Key Takeaway
A yellow alert means the grid's reserves are thin but demand is still being met. A red alert means supply isn't enough for demand, so rotational brownouts are likely. The DOE has warned of more alerts in the Visayas as El Niño continues into early 2027. To keep power on at home during a brownout, you need a battery: a grid-tie solar system without one shuts off too.
What do yellow and red alerts mean?
The National Grid Corporation of the Philippines (NGCP) raises an alert when the power plants available can barely keep up with demand. There are two levels:
| Alert | What it means | Will there be brownouts? |
|---|---|---|
| Yellow alert | The grid's spare capacity (operating margin) is below what's needed to cover the biggest plant suddenly tripping. | Not automatically. But if another plant trips, it can turn into a red alert. |
| Red alert | Available supply isn't enough to meet demand and keep the grid stable. | Likely. Rotational brownouts are used to keep the whole grid from collapsing. |
During a red alert, your electric utility, such as Meralco or your electric cooperative, carries out the rotational brownouts by cutting power to different areas in turns, usually announced on their Facebook page.
How often were there alerts in 2026?
- May 13 to 15: red alerts on both the Luzon and Visayas grids, after demand hit a record high while several plants were down. This led to rotational brownouts.
- May 29: the Visayas grid went on red alert again in the evening, with available capacity only slightly above peak demand.
- August 31: red alert on the Visayas grid from 5 p.m. to 10 p.m., with about 2,059 MW available against an expected peak of 2,305 MW.
Notice the timing: alerts usually fall in the afternoon and evening, when aircon use is high and solar plants are producing less.
Will there be more brownouts during El Niño?
PAGASA expects a very strong El Niño from October 2026 to January 2027, which means hotter days, more aircon use and less water for hydropower plants.
In October 2026 the DOE said the Visayas grid could face more red and yellow alerts if new power projects are delayed. It's counting on about 253 MW of battery storage by the end of 2026 and 293 MW of diesel plants by early 2027. For Luzon, the DOE's simulations show possible red alerts into next year, though not necessarily with brownouts.
In short: brownouts aren't certain, but the risk is real, especially in the Visayas. It's a good time to plan for them.
What can you do during a yellow or red alert?
- Use less power during alert hours. Set the aircon a degree or two warmer and delay laundry, ironing and the water heater until the alert ends.
- Charge phones and power banks early when an alert is announced.
- Check your utility's brownout schedule. Meralco and the electric cooperatives post rotational brownout schedules on their websites and Facebook pages.
- Unplug sensitive appliances like TVs, computers and aircon units when the power goes out, so they aren't hit by a surge when it comes back.
- Run generators outdoors only. Never run a generator inside the house or garage.
Will my solar panels keep the power on during a brownout?
It depends on your system:
| System | During a brownout |
|---|---|
| Grid-tie (no battery) | Shuts off, even when it's sunny. This is a safety feature that protects line workers fixing the grid. |
| Hybrid (with battery) | Switches to the battery and solar, usually so fast the lights barely flicker. |
| Off-grid | Not affected, because it isn't connected to the grid. |
So if brownouts are your main concern, you need a battery. Read more in What Happens to Solar Panels During a Brownout?
How big a battery do you need for brownouts?
For most homes, a 5 kWh battery keeps the essentials (ref, lights, Wi-Fi, fans and a TV) running through a typical 4 to 6 hour brownout. If you want a bedroom aircon on backup too, or brownouts in your area run all night, look at 10 kWh or more.
The 2026 red alerts lasted around 5 hours or more in the afternoon and evening, which is about what a 5 kWh battery for essentials is sized for. See How Big a Solar Battery Do I Need for Brownouts? to work out your own size.
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Get Free Solar QuoteCommon questions
What's the difference between a yellow alert and a red alert?
A yellow alert means the grid's reserves are thin but demand is still being met. A red alert means supply isn't enough to meet demand, so rotational brownouts are likely.
Does a yellow alert mean there will be a brownout?
Not automatically. A yellow alert is a warning. Brownouts usually only happen if it turns into a red alert, for example when another power plant trips.
Who decides where the rotational brownouts happen?
NGCP declares the alert and tells utilities how much power to cut. Your electric utility, such as Meralco or your electric cooperative, decides which areas lose power and when, and posts the schedule.
Will my grid-tie solar system work during a red alert brownout?
No. A grid-tie system without a battery shuts off when the grid goes down, even in full sun. You need a hybrid system with a battery, or an off-grid system, to keep power on.
How long will a 5 kWh battery last during a brownout?
It runs the essentials (ref, lights, Wi-Fi, fans and a TV) for about 4 to 6 hours. Adding an aircon cuts that time a lot, so homes that want aircon on backup usually need 10 kWh or more.
Sources
- Brownouts return as Luzon, Visayas grids hit red alert; here's what the terms mean
- EXPLAINER: Why rotational brownouts occur
- Red alert status up for Luzon, Visayas grids
- NGCP places Luzon, Visayas grids under red, yellow alerts
- Red, yellow alerts raised over Visayas grid
- Visayas grid at risk of further alerts if power projects delayed
- Very strong El Niño likely from October 2026 to January 2027, says PAGASA
- El Niño to emerge in June, intensify into strong to very strong condition by year-end: PAGASA