Guerrilla Solar vs Grid Stability: The Growing Clash Over Rooftop Power in the Philippines
- May 13, 2026
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Across social media, frustration has been mounting over reports that the Manila Electric Company (Meralco) wants tighter regulation of so-called “guerrilla solar” installations — rooftop solar systems installed without permits, inspections, or registration under official net-metering programs.
To many Filipinos struggling with soaring electricity costs, the move sounded like an attack on ordinary households simply trying to cut their bills. Online discussions quickly erupted, with some accusing the utility giant of protecting profits instead of supporting renewable energy adoption.
But behind the outrage lies a more complicated issue involving grid stability, safety standards, energy forecasting, and the difficult balancing act of integrating renewable energy into an aging power system.
(Also read: DOE Supports Electricity VAT Relief As Lawmakers Push Lower Power Costs)
Meralco’s Solar Standards Push & Public Backlash
In early May, Meralco called on the government to tighten oversight of rooftop solar systems, pushing for clearer technical standards on equipment and stricter regulation of unauthorized or improperly installed units, which it said could pose risks to consumers and the power grid.
Public reaction online was swift and emotional. Many Filipinos interpreted the proposal as an attempt to discourage rooftop solar adoption. Some commenters accused Meralco of trying to preserve electricity sales amid growing consumer interest in solar panels and battery systems.
“At bakit kailangan magpa-register, magpa-install ng solar? Hindi pa ba sapat na ang solar installer ang may necessary trade documents?’ (And why is there a need to register before installing solar? Isn’t it enough that the solar installer already has the necessary trade documents?),” a Reddit user commented.
“Meralco worrying about profits?” another user wrote.
The controversy also comes at a time when more Filipinos are becoming energy-conscious due to repeated warnings of possible yellow and red alerts during the dry season because of heightened electricity demand.
Why More Homeowners Are Installing Solar
For many households, installing rooftop solar is not just an environmental choice but also a practical way to manage rising electricity costs.
Some so-called “guerrilla solar” systems operate fully off-grid, meaning they do not interact with Meralco at all. Others, however, remain connected to the distribution network but are installed without proper registration or compliance with net metering rules.
With on-grid solar power, homeowners can benefit from net metering, a program under the Renewable Energy (RE) Act of 2008 that allows excess electricity generated by solar panels to be exported back to the grid in exchange for bill credits. This helps maximize savings, especially for households that produce more electricity during the day than they consume.
The Department of Energy (DOE) adds, “What is even greater to this cause is that end-users can help mitigate the effects of climate change through the use of clean energy technologies. It will also contribute to lessening the country’s dependence on costly imported fossil fuels.”
For some homeowners, energy security is another major consideration. Hybrid solar systems, which combine grid connection with battery storage, can continue supplying power during outages.
Still, solar home installations come with several drawbacks depending on the system type. Grid-tied solar systems do not operate during brownouts for safety reasons, meaning households still lose power when the grid goes down, and savings are highly dependent on how much electricity is used during daytime hours.
Hybrid solar systems are more expensive due to added storage components, and the batteries typically require replacement after about 8 to 12 years.
Meanwhile, off-grid systems provide full energy independence but come with the highest upfront cost, as they require more solar panels and large battery banks to reliably meet household energy needs.
Why Meralco Wants Tighter Rules
Under the RE Act, the net metering program allows customers to install RE systems of up to 100 kilowatts (kW) and export excess electricity to the grid. According to Meralco vice president Lawrence Fernandez, despite the 100-kW cap, many commercial establishments have installed much larger rooftop solar systems outside the program, adding roughly 370 MW more, with average installations around 700 kW. This brings the total registered solar capacity in Meralco’s coverage area to over 500 MW.
This raises concerns that bigger solar adopters outside the program potentially limit proper oversight and integration. It also suggests that policy may not be fully aligned with the scale of current solar uptake, creating grid inefficiencies.
In effect, Meralco’s concerns are focused on grid-connected rooftop solar, particularly systems that are unregistered or exceed program limits, since these directly affect demand forecasting and grid stability.
Citing data from the Institute for Climate and Sustainable Cities (ICSC), Fernandez noted that about one-third of rooftop solar installations in Metro Manila, or roughly 265 MW, may not be officially recorded. This lack of visibility can lead utilities to overestimate electricity demand and procure more power than is actually needed, potentially affecting grid planning, efficiency, and contributing to higher generation costs for consumers.
Since there are many unknown or undocumented solar PV systems within the Meralco franchise area, it becomes difficult for the utility to accurately plan for fluctuations in supply and demand. When these systems are not visible to the grid operator, Meralco may have to secure additional backup power to cover unexpected shortfalls or reduce supply when there is excess generation. This uncertainty complicates network planning and operations, and it can also lead to additional costs that ultimately affect overall system efficiency.
Another core issue with unauthorized grid-connected solar PV installations within the Meralco franchise area is that they may lack essential safety and compliance features required for proper integration with the distribution network. These systems must be equipped with automatic shutdown mechanisms during grid outages to prevent backfeeding, which can pose serious risks to linemen working on power lines. Without proper authorization and inspection, there is also a higher likelihood that these installations are done incorrectly or unsafely, increasing the risk of electrical faults, equipment damage, and potential harm to both the household and the broader grid.
“As for the estimated 370 MW of registered rooftop solar capacity within Meralco’s franchise area that is not part of the net metering program, typically installed at malls and other large commercial establishments, this is not really a problem, and to be fair to Meralco, the company did not suggest it was,” observed Manila Times columnist Ben Kritz. “So long as Meralco knows about it, it can adjust its demand profile accordingly and keep power flowing smoothly to everyone else.”
Additionally, Kritz pointed out that while streamlining the net metering process aims to make rooftop solar more accessible, it does not automatically translate into large-scale expansion. Grid operators such as Meralco still have to manage the variability of solar generation, which fluctuates with weather and time of day. Higher levels of net metering penetration can increase the complexity of balancing supply and demand on the distribution network, affecting system stability.
The April 2025 Iberian Peninsula blackout, which disrupted electricity supply across Spain, Portugal, and parts of southern France and affected millions of users, highlighted how quickly instability can spread in a highly interconnected power system. Reports from the period indicate that Spain was sourcing a large share of its electricity from solar at the time, and a sudden imbalance between generation and demand contributed to a voltage spike that triggered protective shutdowns and a cascading failure across parts of the grid.
The National Grid Corporation of the Philippines (NGCP) also warned that a heavy dependence on intermittent sources like solar power can create operational risks for the grid, particularly through sudden fluctuations in frequency and voltage. If not properly managed, these imbalances may trigger protective measures such as under-frequency load shedding or even rotating power interruptions in affected areas.
This concern was reflected in an early January 2026 incident in parts of North Luzon, where voltage fluctuations were reported due to unstable RE output in the region. The event underscored how rapid changes in RE generation can disrupt voltage levels and overall system stability, prompting NGCP to implement corrective measures to maintain grid reliability.
(Also read: The Fossil Fuel Reality Behind the Energy Transition)
Between Consumer Frustration and Grid Reality
The debate surrounding rooftop solar regulation reflects a growing misunderstanding between consumers and the utility sector. For many households, solar adoption has become a direct response to rising electricity costs, and proposals for tighter oversight are often interpreted as resistance to renewable energy. On the other hand, utilities like Meralco and grid operators such as NGCP are tasked with maintaining system reliability in an environment where solar generation is inherently intermittent and rapidly expanding.
This tension is further complicated by structural limitations in the Philippine power system. The grid was not originally designed for high levels of distributed generation, and significant upgrades are required to fully accommodate large-scale rooftop solar integration. However, these improvements come at a cost. At the same time, universal charges such as the Feed-in Tariff Allowance (FIT-All) and the Green Energy Auction Allowance (GEA-ALL) already contribute to electricity bills. These layers of cost highlight the financial pressure involved in transitioning the energy system.
While solar adoption offers long-term sustainability benefits, its intermittent nature means it cannot yet fully replace conventional baseload generation. A cautious, phased approach—combining renewable expansion with continued reliance on legacy fuels and grid modernization—is necessary to balance affordability, reliability, and the realities of infrastructure readiness.
Sources:
https://www.reddit.com/r/SolarPH/comments/1t6n6rt/the_manila_electric_company_meralco_warns_against/
https://www.reddit.com/r/pinoy/comments/1t34527/do_you_think_tama_itong_mungkahi_ng_meralco/
https://www.gmanetwork.com/news/money/economy/984505/power-alert-level/story
https://www.ecoflow.com/ph/blog/off-grid-solar-system-guide
https://legacy.doe.gov.ph/net-metering-home
https://www.philstar.com/headlines/2026/01/08/2499519/ngcp-welcomes-terra-solar-project-but
https://www.manilatimes.net/2026/05/07/opinion/columns/a-brewing-solar-controversy/2337415
https://en.wikipedia.org/wiki/2025_Iberian_Peninsula_blackout
