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Manila Bulletin devider Business devider Trade & Industry devider WESM prices surge in August due to unplanned plant outages

WESM prices surge in August due to unplanned plant outages

Published Sep 3, 2025 11:37 am  |  Updated Sep 3, 2025 02:39 pm
Unplanned and scheduled power plant shutdowns caused a significant spike in prices on the Wholesale Electricity Spot Market (WESM) in August, according to the Independent Electricity Market Operator of the Philippines (IEMOP).
In a briefing on Wednesday, Sept. 3, IEMOP reported that the average WESM price surged by 15 percent, from ₱3.99 per kilowatt-hour (kWh) in July to ₱4.59/kWh in August, which will be passed on to consumers through the generation charge on their electricity bills.
The overall average system demand also grew from 13,812 megawatts (MW) to 14,052 MW.
Among the three main regions, Mindanao experienced the steepest price hike, with prices jumping 75 percent from ₱3.80/kWh to ₱6.66/kWh. This was driven by a drop in supply, from 3,685 MW to 3,561 MW, due to coal plant outages.
These outages triggered a yellow alert on Aug. 1, a warning issued by the National Grid Corporation of the Philippines (NGCP) when the power grid's operating margin is not sufficient to meet contingency requirements.
In the Visayas, spot market prices also climbed significantly, rising 45.7% from ₱4.39/kWh to ₱6.40/kWh. This was caused by outages at several coal plants and the shutdown of biomass facilities at the end of the milling season, which led to yellow alerts in early August. IEMOP’s Vice President for Trading Operations, Isidro E. Cacho Jr., noted that Luzon was able to export power to help with the supply shortage.
“Because of the impact of forced outages, Visayas' local supply thinned. This is why there were imports from Luzon,” Cacho said. “Unfortunately, Mindanao also experienced both forced and planned outages, which lessened the supply there.”
In contrast, Luzon saw its prices decrease slightly from ₱3.92/kWh to ₱3.76/kWh. Despite a small increase in demand to 9,882 MW, Luzon’s supply also saw an uptick to 14,646 MW.
“In the Luzon market, there was ample supply that it was able to export to Visayas. The demand was up, but only a little,” Cacho explained. “In Luzon, I would say it's stable compared to the previous months.”
Cacho also pointed out that prices can be affected by weather patterns, especially during the rainy season. He added that the start of the “BER” months (September, October, November, December) could lead to higher market movements due to increased demand as manufacturing plants prepare for the Christmas season.
In terms of power generation, IEMOP reported that renewable energy (RE) contributed 26 percent of the total system-wide generation, while natural gas increased to 22 percent. The share of coal dropped from 54.1 percent to 50.6 percent, and geothermal decreased slightly from 8.1 percent to 7.8 percent.

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Wholesale Electricity Spot Market (WESM) Independent Electricity Market Operator of the Philippines (IEMOP)
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