El Niño risks mount for hydropower developers

By Sheldeen Joy Talavera, Reporter

HYDROPOWER DEVELOPERS are already feeling the effects of El Niño as prolonged dry spells lower reservoir levels, disrupting operations and critical maintenance activities.

Eric Y. Roxas, president of Repower Energy Development Corp. (REDC), said El Niño reduces the company’s hydropower plant efficiency to about 35% to 40%.

“During this period, the company takes advantage of the lower water volume to do our maintenance and repairs of our weirs, waterways infrastructure, dredging activities, and preventive maintenance activities,” Mr. Roxas told BusinessWorld.

In June, the Philippine Atmospheric, Geophysical and Astronomical Services Administration announced the onset of El Niño, which is widely expected to bring droughts to parts of the country. It is expected to escalate into a “Super El Niño” by late 2026 and persist until 2027.

Since hydropower facilities depend on reservoir and river levels, drier-than-normal conditions could prompt plants to run at partial capacity and reduce power generation output.

As of December 2025, hydropower accounted for about 12% of the country’s total installed power generation capacity, based on data from the Department of Energy.

This share remains vulnerable to weather-driven disruptions, particularly during El Niño, which is already affecting the operations of hydropower plants.

Mr. Roxas said REDC undertakes maintenance activities to ensure the company will take full advantage of increased water volume during the rainy season.

“The El Niño or dry season on the one hand becomes advantageous to us on the construction of our projects in development, with minimal delays due to weather,” he said.

REDC operates nine run-of-river hydropower plants across Luzon and Mindanao, totaling around 35 megawatts (MW), with six projects currently in development.

Dennis Michael P. Gonzales, senior vice-president of power producer First Gen Corp., said the impact of El Niño on the hydropower sector is “quite substantial,” as observed in one of their facilities.

He said the impact has reached a critical point for its Pantabangan hydropower facility in Nueva Ecija, with power generation output dropping from its original 120 MW to just 20 MW as of the end of July.

“Very close to completely shutting down the plant entirely,” Mr. Gonzales told BusinessWorld.

For context, he explained that every one-meter drop in the reservoir results in about a 3-MW decrease in power output.

“The low elevation reached this year is of huge concern as the reservoir is expected to recharge during the third quarter of the year,” Mr. Gonzales said.

“Failure to recharge sufficiently will lead to a low reservoir elevation for the next cropping season thus affecting the area that can be supported by irrigation as well as low power output due to low elevation as lower water volume releases.”

The Pantabangan hydroelectric plant is a multi-purpose hydro complex that also supplies irrigation water for the vast rice fields of Central Luzon.

While the plant saw higher-than-usual generation during the first half of the year, this was largely due to the previous year’s “generous inflows” being used to provide increased irrigation support for local farmlands. However, this heavy reliance on stored water has led to a “substantial drawdown” of the reservoir.

Unlike run-of-river plants where the impact of drought is instantaneous, large multi-purpose reservoirs like Pantabangan experience “a lag in impact,” Mr. Gonzales said.

“Even if the El Niño is encountered this year, the effect will be more felt next year,” he said.

The company official said the Luzon and Mindanao grids have significant hydropower capacity, accounting for 2,500 MW and 1,200 MW, respectively.

“Given its size, an El Niño phenomenon may trigger yellow alerts. In a way, we already felt this in June and July of this year when the hydropower plants experienced derating due to low water inflows,” Mr. Gonzales said.

A yellow alert is issued when the operating margin is insufficient to meet the transmission grid’s contingency requirement.

In Mindanao, state-run National Power Corp. (NPC) is working to complete the maintenance program for the Agus and Pulangi hydroelectric power plants to return to full operations by Aug. 20.

The Agus-Pulangi hydropower complex, which straddles the provinces of Lanao del Norte, Lanao del Sur and Bukidnon, is designed to generate 982 MW of electricity through seven run-of-river hydropower plants.

However, only about 700 MW of the facility’s capacity is currently operational due to aging infrastructure.

“Water has many competing uses, and with the possibility of a Super El Niño, energy requirements must always be balanced against water security and the needs of the communities,” NPC President and Chief Executive Officer Jericho Jonas B. Nograles said at a briefing last week.