Power supply alerts could persist in the coming months as rising temperatures and the looming onset of the El Niño phenomenon continue to drive electricity demand higher, Department of Energy (DOE) projections indicate.
Energy Undersecretary Felix William Fuentebella said in an online news conference that the Visayas grid is expected to experience multiple alert conditions in the coming months.
These include seven yellow alerts during afternoon peak hours, as well as six red alerts and seven yellow alerts during evening peak periods.
In Mindanao, the DOE projects no red alerts but six yellow alerts from September to November and one more yellow alert for Luzon.
The Philippines remains under El Niño southern oscillation (Enso)-neutral conditions, but state the weather bureau had warned of a high probability-around 70 to 79 percent-that El Niño may develop between June and August this year and could persist into early 2027. The phenomenon is expected to significantly affect weather patterns, water supply, and electricity demand.
This warning comes as the Visayas grid continues to grapple with major plant outages and tight operating reserves, raising concerns over possible rotational brownouts should additional generating units go offline.
Speaking during the MyTV Cebu OPENLINE News Forum on Tuesday, Neil Martin Modina, assistant vice president and head of Visayas System Operations of the National Grid Corporation of the Philippines (NGCP), said the transmission operator is closely monitoring grid conditions amid rising demand and limited supply.
‘Yellow alert means our operating margin cannot meet the contingency reserve, while a red alert means the operating margin can no longer sustain the regulating reserve of the transmission network,’ Modina explained.
He noted that as of Monday evening, the Visayas grid remained under yellow alert, with an operating margin of only 57 megawatts (MW). ‘Kung red alert na, dili na maka-sustain sa regulating reserve. Mao nang possible ang rotational brownouts [If it reaches red alert status, the grid can no longer sustain the regulating reserve. That is why rotational brownouts may occur],’ he added.
NGCP also reported that several major generating units in the Visayas remain offline, significantly affecting supply. These include two 169-megawatt units of Therma Visayas Inc. (TVI) in Cebu and the 150-megawatt Panay Energy Development Corp. (PEDC) plant in Panay, contributing to a total unavailable capacity of 845 megawatts.
‘Dako na kaayo na [That’s already a large amount],’ Modina said, underscoring the scale of the outages.
Power demand in Cebu alone reached 1,128 megawatts on May 18-nearly half of the Visayas grid’s total demand of 2,600 megawatts.
‘Cebu consumes almost half of the Visayas demand. Kinahanglan gyud og additional generation diri sa Cebu [We really need additional power generation here in Cebu],’ he added.
NGCP said the situation could improve once the affected plants resume operations. Based on projections, TVI Unit 2 is expected to return by August 22, while Unit 1 may resume operations by August 30. The 150-megawatt Panay plant is projected to come back online by July 7.
‘If the Panay plant returns as scheduled, adding 150 megawatts to the current 57-megawatt operating margin would bring reserves to over 200 megawatts. Safe na siya nga operating margin,’ Modina said.
Despite the tight supply, NGCP said interconnection with the Mindanao grid-completed in 2024-has helped stabilize the Visayas system during critical periods. Mindanao currently has an estimated 450-megawatt surplus that can be exported to the Visayas when needed.
On Monday night, Luzon also supplied 176 megawatts to the Visayas grid, with the Luzon system capable of delivering up to 250 megawatts, according to NGCP.
‘No brownout yesterday because of the available support from interconnected grids,’ Modina said.
However, NGCP warned that the grid remains vulnerable to forced outages and derated power plants, particularly during summer months when demand spikes due to extreme heat.
‘Demand always increases during summer because of higher temperatures,’ Modina said.
Under DOE policy, power plants are generally prohibited from conducting maintenance shutdowns during peak summer months. Scheduled maintenance is typically allowed only during the first, third, and fourth quarters of the year.
‘If they deviate from the approved schedule, that becomes a forced outage, and that creates imbalance in the grid,’ he said.
NGCP added that it continues real-time monitoring of generating plants and coordinates closely with operators whenever technical issues arise. The current outage at TVI was reportedly caused by a bearing problem.
Should red alerts occur, NGCP said rotational brownouts would be implemented proportionately among distribution utilities based on their share of demand.
For example, Visayan Electric Company, which accounts for around 27 percent of demand, would be directed to implement outages equivalent to its load share to prevent a cascading grid failure.
‘Kung dili ma-implement ang scheduled load dropping, possible mag-cascading effect sa entire grid [If scheduled load dropping is not implemented, it could cause a cascading effect across the entire grid],’ Modina warned.
As of May 19, NGCP placed the Visayas grid under yellow alert from 3:00 p.m. To 9:00 p.m., citing tight power reserves. Available capacity stood at 2,691 megawatts, while demand reached 2,594 megawatts, leaving a slim operating margin of 97 megawatts.
Meanwhile, Modina said additional generation projects are in the pipeline for the Visayas, including a proposed waste-to-energy facility in Bacolod City that has already been endorsed by the DOE.
DOE data shows 37 committed power projects in the Visayas, most of them renewable energy-based.
These include two coal-fired plants: the expansion project of TVI in Toledo City, Cebu, and the Palm Concepcion Coal-Fired Power Plant Unit II in Iloilo. Combined, these projects will add at least 300 megawatts of capacity.
TVI’s expansion is expected to begin testing and commissioning in October this year, with full operations targeted for August 2028.
Other committed projects in the Visayas include 14 solar plants, three diesel plants, one geothermal plant, nine wind farms, four hydroelectric projects, and four biomass facilities.
In addition, 15 Battery Energy Storage System (BESS) projects are currently in the pipeline for the Visayas grid.