ICSC Highlights Urgent Need for Resilient Distributed Power System After Luzon and Visayas Grid Alerts

Yellow alerts raised across the Luzon and Visayas grids on April 16 have once again underscored structural vulnerabilities in the Philippines’ power system, particularly its heavy reliance on large baseload power plants.

The Institute for Climate and Sustainable Cities (ICSC) reiterated that the country’s energy framework remains largely baseload-centric, making it susceptible to disruptions when major facilities experience outages or operate below optimal capacity. According to the group, even short-term interruptions can significantly reduce available reserves and destabilize grid operations.

Data from the National Grid Corporation of the Philippines (NGCP) showed that unplanned outages and derations resulted in the loss of approximately 5,137 MW of baseload capacity in the Luzon grid during the incident.

Among the key disruptions were simultaneous unplanned outages at the Excellent Energy Resources, Inc. (EERI) 1, 2, and 3 plants, which have a combined capacity of 1,262 MW, and the Ilijan Block A and B plants, with a combined capacity of 1,200 MW. Both facilities are liquefied natural gas (LNG)-fired and utilize the same LNG terminal, highlighting a concentration risk within the system. Although the outages lasted only a few hours and were later resolved, they exposed the fragility of relying on clustered, large-scale generation assets.

Further compounding the situation were derated operations at major coal-fired units, including Sual 1 and Sual 2. At the time of the alert, Sual 1 was generating only 235 MW out of its 647 MW capacity, while Sual 2 was producing 300 MW—both operating at less than half of their dependable output.

While the unavailability of the Magat 1, 2, 3, and 4 hydropower units, totaling 345 MW, was also cited, these outages were part of scheduled maintenance under NGCP’s Grid Operating and Maintenance Program (GOMP), distinguishing them from the unplanned disruptions that triggered the alerts.

The situation also had cascading effects on the Visayas grid, which relies heavily on high-voltage direct current (HVDC) imports from Luzon and Mindanao. As Luzon’s reserves tightened, the Visayas grid—already operating on negative reserves—experienced supply strain, resulting in a yellow alert.

ICSC noted that such scenarios were anticipated in its Philippine Power Outlook Report, which warned that unplanned outages beyond the Department of Energy’s approved schedules could significantly worsen supply conditions. The events of April 16 reflected this risk, as unexpected outages from LNG facilities further constrained available capacity.

The incident also highlighted that a substantial portion of unavailable capacity during the alert stemmed from LNG-fired plants, rather than scheduled hydropower maintenance alone. This reinforces concerns about the system’s dependence on a limited number of large generating units and the need for more balanced capacity planning.

Energy experts emphasized that addressing recurring grid alerts will require a shift toward a more decentralized, diversified, and flexible energy system. Increasing the share of indigenous renewable energy sources—such as geothermal, hydropower, solar, and wind—alongside energy storage systems, is seen as critical to enhancing resilience and reducing exposure to global fuel price volatility.

Given the Philippines’ archipelagic geography and vulnerability to extreme weather events, a more geographically distributed power generation model is also being advocated. Such an approach would reduce reliance on centralized plants and improve local energy security.

Moreover, stakeholders highlighted that future grid reliability will depend on flexibility-driven solutions, including advanced energy storage technologies, modern grid management systems, and fast-ramping generation capacity, rather than solely expanding traditional baseload infrastructure.

As the country continues to face recurring grid constraints, experts stress that transitioning to a diversified and resilient energy system will be key to ensuring stable, reliable, and affordable electricity supply nationwide.