TACLOBAN CITY — The Visayas grid has been placed under yellow, and at times red, alert for the past two weeks as available power supply barely meets peak consumer demand.

While a yellow alert does not automatically result in power interruptions, unstable electricity supply increases operational risks, raises business costs, and weakens investor confidence in the country’s ability to maintain a reliable power system.

The Institute for Climate and Sustainable Cities (ICSC) said the repeated red and yellow alerts highlight how outages involving several large centralized coal plants can quickly strain the Philippine power system and lead to outages across interconnected grids.

In its yellow alert advisory for the Visayas grid on Tuesday, the National Grid Corporation of the Philippines (NGCP) reported an available capacity of 2,670 megawatts (MW), while projected peak demand from 4 p.m. to 8 p.m. reached 2,479 MW.

According to NGCP, 10 power plants have been on forced outage since May 2026, one since March 2026, three since 2025, two since 2024, two since 2023, and one since 2021. In addition, 14 plants are operating at reduced capacities, leaving a total of 867 MW unavailable to the grid.

The ICSC said the continuing outages of three major coal plants in the Visayas triggered the yellow alert declaration. These include the Toledo-based Therma Visayas Inc. (TVI) Units 1 and 2 with a combined capacity of 300 MW, and the 150-MW Panay Energy Development Corporation (PEDC) Unit 3 in Iloilo City.

Under NGCP’s Grid Operating and Maintenance Plan (GOMP), no baseload power plant should be on outage from April to June, when electricity demand usually peaks.

However, the ICSC noted that these plants were not only unavailable during the second quarter of 2026, but had also exceeded the Energy Regulatory Commission’s annual outage allowance for baseload facilities.

According to the group, TVI Unit 1 has accumulated 90 outage days and has been offline since 3 May, while TVI Unit 2 has recorded 91 outage days and has been offline since 24 March. PEDC Unit 3, meanwhile, has accumulated 43 outage days and has been offline since 6 May.

“These coal power plants account for 52.8 percent of the unavailable capacity in the Visayas grid, further underscoring how dependence on a small number of large centralized baseload facilities can quickly strain system reliability,” the ICSC said.

The think tank warned that unless the affected plants return online, the capacity deficit and recurring yellow alerts in the Visayas grid are likely to continue.

“This shows how centralized coal plants impact the grid — that a single outage of these facilities can significantly strain the grid, leading to tight power supply situations,” it added.

Amid the unstable power supply, two municipalities in Samar have become examples of localized energy resilience through the use of rooftop solar systems.

The municipalities of Guiuan and Paranas installed rooftop solar photovoltaic systems in their municipal halls, allowing them to continue providing essential services such as phone charging and communications during power interruptions.

The ICSC said the projects demonstrate how localized energy systems can continue powering essential services even when major transmission lines or large power plants are offline.

The group is now urging both consumers and government institutions to accelerate the adoption of rooftop solar and net-metering systems to strengthen local energy resilience and reduce dependence on centralized power infrastructure.

While rooftop solar systems are not direct replacements for large baseload plants, the ICSC said wider adoption can help reduce peak daytime demand, improve local resilience, and lessen pressure on the grid during supply shortages.