Mindanao blackouts up to 6 hours

GENERAL SANTOS CITY, Philippines – Brownouts lasting up to 6 hours are expected in Mindanao on Friday, March 15, as the deficit in the problematic power supply of Mindanao goes down further by 309 MW.

The National Grid Corporation of the Philippines (NGCP) said system capacity in the Mindanao grid is now merely 825 MW, far below the 1134 peaking load in the island.

Hardest hit

Among the hardest hit is the South Cotabato II Electric Cooperative (Socoteco II), which issued an advisory Thursday that two power interruptions lasting 3 hours each will be implemented in its franchise area on March 15.

The Socoteco II franchise area covers General Santos City, Sarangani province, and the towns of Polomolok and Tupi in South Cotabao. In Iligan City, brownouts have lasted up to 2 hours. 

In Zamboanga City, daily rotating brownouts lasts up to 7 hours. The city’s 54MW supply from the grid is 25MW short of its peaking demand of 79MW.

Only Davao and Cagayan de Oro have been spared from rotating brownouts so far.  The distribution firms in the cities are privately owned and have embedded diesel-fired power generators.

De-rating of power plants

NGCP communications personnel Bambi Capulong said the reduced capacity is due to the de-rating of power plants being operated by the National Power Corporation (Napocor).

She refused to disclose which Napocor power plants ran were de-rated. However, energy officials have warned that a mild dry weather spell could affect the water level in Lake Lanao.

Napocor still owns and operates the Agus and Pulangi river hydroelectric plant complexes.  The two hydroelectric dam complexes have a combined rated capacity of more than 900MW.

During the height of the 2010 power crisis in Mindanao, however, the combined actual capacity of these two plants was reduced to less than 500MW due to reduced water supply in Lake Lanao and the Pulangi River.

The Agus River hydroelectric plants, a complex of six run-of-river cascading plants, were built in the 60’s and 70’s. The Pulangi hydro power plants, on the other hand, were built in the 80’s.

The power supply in Mindanao has been erratic during the last 5 years. This has caused NGCP to issue daily advisories on available capacities and advising on distribution utilities by the hour.

Brownout schedules of distribution utilities, in turn, have also become unpredictable.

Socoteco II manager Rodolfo Ocat said that the increased load curtailment advisories from NGCP has caused its scheduled rotating brownouts to go into disarray. The power cooperative said that they have decided to divide the city into more than 45 feeder areas and two groups to avoid system overloading.

Socoteco II has a peaking load of 112MW.  Supply from Napocor is only 46MW.  It is sourcing another 35MW from Aboitiz-owned Therma Marine, Inc.- Rappler.com