It is also seeking the accountability of the National Grid Corporation of the Philippines (NGCP).
In its statement on Friday, May 15, the Department of Energy (DOE) said it has directed the Grid Reliability Task Force (GRTF) to conduct a full investigation into the tripping of the 500-kilovolt (kV) Tayabas–Ilijan and Ilijan–Dasmariñas transmission lines last May 13.
Both serve as the main power transmission lines and is where a large amount of energy flows—about about 12% of the supply in Luzon—from the plants to Metro Manila and other parts of Luzon, as well as to the Visayas through the interconnected system.
Within minutes of the transmission line tripping, Ilijan Blocks A and B and Excellent Energy Resources Inc. (EERI) Units 1, 2, and 3 were disconnected from the Luzon grid, the energy department stated.
Specifically disconnected were the two large LNGPH plants: the 1,262.1 MW Excellent Energy Resources, Inc. (EERI) and the 1,200 MW South Premiere Power Corporation Ilijan Natural Gas-fired Power Plant.
The said incident disconnected a total of 2,462.1 megawatts (MW) of natural gas capacity from the Luzon grid, which triggered widespread power interruptions across Luzon.
Major disruptions involving these facilities can therefore have broader implications on grid operations, power flows, and supply conditions in both Luzon and Visayas.
In addition, this also prevented power transfer from Luzon to Visayas, with conditions of the Luzon system aggravated when Masinloc Unit 3, with a capacity of 325 MW, went on forced outage.
The Ilijan power complex and related facilities play a critical role in maintaining system reliability and supply adequacy in Luzon because of the significant generation capacity connected through these transmission corridors, noted the DOE.
Due to this, the alert levels were raised. Yellow meant the reserve supply is low but still sufficient to meet the demand under normal conditions, while Red notes that the reserve or supply of electricity is not sufficient for the current demand or the loading of the transmission lines is critical.
In light of the situation, it earlier requested full incident disclosure from the National Grid Corporation of the Philippines (NGCP), including complete operational data, incident reports, and technical findings necessary to find the root cause of the disturbance.
“Two major 500-kV transmission arteries feeding power into Metro Manila and the broader Luzon grid were suddenly cut off. These lines carried roughly 12 percent of Luzon’s supply at the time,” noted energy chief Sharon Garin. “An incident of this scale demands full technical disclosure, clear accountability, and immediate corrective action,.”
To determine the circumstances surrounding the incident, the DOE is convening the GRTF which js composed of the DOE, the Energy Regulatory Commission (ERC), the Independent Electricity Market Operator of the Philippines (IEMOP), the National Transmission Corporation (TransCo), and the Power Sector Assets and Liabilities Management Corporation (PSALM).
Together, they will conduct a comprehensive technical assessment.
“The public deserves a complete accounting of incidents of this magnitude. We will ensure that all operational, technical, and compliance dimensions are fully examined and that appropriate actions are taken where warranted,” Garin added.
NGCP DIRECTED TO SUBMIT COMPREHENSIVE INCIDENT REPORT
Prior to the GRTF’s convening, the DOE and ERC have jointly directed the National Grid Corporation of the Philippines (NGCP) to submit a comprehensive incident report on the yellow and red alert declarations that affected the Luzon and Visayas grids from May 12 to 14.
The government agencies are demanding a full accounting of the supply disruptions that placed millions of Filipino consumers at risk over a three-day period.
“The DOE is focused on ensuring stable power supply, protecting consumers, and enforcing accountability across the power sector,” Garin said. “The public deserves a full and transparent accounting of the incidents that led to these grid alerts, and we are requiring NGCP to comply fully with all reportorial and regulatory obligations.”
The Department of Energy’s technical teams have been actively and independently verifying the status of all affected generating units and transmission facilities, and to assess whether NGCP and concerned generation companies complied with dispatch instructions and restoration timelines during the alert period.
Among the key information NGCP is required to report, as per the energy department, are the specific date, time, duration, and areas affected by each alert declaration; the root cause or triggering factor of each supply deficiency or grid contingency; and all generating units, transmission lines, and facilities that experienced forced outages, deratings, or reduced availability.
It will also look into the reserve and demand levels at the time of each alert; immediate corrective and load management measures undertaken; the restoration timeline and normalization actions; and all related coordination with the DOE, ERC, and concerned generation companies.
Under ERC Resolution No. 13, Series of 2010, NGCP is separately obligated to submit an Initial Report within sixty (60) minutes from the time of any system disruption. Compliance with this reportorial requirement is being closely monitored by both the DOE and the ERC.
ENERGY CONSERVATION
Amid the current supply conditions in Luzon and Visayas, Secretary Garin also appealed to the public to practice energy conservation, particularly during peak demand hours, to help prevent further strain on the grid.
“While the government and the energy sector continue working to stabilize supply conditions, we appeal to the public to use electricity responsibly, especially during peak hours. Simple conservation measures can help reduce pressure on the system and support overall grid reliability during this critical period,” Secretary Garin said.
In line with that, DOE has also issued an Advisory directing all Energy Efficiency and Conservation (EEC) Professionals of Government Entities to strictly implement and intensify energy efficiency and conservation measures across all public offices, buildings, and facilities—effective immediately.
Likewise, government entities have also been directed to reduce non-essential electricity use, optimize building systems, and ensure full compliance with mandated energy efficiency standards, particularly during peak demand hours.
Garin emphasized that the public sector carries both the “obligation and the capacity” to make an immediate, measurable contribution to grid stability.
The DOE encourages industries and households to practice simple and small energy conservation habits.
Air conditioning units should be set at 24–25°C and no lower, noting that is the single largest electricity load in most homes and commercial spaces, and every degree of upward adjustment reduces consumption meaningfully.
Me awhile, heavy appliances such as washing machines and electric water heaters should be shifted to early morning or late evening, outside of peak demand periods.
Lights, electric fans, and all appliances not in active use should be switched off.
Commercial establishments and building administrators are also requested to set centralized air conditioning systems within the 24–25°C recommended range, stagger the operation of high-load equipment during peak periods, and ensure all non-essential lighting and appliances are powered down outside business hours in the same memorandum.
The Department has also called on concerned distribution utilities to activate their Interruptible Load Program to help stabilize supply conditions.