Energy Undersecretary Mario Marasigan told an online press conference on Aug. 3 that Kepco Salcon Power Corp. unit 1, Cebu Energy Development Corp. (CEDC) unit 1, and one unit of the Toledo Power Corp. (TPC) went on forced outage .
He said the assessment of TPC was still ongoing after the plant went offline last Saturday, but it was expected to resume operations by Aug. 6.
CEDC Unit 1, meanwhile, was forced to shut down ahead of its scheduled preventive maintenance, prompting the operator to begin the maintenance work earlier than planned.
Marasigan added that two generating units of Thermal Visayas Inc. (TVI) have remained offline since May due to thermal issues affecting their main turbines. Both units are expected to return to service by the end of August.
“So, this only shows the vulnerability of our Visayas grid,” said Marasigan.
Yellow alerts
A yellow alert was issued from 5 p.m. to 9 p.m. on Aug. 3 after the unavailability of three power plants reduced available generating capacity to 2,464 MW, leaving the Visayas grid with an operating reserve of only 200 MW against a peak demand of 2,262 MW.
Since 2021, 19 power plants have gone on forced outage, while 16 others have been operating at derated capacities—a reduction in the maximum electricity a plant can safely generate due to equipment issues, maintenance, high ambient temperatures, or other operational limitations.
According to National Grid Corporation of the Philippines (NGCP), these forced outages and derated operations have taken a combined 1,055.8 megawatts (MW) of generating capacity out of the Visayas grid.
Mindanao too?
Marasigan said that while the Luzon grid remains stable, the Mindanao grid could face yellow alerts as rising power demand coincides with the scheduled preventive maintenance of several power plants.
He added that the situation could further strain the Mindanao grid because its capacity to supply electricity to the Visayas through the interconnection has also been reduced.
The Visayas grid imports as much as 450 MW from Mindanao through the Mindanao–Visayas Interconnection Project (MVIP).
With the Mindanao grid also facing tighter supply conditions, Marasigan said additional reserve capacity must be secured to help address the recurring yellow and red alerts, as well as manual load dropping incidents, in the Visayas.
He said NGCP has been advised to directly negotiate and enter into Ancillary Services Procurement Agreements (ASPAs) to secure additional reserve power for the Visayas grid.
Temporary relief
An ASPA is a contract between the transmission operator and a power generator or other qualified service provider for the supply of ancillary services, or reserve power, needed to maintain the stability and reliability of the power grid.
Marasigan said the DOE has identified about 270 MW of battery energy storage system (BESS) capacity that can be deployed in the Visayas. Of this, at least 50 MW is already undergoing testing and commissioning.
He added that Aboitiz Power Corp. also has two power barges with a combined generating capacity of 50 MW in Navotas that are ready to be transferred to Cebu to help augment the region's power supply.
“So that clearly shows that we need to address the reliability needs of power supply in the Visayas. And this can only be done in this emergency situation through directly negotiated ancillary service provision,” he added.
Marasigan said the directives had already been coordinated with the concerned power proponents and NGCP to immediately proceed with the direct negotiation and execution of ASPAs in the Visayas. —Ed: Corrie S. Narisma
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