Power generation companies reported to the Energy Regulatory Commission (ERC) that the unplanned outage of Sual Units 1 and 2 and Masinloc Units 1 and 2 that led to last Monday's 'red alert' notice originated from the tripping of transmission lines.
There were seven generating units with a total capacity of 3,401 megawatts (MW) that were on unplanned outage, and three generating units with a total of 226MW deration.
On late Tuesday, the ERC issued an advisory stating that the National Grid Corporation of the Philippines (NGCP) had told the agency that the reason why the Luzon grid was placed on red alert was because of 'major generation inadequacy.'
On the other hand, the generating units indicated in their reports that the reason for the unplanned outage was due to the tripping of NGCP's two transmission lines.
Sual 1 and 2, for instance, tripped due to an 'external fault after Bolo-Nagsaag 500 kilovolt [kV] line of NGCP trip that caused the system under frequency.'
Masinloc 2 and 3 units, meanwhile, were 'affected by double outage of Bolo-Nagsaag 500kV Line 1 and Line 2.'
'Worthy to note is that four out of the seven generating units reported that the outages were due to the tripping of Bolo-Nagsaag 500kV transmission lines 1 and 2 on September 11 at 7:25 a.m. On the other hand, the remaining three generating units were already on outage prior to the occurrence of the grid tripping incident,' said the ERC.
The agency said it would verify the reports submitted by the NGCP and that of the power generation companies, including the actions done to get it back online.
'Noting the fact that 58 percent of the capacity on outage was due to the September 11 Bolo-Nagsaag 500kV transmission line tripping incident, the ERC will look into the cause of the tripping and actions taken by the NGCP to repair the subject line, including the reasons why the generating units were not able to get back online with the restoration of the transmission line,' the ERC said.
The NGCP, for its part, said earlier that the activation of System Integrity Protection Scheme (SIPS) did not lead to the red alert incident. 'SIPS [was conceived] so as not to worsen the problem. As part of that precaution to maintain the integrity of the grid, Sual and Masinloc was disconnected,' it said.
Gatchalian demands solutions
Senate Energy Committee Vice Chairman Sherwin Gatchalian, meanwhile, urged the Department of Energy (DOE) for aggressive implementation of solutions to address the issue.
'Such power interruptions are unacceptable at a time when the country is in dire need of a steady supply of energy as we all work toward sustaining the country's economic recovery. The DOE must ensure a steady supply of energy necessary for our businesses and organizations, particularly MSMEs [micro, small and medium enterprises] and our learning institutions, to implement unrestricted operations especially during summer,' he said.
'All power plants should be built on time and generation companies should follow the maximum allowable days that plants can be on outage,' Gatchalian said in reiterating solutions to rotational power outages that were proposed to the previous administration.
DOE Secretary Raphael Lotilla, for his part, said his office would also validate the reports.
'We assure the public that the DOE is verifying the cause of the forced outages as there appears to be no fuel supply constraints.
A team from the DOE will conduct actual physical spot checks and validate the condition of the transmission lines and the affected power plants,' the energy chief said.
Gatchalian also reminded the NGCP of its obligation to fully contract the required reserves as mandated by a DOE circular.
For the long term, Gatchalian further proposed the energy department must ensure timely construction of power generation plants in the country to ease any possible tightness in supply in the future and address any spike in electricity demand and address any delay caused by permitting by fully implementing the Energy Virtual One Stop Shop (EVOSS) Act.
Also, he said the DOE must ensure the full implementation of the Transmission Development Plan (TDP) designed to ensure the build out of the grid infrastructure to prevent stranded power plants.
Further, the government should also ensure that the Grid Operating and Maintenance Program (GOMP) or the schedule of planned outages of power generating plants as well as transmission facilities is followed, Gatchalian said.
The red alert status for the Luzon grid took effect at 1 p.m. last Monday. It was lifted from 5 p.m. to 8 p.m., the grid was placed on yellow alert.
When reserves fall below ideal levels, a yellow alert is placed over the grid. When supply-demand balance worsens, a red alert, which points to severe power deficiency that may lead to rotating power interruptions, is declared.
But there were no reported brownouts in the franchise area of the Manila Electric Company (Meralco) because it has advised early on its Interruptible Load Program (ILP) participants of possible manual load dropping (MLD). The ILP participants may run their facilities to allow more grid capacity to serve other customers.
August spot market price drop
Meanwhile, the Independent Electricity Market Operator of the Philippines (IEMOP) said electricity spot market prices dropped by P1.66/kWh to P7.27/kWh for the August billing period due to an increased supply margin equivalent to 844 MW.
The lower market price also resulted in an uptick in customer purchases in the spot market averaging about 14 percent of their energy consumption as compared to the 8.3 percent purchases in the preceding month.
However, for the first 10 days of September, peak demand has continuously risen from July. Peak demand in Luzon increased by 187 MW to 11459 MW, while in the Visayas, the demand peaked at 2225 MW, higher by 34 MW.
'The recent planned and forced generator outages have also resulted in an increase in spot market prices and very recently, an issuance of red and yellow alerts in the Luzon grid. As such, IEMOP reiterates the importance to save up and efficiently manage our electricity consumption that will not only save on our electricity cost but also, immediately help in mitigating reduced supply margins,' it said.