NGCP: Power supply improves, but risk of brownouts remains

THE Visayas power situation has improved with most major power plants back online, but the region remains vulnerable to rotational brownouts because of aging generating facilities and insufficient new capacity, an official of the National Grid Corp. of the Philippines (NGCP) said Tuesday, Sept. 29.

Amado Otarra III of NGCP Visayas said several large plants went on forced outage in July and August, triggering rotational brownouts as available supply fell below demand.

At the time of the interview, two major plants remained offline: the 150-megawatt (MW) Panay Energy Development Corp. (PEDC) Unit 3 in Iloilo City and the 103-MW Kepco SPC Power Corp. (KSPC) Unit 2 in City of Naga, Cebu.

Plant outages

KSPC was expected to return within the day, while PEDC Unit 3 was expected to return by Nov. 9 after a major system upgrade.

With most major plants back online and the Visayas able to import up to 450 MW from Mindanao, no yellow alert had been issued as of Tuesday. The last alert was issued Monday before one of the region’s largest baseload plants returned to service.

However, Otarra said the improvement remains temporary.

The Visayas grid cannot currently stand alone without imported electricity because some of its baseload plants are already 16, 20 or 30 years old.

Growing demand

Cebu accounts for almost half of the Visayas’ power demand, while demand continues to grow with new condominiums, malls and other developments.

Solar power helps augment supply during the day but cannot generate electricity at night, when longer rotational brownouts usually occur.

If another major plant goes offline and sufficient power cannot be imported from Luzon or Mindanao, NGCP may again implement manual load dropping to protect the grid.

Without it, a wider interruption or even a total Visayas blackout could occur, Otarra said.

He said the region may continue experiencing power supply problems next year and possibly for the following two years unless new generating capacity is added.

More generation

The Department of Energy (DOE) is encouraging investors to build additional power plants.

Otarra also cited plans for power barges that could provide about 200 MW. The barges would run on diesel and could help augment supply without necessarily lowering electricity costs.

The DOE has also been considering more than 200 MW of temporary generation capacity while permanent projects are developed.

Demand is expected to ease in the fourth quarter, or the months of October, November and December, as cooler weather reduces air-conditioning use.

Otarra said December demand could be 100 to 150 MW lower than levels during peak months, despite additional Christmas-light consumption, because modern LED lights use less electricity.

Impact on water supply

The power interruptions have also reduced Metropolitan Cebu Water District (MCWD) production.

Rainier Quiñones, manager of MCWD’s production and distribution, said the utility’s normal capacity is about 290 million liters per day (MLD), but two- to three-hour rotational brownouts over the past three to four months reduced average production to 268 MLD.

Production has recently improved to about 272 to 273 MLD as brownouts eased, but interruptions continue to affect parts of mainland Cebu, Mactan, Consolacion, Compostela, Liloan, Talisay and Mandaue.

MCWD has asked Visayan Electric to exempt its 169 pumping stations from rotational brownouts.

Quiñones said the short notice given by NGCP to Visayan Electric and then to MCWD makes it difficult to deploy generators, particularly at pumping stations without backup power. / CAV