regulator issued market suspensions that helped mitigate possible price spikes.”

Across the regions, Luzon prices increased to P3.96 per kWh from P2.57 per kWh in September, while Visayas climbed to P5.85 per kWh from P4.02 per kWh. In Mindanao, prices rose to P5.87 per kWh from P4.19 per kWh.

Coal remained the dominant fuel source, contributing 56.5 percent of total generation in October, followed by natural gas at 16 percent. Renewable energy—comprising hydro, geothermal, solar, wind, and biomass—accounted for a combined 27 percent of the mix.

Looking ahead, Cacho said prices may begin to ease as cooler weather and lower demand set in toward the year-end.

“Historically, October prices rise as economic activity picks up before Christmas, but from November to January, we usually see a downward trend,” he said. “Barring unplanned plant outages, we expect more stable and lower prices in the coming months.”