MANILA (UPDATE 2) -- It's not just the Luzon and Visayas islands that have to deal with electricity issues as the country's power grid operator declared a Yellow Alert over Mindanao as well on Wednesday, April 24. 

The National Grid Corporation of the Philippines (NGCP) said the following alerts were in effect:

LUZON GRID

𝐑𝐞𝐝 𝐀𝐥𝐞𝐫𝐭

3 p.m. - 4 p.m. 

𝐘𝐞𝐥𝐥𝐨𝐰 𝐚𝐥𝐞𝐫𝐭

1 p.m. - 3 p.m. 

4 p.m. - 10 p.m. 

The NGCP lifted the Red Alert for the Luzon grid at 4:05 p.m. but maintained the Yellow Alert from 4 p.m. to 11 p.m.

VISAYAS GRID

𝐑𝐞𝐝 𝐀𝐥𝐞𝐫𝐭

12 nn - 5 p.m. 

6 p.m. - 8 p.m.

𝐘𝐞𝐥𝐥𝐨𝐰 𝐀𝐥𝐞𝐫𝐭

10 a.m.-12 nn

5 p.m. -6 p.m. 

8 p.m. -9 p.m. 

MINDANAO GRID

𝐘𝐞𝐥𝐥𝐨𝐰 𝐀𝐥𝐞𝐫𝐭

10 a.m. - 4 p.m. 

The NGCP later said that it had lifted the Yellow Alert for Mindanao at 3:09 p.m.

A red alert means rotating brownouts can be expected as the power supply is insufficient to meet consumer demand and the transmission grid’s regulating requirement, the power grid operator said.

A yellow alert means rotating brownouts are possible as the operating margin is insufficient to meet the transmission grid’s contingency requirement.

The NGCP said the available capacity in Luzon is  14,241 megawatts, while peak demand is at 13,643MW.

For the Visayas, the available capacity is 2,462MW, while peak demand is projected to be 2,525MW. 

For Mindanao, the available capacity is 2,761MW while peak demand is 2,614MW. 

The NGCP said several power plants across the country are on forced outage, and others are operating on lower or derated capacities. 

'WORST YET TO COME'

The Department of Energy said the electricity demand has been rising as temperatures also kept climbing starting last month.

DOE Asec. Mario Marasigan said the main reason for the current situation is a combination of factors including the unavailability of many plants and intense hot weather.

Meralco Spokesman Joe Zaldarriaga meanwhile said the worst is yet to come as temperatures are still expected to rise in May.

Zaldarriaga said Meralco will prepare everything, including the interruptible load program and demand-side management measures but once supply becomes deficient, it will have to resort to manual load dropping which means power interruptions for some of its customers.

Meralco said it asked its commercial and industrial customers under the Interruptible Load Program (ILP) to de-load from the grid to help ease the demand.

NGCP spokesperson Cynthia Alabanza said all the grids live by the day as authorities cannot make assurances that the situation will improve soon.

Around 400MW of power from the generators of big companies like malls and factories can be used to ease the burden on the Meralco system, preventing power interruption to ordinary customers.