YELLOW ALERTS on the Visayas grid are possible due to thinning reserves, the Department of Energy (DoE) said in a power outlook briefing on Friday.

It cited the need to put the Luzon grid’s reserves on standby in the event reserves in the Visayas fall below advisable levels. Should more power be needed, the Visayas can draw power from Luzon via high-voltage direct current (HVDC) transmission links, though Luzon reserves may also be thin at times.

“HVDC should always be available to provide support, as outages outside of the provided maintenance schedule may result (in) the thinning of reserves in Visayas or Luzon, since both grids support each other at peak times of the day,” the DoE said in a statement.

Grids maintain a reserve in the event of power plant outages, with the typical level of reserves deemed prudent set at the capacity of the largest generating unit. Yellow alerts are triggered when that reserve level is breached. The system moves to red alert when power demand exceeds the level of power generated, making the rationing of electricity necessary.

Meanwhile, the DoE said it does not expect yellow alerts in Luzon and Mindanao, even after allowing for power plant maintenance.

“The availability of stable and reliable power supply is of grave importance. There should be no surprises this year, especially given our continuous battle against the COVID-19 pandemic, regions that have been affected by Typhoon Odette are rebuilding themselves, and of course, because we are in an election year,” Energy Secretary Alfonso G. Cusi said.

During the briefing, officials said that according to the Grid Operating and Maintenance Program (GOMP), generation companies must submit their proposed maintenance schedules in advance in aid of power supply-demand forecasting. Advance notice for maintenance activity required under GOMP is three years.

“In addition, sound forward planning would allow the energy family to identify potential issues and formulate appropriate contingency measures to prevent potential power interruptions,” the National Grid Corp. of the Philippines said. — Luisa Maria Jacinta C. Jocson