DOE: May 8 outage caused by tripped power line, not supply-demand situation

The Luzon-wide power outage last Wednesday was primarily caused by an overload of electricity that tripped the Biñan-Calaca power line, as pointed out by the National Grid Corporation of the Philippines (NGCP), and not by any discrepancy in the power supply and demand situation, the Department of Energy said Friday. While the demand peaked at 8,300 megawatts (MW) just before the widespread outage plunged many house and offices in darkness on May 8, the supply available to the Luzon grid could still accommodate what the system required at that time, Mylene Capongcol, director for the Department of Energy-Electric Power Industry Management Bureau, told GMA News Online on Friday.. “Peak demand in Luzon was at 8,300 MW [that day] pero kakayanin pa yun i-supply. Ang nangyari nung May 8, nag-trip ang [Biñan-Calaca] line at ang Calaca power plant pero hindi pa matukoy ang problema kung bakit nag-trip,” Capongcol said. Power lines trip when supply is lost, or when the current is too strong, or when there is a problem in on the generator side, according to a DOE reasearch specialist. This in turn causes increased loads on other lines that in turn causes those lines to also trip. “Dapat ma-isolate 'yun, kaso baka may hindi nag-function kaya nadamay ang ibang power plants. But that’s still under investigation,” she added. Luzon was on “red alert” that day, according to the Energy official, noting the Luzon grid lost about 40 percent or 3,700 MW of the supply after the grid lost the input from the power plants. On average, Luzon has 1,280 MW of reserves which could no longer meet the the supply-demand gap, she said. Six power plants on May 8 tripped, causing a Luzon-wide power outage. Involved were the Sta. Rita, San Lorenzo and Ilijan power plants in Batangas, as well as those in MaubanMauban, Quezon and Sual in Pangasinan. “Wala na ang supply dahil anim na power plants ang nawala, hindi na kayang ma-meet ang demand kaya nagkaroon ng manual load tracking o pag-cut ng supply ng kuryente sa ilang consumers kaya kalahati ng franchise area ng Meralco ay walang kuryente, ganun din sa ibang lugar,” Capongcol said. On Thursday, the Philippine Chamber of Commerce and Industry (PCCI) urged the government to fast-track the investigation on what tripped the the Biñan-Calaca power line and what caused the other power plants to follow after the Calaca power plant tripped. “Our concern is baka maulit... Until we know the cause, there will be doubts,” PCCI chairman Edgardo Lacson said in a separate interview with GMA News Online. “Kaya dapat tignan ng government agad kung ano ang dahilan. “May theory na ang national grid ay walang parallel lines sa existing line, kaya nagkaroon ng widespread power interruption,” Lacson added. 'A lot' lost According to the PCCI official, the business sector on Wednesday lost “a lot” during the power disruption. “Five hours 'yun. [The losses] cannot be measured by percentage or value, but definitely malaki ang nawala sa businesses nung araw na 'yun,” he said. “Sa manufacturing, matagal mag-restart ang mga factories. Sa mga restaurants, malaking bagay ang kuryente dahil sa mga freezer na storage ng food. On service-oriented businesses, how can they deliver transactions kung walang kuryente, they don’t have generators,” Lacson added. As of 11 a.m. Thursday, power reserve was at 627 MW, which is still below the contingency reserve of 647 MW as the Calaca power plant in Batangas and and the Quezon power plant in Quezon were still offline, according to Energy Department data. The National Grid requires 1500 MW to 1600 MW of reserves. “Noong Wednesday morning, hindi agad nakapasok ang Quezon power plant kaya mababa ang power reserve natin. Nakapasok siya noong gabi, kaso nawala ulit dahil nag-uuulan sa area, baka may natamaan sa plant. Ngayong umaga, nakapasok na ulit ang Quezon power plant kaya normal na ang operation,” Capongcol said Friday. DOE data also showed the Luzon Grid has 12,765.7 MW in installed capacity from existing power plants, but only 8,825 MW is the available capacity against the average demand of 8,100 MW. DOE senior technical specialist Norman Vincent Martirez cited three reasons why some plants are not able to supply the grid: forced outage, low steam pressure and maintenance outage. Forced outage occurs when “some mechanical parts of a power plant breaks down or when there is an unplanned shutdown,” he said. “Most hydroelectric power plants are on maintenance during summer due to low hydro capability, and these are planned. On the other hand, geothermal plants depend on the steam pressure coming from the ground,” Martirez added. Capongcol noted that power plants do not also run simultaneously. “Not all will operate at the same time. Hindi sabay-sabay itinatayo ang mga 'yan, kaya iba-iba ang maintenance schedules. 'Yung iba naka-shutdown. Ang hydro power plants ‘pag summer, wala talaga. Ang iba naman naka-standby tapos i-ko-kontrata na lang ng NGCP,” she said. Ealier, the DOE said the Luzon grid needs a total additional capacity of 10,500 MW onwards to 2030 and a 600 MW new capacity is needed starting 2016 to meet the demand and required reserve. — VS, GMA News