House leaders are pushing for a congressional investigation into the massive power disruption that triggered red and yellow alerts in the Luzon and Visayas grids earlier this month, amid growing concerns over the reliability of the country’s transmission system.
House Resolution No. 1024 seeks an inquiry into the May 13 tripping of the 500-kilovolt Tayabas-Ilijan and Dasmariñas-Ilijan transmission lines operated by the National Grid Corporation of the Philippines (NGCP).
The twin transmission failures disconnected more than 2,462 megawatts of power from the grid and forced NGCP to implement manual load dropping across several areas.
Around 3.9 million customers in Metro Manila, Batangas, Bulacan, Cavite, Laguna, and Rizal were affected by the outages.
Lawmakers said the incident exposed serious vulnerabilities in the country’s transmission backbone and raised questions about grid reliability, maintenance, and compliance with operational standards.
“The back-to-back tripping of these major transmission lines exposed serious weaknesses in the reliability and resilience of our power grid,” the resolution stated.
The proposed measure will examine whether the incident was caused by force majeure or by possible failures in maintenance, investment, and system protection measures.
The resolution also cited concerns over NGCP’s alleged failure to promptly report the incident to the Department of Energy (DOE) and the Energy Regulatory Commission (ERC), despite requirements under the Philippine Grid Code.
Lawmakers noted that NGCP is required to submit an initial report within 60 minutes of major system disruptions.
“It is a serious concern that NGCP failed to promptly declare and report the Tayabas-Ilijan-Dasmariñas line trip to the relevant regulatory authorities at the time of the incident,” the resolution said.
The inquiry will also focus on the status of the Transmission Development Plan, the company’s compliance with contingency standards, and whether repeated technical failures and alleged reporting lapses may constitute violations of NGCP’s legislative franchise.
House leaders stressed that the investigation is aimed not only at determining accountability but also at strengthening energy security and protecting consumers from recurring large-scale outages.
“The Filipino people deserve a power system that is stable, reliable, and prepared for contingencies,” the resolution stated.