“Guerilla” Solar Installations Discovered, Need To Be Controlled, Says Philippine Power Distributor
A solar array in Quezon City. (Photo by author)
May 4, 20262 hours
Raymond Tribdino
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Manila Electric Company, commonly known as Meralco, is the largest private electric distribution utility in the Philippines, serving Metro Manila and surrounding provinces with a franchise area that covers more than seven million customers. Its role is comparable to a regulated distribution utility in the United States, responsible for delivering electricity from generation sources to end users, maintaining grid stability, and enforcing interconnection standards.
Against this backdrop, the company is now pressing the Philippine government to tighten technical requirements for rooftop solar systems and the contractors installing them, citing a rapid expansion of unregistered installations that operate outside formal regulatory oversight.
At a recent Senate hearing, Meralco vice president Lawrence Fernandez supported proposed amendments to the Renewable Energy Act aimed at streamlining the country’s net metering framework. Net metering in the Philippines, much like in several U.S. states, allows distributed solar users to export excess electricity to the grid in exchange for bill credits, but the process has been widely criticized for its permitting complexity and long approval timelines.
In a report that appeared in the Manila Standard, Meralco said there are more than 20,000 registered rooftop systems with a combined capacity of about 170 megawatts. It estimates that an additional 370 megawatts exist in the commercial sector alone without formal registration. A separate analysis by the Institute for Climate and Sustainable Cities, using satellite imaging and cross-referenced grid data, suggests that roughly one-third of solar rooftops within Meralco’s service territory fall into this unpermitted category, often referred to locally as “guerrilla solar.”
The technical concern centers on the integrity of equipment and installation practices, particularly the use of inverters that do not comply with internationally recognized safety and grid synchronization standards such as anti-islanding protection. In a compliant system, the inverter must immediately disconnect when the grid goes down to prevent backfeeding electricity into power lines, which could endanger utility workers performing repairs. Substandard or improperly configured inverters can fail to perform this function, creating a serious safety hazard. Meralco is therefore urging the Department of Energy and the Department of Trade and Industry to formalize equipment certification protocols and require installer accreditation, aligning local practices more closely with standards seen in mature solar markets.
The economic driver behind this shadow market is straightforward. The Philippines has some of the highest retail electricity rates in Southeast Asia, often exceeding ₱10 to ₱12 per kilowatt-hour, equivalent to roughly $0.18 to $0.22. A typical small residential rooftop system installed through formal channels can cost between ₱200,000 and ₱350,000 ($3,600 to $6,300), depending on size and component quality, partly due to compliance costs, engineering studies, and permitting requirements. Guerrilla installers, operating outside this framework, can offer similar grid-tied systems at significantly lower upfront costs by bypassing these steps. For consumers facing persistent energy inflation, the appeal is immediate and tangible, even if it comes with regulatory and technical risks.
The term “guerrilla solar” in the Philippine context does not imply improvised or inherently inferior hardware. Many of these systems use standard photovoltaic panels and commercially available hybrid or grid-tied inverters. The distinction lies in how they are deployed. These installations are connected in parallel to the household electrical system without utility approval and without the installation of a bi-directional meter that can properly record exported energy. In some cases, particularly with older analog meters, excess generation can cause the meter to run backward, effectively reducing recorded consumption. While utilities classify this as a violation of service agreements, many users see it as an informal workaround in a system they perceive as overly restrictive.
From a grid management perspective, the proliferation of unregistered distributed generation introduces uncertainty into load forecasting and voltage regulation. Distribution networks are engineered based on predictable demand patterns and known generation inputs. When hundreds of megawatts of rooftop capacity operate invisibly, it complicates the balancing of supply and demand at the local feeder level. Voltage fluctuations, harmonic distortions, and reverse power flows can occur, particularly in circuits not designed for high levels of distributed energy resources. These conditions can accelerate wear on transformers and other infrastructure, potentially leading to localized outages or equipment damage.
There is also a direct safety dimension. Lineworkers depend on accurate system visibility when de-energizing circuits for maintenance. Undetected backfeeding from rooftop systems can keep lines energized even when they are presumed safe, increasing the risk of electrocution. This is why interconnection standards in the United States and other developed markets mandate certified equipment, inspection, and utility coordination before any grid-tied system is allowed to operate. Meralco’s position reflects a similar engineering logic, emphasizing that the issue is not opposition to solar adoption but the manner in which it is being integrated into the grid.
At the same time, the scale of the guerrilla market signals a structural problem in policy design. Lengthy approval processes, inconsistent local permitting rules, and perceived protection of incumbent utility revenues have created friction that discourages formal participation in net metering. For many Filipino consumers and small businesses, the choice is not between compliant and non-compliant solar, but between slow, expensive compliance and immediate, affordable installation. This dynamic mirrors early-stage distributed solar markets elsewhere, where regulatory lag often trails technological adoption.
The resulting tension is not simply a regulatory dispute but a deeper conflict between centralized grid control and decentralized energy autonomy. Utilities like Meralco are tasked with maintaining reliability and safety across a complex network, while consumers are increasingly empowered by falling solar costs and accessible technology. Whether the government responds with stricter enforcement, streamlined processes, or a combination of both will determine whether these “energy rebels” are absorbed into the formal system or continue operating in parallel.
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