THE Department of Energy (DOE) expects the issuance of yellow alert warnings to continue for the rest of the year, following Monday’s rotational brownout after the tripping of a transmission line that disrupted operations at a major power plant.
“We have potential yellow alerts for the entire month of May. Now, the way that was computed was a worst-case scenario. We assumed that Ilijan power plant will not yet come in. If that power plant comes in, then the yellow alert warnings will be reduced,” said DOE Undersecretary Rowena Guevara at a news conference on Tuesday.
Based on the updated Luzon grid power demand outlook, DOE said the yellow alert could be issued on weeks 18 to 21 of May, weeks 22 to 24 in June, weeks 32 to 34 in August, weeks 35 and 38 in September, weeks 39 and 42 in October, and week 47 in November.
A yellow alert means thin power reserve.
Guevara stressed that the projected 15 yellow alert warnings for the remainder of 2023 could happen if the Ilijan power plant is not able to come on line by May 26, if the committed power projects’ target commercial operations do not happen, and if there are further delays in transmission projects.
Based on the same projection, there are no red alert warnings. Guevara, however, is not discounting the possibility that last Monday’s red alert—the first for the year—could recur.
A red alert status is issued when power supply is insufficient to meet consumer demand and the regulating requirement of the transmission grid.
The National Grid Corporation of the Philippines (NGCP) has been instructed by the DOE to explain the circumstances that caused the outage affecting over 300,000 customers of the Manila Electric Company (Meralco).
NGCP’s initial investigation on the sequence of events that led to the red alert in Luzon grid last May 8 showed that the Bolo-Masinloc 230kV Line 2 tripped. This line is N-1, or operates with a redundancy. The load carried by Line 2 was automatically transferred to Line 1 when the former tripped. Each of Lines 1 or 2 is more than capable to singularly carry the entire loading of the Bolo-Masinloc 230kV facility at any time.
Thereafter, two of three Masinloc Units tripped. Together with other units already on forced outage, total power lost to the grid was 1,354MW.
“Given the N-1 contingency in place at NGCP’s Bolo-Masinloc Line, and the automatic transfer of loads from Line 2 to Line 1, the tripping of 2 Masinloc units was both unexpected and undesirable,” the NGCP said in a statement.
As of press time, Unit 1 of Masinloc was successfully and fully reintegrated to the grid, and Unit 2 was integrated at a derated capacity of 150 MW.
“We are coordinating with Masinloc power plant and other grid-connected generating plants on the way forward and to ensure that protection settings are in sync between generating plants and NGCP,” added NGCP.
Greenpeace weighs in
Environmental group Greenpeace campaigner Khevin Yu observed that the country’s power supply is “highly centralized, relying on big power plants,” making it vulnerable to incidents like unscheduled maintenance and equipment breakdown, and at risk of damage due to strong typhoons and other climate impacts.
“As El Niño looms along with more power outages and shortages, we reiterate the fact that our fossil fuel-dependent energy system remains unreliable, and that we need to expedite a just transition to renewable energy,” he added.
“Our energy mix is still dominated by coal and other dirty energy sources, which have proven to be inflexible during times of high demand. This is the same thing we experienced in the past few years, and it’s only going to get worse and more costly for consumers,” said Yu in a statement.
Senate Energy Committee Vice Chairman Sherwin Gatchalian said the DOE and the Energy Regulatory Commission (ERC) should hold the NGCP accountable should they find fault or negligence on the part of the transmission concessionaire.
“There can be no valid excuse for NGCP for its failure to conduct a comprehensive audit of its facilities, given that system disturbances have already led to brownouts in Panay and Negros Islands just a month ago.
DOE Secretary Raphael Lotilla said the NGCP’s performance will be taken into account in the rate rebasing review being undertaken by the ERC.
“The next step for us is to use this audit report as a basis…it is not a case of blame throwing. What we want to do is to establish in an objective manner, what are the weak links, what are the problems in the transmission system and what can we do in order to address these problems,” said Lotilla.
He said the first NGCP audit is a review of the grid operator’s financial capability, “but with observations as well on the technical side.”
The DOE, he said, “will follow that with a regulatory performance audit and by a contract performance review, which is to be conducted by PSALM and Transco as the counterparties to the NGCP concession agreement.”
Lotilla stressed that the DOE and other agencies have helped NGCP fast-track the completion of long-delayed transmission projects and free up stranded power supply.
“Notwithstanding these efforts, these projects still have not been completed. The recent prolonged power outages in Panay and Negros, and the power interruption experienced yesterday have been traced principally to inadequacies in the transmission system,” said Lotilla.