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‘Imbalance‘ led to Mindanao blackout




Posted on March 15, 2014


A CONFLUENCE of events caused last month's Mindanao-wide blackout and needed repairs to damaged facilities will mean that the situation on the island will only improve by mid-year, Energy officials said on Friday.

"By June 4, everything will be restored. STEAG's first 105-megawatt (MW) unit will be back on May 4 and the other one in June. So power situation will normalize in June," Energy Undersecretary Raul B. Aguilos told reporters in a briefing.

STEAG State Power, Inc.'s 210-MW coal-fired power plant supplies about a fifth of the island's total supply. Technical issues at the facility that coincided with a transformer fault at the 80-MW Agus 1 hydroelectric power plant was said to be the trigger for the Feb. 27 outage.

"The blackout that happened in Mindanao was due to a demand and supply imbalance caused by a combination of events," National Transmission Corp. President Rolando T. Bacani said during the same briefing.

Specifically, these were "the unwanted loss of generation of the STEAG units ... [and] the defective equipment of Agus 1," Mr. Bacani said. "If these events happened on their own, the system would not collapse. They happened simultaneously, that's why it collapsed."

A load reduction starting 3:51 a.m. at the STEAG plant, Mr. Bacani explained, led to an abrupt increase in generation demand. The Agus facility subsequently tripped, which led to the tripping of all other power plants connected to the Mindanao grid.

SPI President Bodo Goerlich stressed that a gradual load reduction by itself would not cause the grid to fail.

"The fluctuation of the load of power plants happens from time to time and the over-all effect is managed by adjusting either the supply or demand of the grid. We have in the past experienced such a situation and it did not cause a massive blackout and total collapse of the grid," Mr. Goerlich explained in a statement.

The firm, he said, is working "round-the-clock" to fast track the restoration of the plant.

"We empathize with those that are affected by the Mindanao power supply shortfall and rest assured that we are doing our best to restore the units back to the grid and help alleviate the island's precarious power supply condition," Mr. Goerlich said.

"We are also carrying out all maintenance activities on other systems of the plant that were originally planned/scheduled for August 2014. Thus, there will no more outage in August 2014" he added.

Agus 1 plant owner and operator National Power Corp. (Napocor), meanwhile, said the facility was "very sensitive to the disturbance".

"The capacity voltage transformer was scheduled for replacement even before the tripping," Napocor President Gladys Cruz-Sta. Rita noted at the briefing.

The Agus 1 plant is part of the Agus-Pulangi hydroelectric power plant complex that supplies more than half of Mindanao's power needs.

Asked who would be liable, the Energy department's Mr. Aguilos said: "We would rather focus on fast-tracking the restoration. We are not looking at sanctions. And it is worthy to take note that STEAG also had huge losses with the coal plant offline."

Some areas in Mindanao continue to experience two to three hours of rotating brownout, he said, but other areas already have a steady supply of power "because the embedded and excess capacities are being utilized".

He noted that the construction of more power plants was crucial, and said electric cooperatives on the island needed to be "more resourceful in looking for additional capacities". Upcoming commercial operations of Therma South, Inc.'s 300-MW coal-fired power plant were also welcomed.

"We expect that (the Therma plant) to be online late this year or early next year. Having two base load plants in Mindanao will help improve the supply," Mr. Aguilos said.

Business groups in Mindanao, however, said they remained skeptical as the government had yet to make good on plans to improve the power situation.

"The Mindanao Business Council will convene a forum to condemn the actions of NGCP and PSALM (the Power Sector Assets and Liabilities Management Corp.) on the problems we are having in Mindanao right now," Mindanao Business Council Chairman Vicente T. Lao said.

On official from the Dipolog Chamber of Commerce claimed incidents like the massive outage could have been prevented if there was a "definitive energy plan".

"We expect that the lingering power situation will be prolonged until a definitive energy plan is in place, not only for Mindanao, but for the country as a whole, which we in the business sector have been clamoring for the longest time," Chairman Edwin B. Capili said.

"With skepticism, we foresee the problem of power disruption to persist due to lack of base load power plants. Until then, the situation will get worse before it even gets better," he added.

National Grid Corp. data showed that Mindanao on Friday had a 334-MW deficiency, with peak system demand of 1,272 MW and capacity of only 938 MW.

The system-wide Mindanao outage occurred less than a year after significant parts of Luzon experienced a 10-hour blackout. The cause of that outage was attributed to a transmission line malfunction. -- Claire-Ann Marie C. Feliciano