Contingency reserve for Visayas grid a ‘challenge’ – IEMOP

By Rjay Zuriaga Castor

The Independent Electricity Market Operator of the Philippines (IEMOP) has acknowledged ongoing difficulties in ensuring a safety net for the Visayas grid to maintain consistent functionality during a sudden tripping of a generating unit or loss of a transmission line.

Isidro Cacho Jr., Head of the Trading Operations Department of IEMOP, said establishing a contingency reserve specifically for the Visayas region remains a significant challenge.

“The provision of reserves has shown remarkable improvement in 2024, with increased capacity scheduled for regulation, contingency, and dispatchable reserves across all regions, thereby meeting the required level of frequency-controlled ancillary services or operating reserves in the different regions,” he said during the Philippine Electric Power Industry Forum in Iloilo City last week.

“However, for Visayas, the provision of contingency reserves to meet the grid code requirements remains a challenge,” Cacho stressed.

For clarity, reserves or ancillary services are services needed to maintain balance in the power system to ensure normal frequency and voltage levels in response to demand changes, variability of renewable energy, and possible loss of a large generating unit.

Operating reserves involve regulation, contingency, and dispatchable reserves.

Regulation reserves balance power generation and consumption dynamically; contingency reserves act promptly during sudden generator outages to ensure consistent grid functionality; while a dispatchable reserve steps in as the subsequent line of action during grid challenges.

The “stand-by” capacities, according to Cacho, are scheduled by the National Grid Corporation of the Philippines (NGCP), which acts as the System Operator, to ensure a stable and reliable operation of the grid. Generators are the primary providers of the reserves.

For Panay, major reserve providers are coal-fired power plants in Iloilo: Panay Energy Development Corp. (PEDC) 1 providing 83.7 megawatts (MW), PEDC 2 with 83.7 MW, PEDC 3 with 150 MW, and Palm Concepcion Power Corporation with 135 MW.

According to January 2024 data from IEMOP, the Visayas region has achieved a completion rate of 94 percent for its reserves, which is slightly lower compared to Luzon’s 100 percent and Mindanao’s 97 percent completion rates.

The Visayas region is expected to have 168 MW of regulation reserve, 174 MW for contingency, and 350 MW for dispatchable reserve. The completion rate for contingency reserves in the Visayas stands at 89 percent, with 154 MW registered to its capacity so far.

Cacho said in a March briefing that the Visayas grid could experience yellow alerts this summer, especially in incidents where there are forced outages in big power plants.

“From what we are seeing, if we look at the different grids in Mindanao, they definitely have no more issues with [power] supply and are now looking only at Luzon and the Visayas. What I think in our simulation, what we saw is that if there are unplanned and forced outages that are big, that will contribute to the possibility of a yellow alert for summer,” the IEMOP official said.

A yellow alert, issued by the NGCP, means the reserve level in the grid has gone below the required contingency reserve.

If the Visayas grid will not be able to complete the registration of its reserves, unexpected changes in the demand and supply of electricity, hence the recurrence of the days-long power outage that hit Panay Island in March 2023 and early January this year.

On the part of the Department of Energy (DOE), Undersecretary Rowena Cristina Guevara said they are in constant talks with the energy stakeholders from the industry and government for short-term and long-term solutions to prevent the recurrence of the massive blackout in Panay Island.

“The solutions offered range from providing contingency reserve from the headroom of generators in Panay Island,” she said.

Guevarra said they are also looking at the provision of black start service, reactive power support in the Panay subgrid, and recommissioning of generators to provide dispatchable reserve.

Among the long-term solutions, DOE is the completion of transmission projects to upgrade submarine cable capacity and enable improved sharing of excess power generation across Negros and Panay.

It can be noted that the NGCP has completed the stage 3 of the Cebu-Negros-Panay (CNP) project, a major power transmission line project.

After facing delays at least seven times from the original completion date of December 2020, the backbone project was completed in March this year and was energized on April 8.

The backbone project will accommodate the transmission of excess power equivalent to the output of two 400-MW plants from Panay and Negros to Cebu.