CEBU CITY, Philippines — The newly energized Toledo Battery Energy Storage System (BESS) is providing another layer of support to the Visayas grid as power supply remains tight against demand, Meralco PowerGen (MGEN) Thermal said.
MGEN Thermal President and CEO Arnel Santos said the tightness in the system is driven by growing electricity demand and the unreliability of some generating units.
“Una, demand is growing. At the same time, ang daming unreliability sa system,” Santos said on Wednesday, September 2, citing National Grid Corp. of the Philippines (NGCP) advisories showing several generating units that were either derated or under forced outage.
READ: More plant outages strain Visayas grid as DOE races to stabilize supply
As of Wednesday, NGCP placed the Visayas grid under red and yellow alerts as available capacity remained below projected demand.
NGCP estimated available capacity at 2,205 megawatts (MW) against a projected peak demand of 2,501 MW.
READ: Red, yellow alerts up in Visayas, Mindanao grid amid power woes
Several parts of Cebu have also continued to experience rotational brownouts as the power system operates with limited supply.
What the alerts mean
A red alert means available power is insufficient to meet demand and the grid’s required reserve, while a yellow alert means there is not enough reserve to cover a sudden loss of a generating unit.
READ: MGEN Cebu battery energy storage system phase 1 done by 2026
The alerts indicate that the grid has less room to respond when a generating unit goes offline or demand rises.
Against this backdrop, the Toledo BESS can provide additional power when the grid needs a quick response to changes in supply and demand.
READ: Power supply woes in Visayas, Mindanao extend to September
Added support
Erick Cabarrubias, MGEN Cebu site head, said BESS serves as “another layer of support” for the grid because it can respond faster than conventional generating units.
“If a feeder or a power plant suddenly shuts down, the BESS reacts first before other plants can come online,” Cabarrubias said.
READ: Cebu manufacturing push faces power crunch, says Capitol investment chief
Santos said the battery can also help during periods of high demand, particularly later in the afternoon when electricity use remains high while solar generation declines.
“So far, it’s operating as designed. Wala po kaming naging bulilyaso sa aming operation,” Santos said.
The first phase of the Toledo BESS has a capacity of 25 MW and 56.44 megawatt-hours (MWh), allowing it to deliver its rated output for about two hours before needing to recharge.
MGEN energized the facility on May 8, 2026, making it the first two-hour BESS facility in the Visayas.
Not a replacement
Cabarrubias said the BESS is designed to support, rather than replace, conventional power plants that can provide electricity for longer periods.
“This will not replace the baseload power plants kay gamay ra man siya (because it is small),” Cabarrubias said.
The facility’s 25-MW capacity, in particular, is only a portion of the gap between the usual available capacity and projected peak demand.
Cabarrubias said the BESS supports grid stability during frequency fluctuations, while diesel and thermal plants provide additional generation when power is needed for longer periods.
Santos said MGEN is also focused on keeping its existing generating units available through preventive maintenance and reliability investments.
“Malaking portion ng annual budget namin is dedicated to keeping the plant reliable, including ’yong mga plant maintenance namin,” Santos said.
One of MGEN’s Cebu facilities, Cebu Energy Development Corp. (CEDC), is currently undergoing a planned major overhaul as part of its regular maintenance cycle.
Santos said the overhaul includes checks on the plant’s turbine and boiler systems and is proceeding according to the schedule coordinated with NGCP.
More capacity planned
Santos said MGEN and Meralco continue to study opportunities to increase generating capacity as electricity demand grows, including projects involving liquefied natural gas (LNG), renewable energy, battery storage, and existing thermal generation.
“What I can assure you is may willingness mag-continuously invest ang Meralco at ang MGEN na i-grow ’yong generating capacity po namin,” Santos said.
The second phase of the Toledo BESS is planned to add another 25 MW and 56.44 MWh, with commercial operation targeted for June 2027, subject to regulatory clearances.